bluuebunny/crossref_metadata_2025 huggingface dataset:
HLA-G expression in melanoma: A way for tumor cells to escape from immunosurveillance
Authors: Paul Pascale , Rouas-Freiss Nathalie , Khalil-Daher Iman , Moreau Philippe , Riteau Beatrice , Le Gal Frederique Anne , Avril Marie Francoise , Dausset Jean , Guillet Jean Gerard , Carosella Edgardo D.
Published: July 2002

Considering the well established role of nonclassical HLA-G class I molecules in inhibiting natural killer (NK) cell function, the consequence of abnormal HLA-G expression in malignant cells should be the escape of tumors from immunosurveillance. To examine this hypothesis, we analyzed HLA-G expression and NK sensitivity in human malignant melanoma cells. Our analysis of three melanoma cell lines andex vivobiopsy demonstrated that (i) IGR and M74 human melanoma cell lines exhibit a high level of HLA-G transcription with differential HLA-G isoform transcription and protein expression patterns, (ii) a higher level of HLA-G transcriptionex vivois detected in a skin melanoma metastasis biopsy compared with a healthy skin fragment from the same individual, and (iii) HLA-G protein isoforms other than membrane-bound HLA-G1 protect IGR from NK lysis. It thus appears of critical importance to consider the specific role of HLA-G expression in tumors in the design of future cancer immunotherapies.
Line spectral analysis for harmonizable processes
Authors: Lii Keh-Shin , Rosenblatt Murray
Published: July 2002

Harmonizable processes with spectral mass concentrated on a number
of straight lines are considered. The asymptotic behavior of the bias
and covariance of a number of spectral estimates is described. The
results generalize those obtained for periodic and almost periodic
processes.
The BRC repeats in BRCA2 are critical for RAD51 binding and resistance to methyl methanesulfonate treatment
Authors: Chen Phang-Lang , Chen Chi-Fen , Chen Yumay , Xiao Jun , Sharp Z. Dave , Lee Wen-Hwa
Published: July 2002

The
BRCA2
gene was identified based on its involvement in familial breast cancer. The analysis of its sequence predicts that the gene encodes a protein with 3,418 amino acids but provides very few clues pointing to its biological function. In an attempt to address this question, specific antibodies were prepared that identified the gene product of
BRCA2
as a 390-kDa nuclear protein. Furthermore, direct binding of human RAD51 to each of the four single 30-amino acid BRC repeats located at the 5′ portion of exon 11 of
BRCA2
was demonstrated. Such an interaction is significant, as BRCA2 and RAD51 can be reciprocally coimmunoprecipitated by each of the individual, specific antibodies and form complexes
in vivo
. Inferring from the function of RAD51 in DNA repair, human pancreatic cancer cells, Capan-1, expressing truncated BRCA2 were shown to be hypersensitive to methyl methanesulfonate (MMS) treatment. Exogenous expression of wild-type BRCA2, but not BRC-deleted mutants, in Capan-1 cells confers resistance to MMS treatment. These results suggest that the interaction between the BRC repeats of BRCA2 and RAD51 is critical for cellular response to DNA damage caused by MMS.
Murine gammaherpesvirus M2 gene is latency-associated and its protein a target for CD8+T lymphocytes
Authors: Husain S. Mazher , Usherwood Edward J. , Dyson Heather , Coleclough Christopher , Coppola Michael A. , Woodland David L. , Blackman Marcia A. , Stewart James P. , Sample Jeffery T.
Published: July 2002

Murine gammaherpesvirus 68 (MHV-68) infection of mice is a potential model with which to address fundamental aspects of the pathobiology and host control of gammaherpesvirus latency. Control of MHV-68 infection, like that of Epstein–Barr virus, is strongly dependent on the cellular immune system. However, the molecular biology of MHV-68 latency is largely undefined. A screen of the MHV-68 genome for potential latency-associated mRNAs revealed that the region encompassing and flanking the genomic terminal repeats is transcriptionally active in the latently infected murine B-cell tumor line S11. Transcription of one MHV-68 gene, that encoding the hypothetical M2 protein, was detected in virtually all latently infected S11 cells and in splenocytes of latently infected mice, but not in lytically infected fibroblasts. Furthermore, an epitope was identified in the predicted M2 protein that is recognized by CD8+T cells from infected mice and a cytotoxic T lymphocyte line that recognizes this epitope killed S11 cells, indicating that the M2 protein is expressed during latent infection and is a target for the host cytotoxic T lymphocyte response. This work therefore provides essential information for modeling MHV-68 latency and strategies of immunotherapy against gammaherpesvirus-related diseases in a highly tractable animal model.
A maternally methylated CpG island in
KvLQT1
is associated with an antisense paternal transcript and loss of imprinting in Beckwith–Wiedemann syndrome
Authors: Smilinich Nancy J. , Day Colleen D. , Fitzpatrick Galina V. , Caldwell Germaine M. , Lossie Amy C. , Cooper P. R. , Smallwood Allan C. , Joyce Johanna A. , Schofield Paul N. , Reik Wolf , Nicholls Robert D. , Weksberg Rosanna , Driscoll D. J. , Maher Eamonn R. , Shows Thomas B. , Higgins Michael J.
Published: July 2002

Loss of imprinting at
IGF2
, generally through an
H19
-independent mechanism, is associated with a large percentage of patients with the overgrowth and cancer predisposition condition Beckwith–Wiedemann syndrome (BWS). Imprinting control elements are proposed to exist within the
KvLQT1
locus, because multiple BWS-associated chromosome rearrangements disrupt this gene. We have identified an evolutionarily conserved, maternally methylated CpG island (
KvDMR1
) in an intron of the
KvLQT1
gene. Among 12 cases of BWS with normal
H19
methylation, 5 showed demethylation of
KvDMR1
in fibroblast or lymphocyte DNA; whereas, in 4 cases of BWS with
H19
hypermethylation, methylation at
KvDMRl
was normal. Thus, inactivation of
H19
and hypomethylation at
KvDMR1
(or an associated phenomenon) represent distinct epigenetic anomalies associated with biallelic expression of
IGF2
. Reverse transcription–PCR analysis of the human and syntenic mouse loci identified the presence of a
KvDMR1
-associated RNA transcribed exclusively from the paternal allele and in the opposite orientation with respect to the maternally expressed
KvLQT1
gene. We propose that
KvDMR1
and/or its associated antisense RNA (
KvLQT1-AS
) represents an additional imprinting control element or center in the human 11p15.5 and mouse distal 7 imprinted domains.
A Holliday junction resolvase from
Pyrococcus furiosus
: Functional similarity to
Escherichia coli
RuvC provides evidence for conserved mechanism of homologous recombination in Bacteria, Eukarya, and Archaea
Authors: Komori Kayoko , Sakae Shinzi , Shinagawa Hideo , Morikawa Kosuke , Ishino Yoshizumi
Published: July 2002

The Holliday junction is an essential intermediate of
homologous recombination. RecA of Bacteria, Rad51 of Eukarya, and RadA
of Archaea are structural and functional homologs. These proteins play
a pivotal role in the formation of Holliday junctions from two
homologous DNA duplexes. RuvC is a specific endonuclease that resolves
Holliday junctions in Bacteria. A Holliday junction-resolving activity
has been found in both yeast and mammalian cells. To examine whether
the paradigm of homologous recombination apply to Archaea, we assayed
and found the activity to resolve a synthetic Holliday junction in
crude extract of
Pyrococcus furiosus
cells. The gene,
hjc
(
H
olliday
j
unction
c
leavage), encodes a protein composed of 123 amino
acids, whose sequence is not similar to that of any proteins with known
function. However, all four archaea, whose total genome sequences have
been published, have the homologous genes. The purified Hjc protein
cleaved the recombination intermediates formed by RecA
in
vitro
. These results support the notion that the formation and
resolution of Holliday junction is the common mechanism of homologous
recombination in the three domains of life.
A transgene insertion creating a heritable chromosome deletion mouse model of Prader-Willi and Angelman syndromes
Authors: Gabriel J. M. , Merchant M. , Ohta T. , Ji Y. , Caldwell R. G. , Ramsey M. J. , Tucker J. D. , Longnecker R. , Nicholls R. D.
Published: July 2002

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) result from the loss of function of imprinted genes in human chromosome 15q11–q13. The central part of mouse chromosome 7 is homologous to human 15q11–q13, with conservation of both gene order and imprinted features. We report here the characterization of a transgene insertion (Epstein–Barr virus Latent Membrane Protein 2A,
LMP2A
) into mouse chromosome 7C, which has resulted in mouse models for PWS and AS dependent on the sex of the transmitting parent. Epigenotype (allelic expression and DNA methylation) and fluorescence
in situ
hybridization analyses indicate that the transgene-induced mutation has generated a complete deletion of the PWS/AS-homologous region but has not deleted flanking loci. Because the intact chromosome 7, opposite the deleted homolog, maintains the correct imprint in somatic cells of PWS and AS mice and establishes the correct imprint in male and female germ cells of AS mice, homologous association and replication asynchrony are not part of the imprinting mechanism. This heritable-deletion mouse model will be particularly useful for the identification of the etiological genes and mechanisms, phenotypic basis, and investigation of therapeutic approaches for PWS.
Characterization of a manganese-dependent regulatory protein, TroR, from
Treponema pallidum
Authors: Posey James E. , Hardham John M. , Norris Steven J. , Gherardini Frank C.
Published: July 2002

Genome sequence analysis of
Treponema pallidum
,
the causative agent of syphilis, suggests that this bacterium has a limited iron requirement with few, if any, proteins that require iron. Instead,
T. pallidum
may use manganese-dependent enzymes for metabolic pathways. This strategy apparently alleviates the necessity of
T. pallidum
to acquire iron from the host, thus overcoming iron limitation, which is a primary host defense. Interestingly, a putative metal-dependent regulatory protein, TroR, which has homology with the diphtheria toxin regulatory protein, DtxR, from
Corynebacterium diphtheriae
was identified from
T. pallidum
. We describe here the characterization of TroR, a regulatory protein. Mobility-shift DNA binding and DNase I footprint assays indicated that purified TroR bound to a 22-nt region of dyad symmetry that overlaps the −10 region of the promoter of the
tro
operon, which contains the genes for a putative metal transport system, the glycolytic enzyme phosphoglycerate mutase, and TroR. Unlike other metal-dependent regulatory proteins like diphtheria toxin regulatory protein and the ferric ion uptake regulator, Fur, which can be activated by divalent metals such as Fe
2+
, Mn
2+
, Co
2+
, Ni
2+
, and Zn
2+
, TroR is activated only by Mn
2+
. The TroR-Mn
2+
complex binds its target sequence and blocks transcription of the
tro
PO/
lacZ
fusion, suggesting that TroR acts as a metal-dependent repressor
in vivo
. In addition, TroR exists as a dimer in both its inactive (metal free) and active states as indicated by chemical crosslinking experiments. Based on these data, we propose that TroR represents a unique regulatory system for controlling gene expression in
T. pallidum
in response to Mn
2+
.
Nitric oxide synthase in cardiac sarcoplasmic reticulum
Authors: Xu Kai Y. , Huso David L. , Dawson Ted M. , Bredt David S. , Becker Lewis C.
Published: July 2002

NO
⋅
is a free radical that modulates heart function and metabolism. We report that a neuronal-type NO synthase (NOS) is located on cardiac sarcoplasmic reticulum (SR) membrane vesicles and that endogenous NO
⋅
produced by SR-associated NOS inhibits SR Ca
2+
uptake. Ca
2+
-dependent biochemical conversion of
l
-arginine to
l
-citrulline was observed from isolated rabbit cardiac SR vesicles in the presence of NOS substrates and cofactors. Endogenous NO
⋅
was generated from the vesicles and detected by electron paramagnetic resonance spin-trapping measurements. Immunoelectron microscopy demonstrated labeling of cardiac SR vesicles by using anti-neuronal NOS (nNOS), but not anti-endothelial NOS (eNOS) or anti-inducible NOS (iNOS) antibodies, whereas skeletal muscle SR vesicles had no nNOS immunoreactivity. The nNOS immunoreactivity also displayed a pattern consistent with SR localization in confocal micrographs of sections of human myocardium. Western blotting demonstrated that cardiac SR NOS is larger than brain NOS (160 vs. 155 kDa). No immunodetection was observed in cardiac SR vesicles from nNOS knockout mice or with an anti-nNOSμ antibody, suggesting the possibility of a new nNOS-type isoform.
45
Ca uptake by cardiac SR vesicles, catalyzed by Ca
2+
-ATPase, was inhibited by NO
⋅
produced endogenously from cardiac SR NOS, and 7-nitroindazole, a selective nNOS inhibitor, completely prevented this inhibition. These results suggest that a cardiac muscle nNOS isoform is located on SR of cardiac myocytes, where it may respond to intracellular Ca
2+
concentration and modulate SR Ca
2+
ion active transport in the heart.
A cytochromeb5is required for full activity of flavonoid 3′,5′-hydroxylase, a cytochrome P450 involved in the formation of blue flower colors
Authors: de Vetten Nick , ter Horst Jeroen , van Schaik Henk-Peter , de Boer Albertus , Mol Joseph , Koes Ronald
Published: July 2002

The substitution pattern of anthocyanin pigments is a main determinant of flower color. Flavonoid 3′,5′-hydroxylase (F3′5′H) is a cytochrome P450 enzyme (Cyt P450) that catalyzes the 3′,5′-hydroxylation of dihydroflavonols, the precursors of purple anthocyanins. Species such as rose and carnation lack F3′5′H activity and are, therefore, unable to generate purple or blue flowers. Petunia, on the other hand, contains two loci, termedhf1andhf2, that encode a Cyt P450 with F3′5′H activity. Here we report the identification of an additional petunia gene that is required for 3′,5′ substitution of anthocyanins and purple flower colors. It encodes a cytochromeb5and is expressed exclusively in the flower. Inactivation of the gene by targeted transposon mutagenesis reduced F3′5′H enzyme activity and the accumulation of 5′-substituted anthocyanins, resulting in an altered flower color. However, no phenotypic effect on the activity of other Cyt P450s, involved in the synthesis of hormones or general phenylpropanoids, was observed. These data providein vivoevidence for the regulation of the activity of specific Cyt P450s by a cytochromeb5.
Conformational flexibility at the substrate binding site in the lactose permease of
Escherichia coli
Authors: Weinglass Adam B. , Kaback H. Ronald
Published: July 2002

Glu-126 (helix IV) and Arg-144 (helix V) are charge paired and play a critical role in substrate binding in the lactose permease of
Escherichia coli
. When Glu-126 is replaced with Asp, the permease has relatively high activity, implying that helix V has sufficient flexibility to allow Arg-144 to accommodate the decreased length of the carboxylate-containing side chain of Asp-126. Helices IV and V contain five Gly residues at positions 115, 121, 141, 147, and 150, all of which are conserved in the oligosaccharide/H
+
symport family of the major facilitator superfamily. To test the notion that these residues may contribute to conformational flexibility, each residue was replaced with Ala in either the wild type or the Glu-126 → Asp mutant. Although the replacements are well tolerated in the wild type, the mutations severely inactivate substrate binding and transport in the Glu-126 → Asp background, with the exception of Gly-121 → Ala, which retains significant activity. Strikingly, moreover, in two instances (Gly-150 → Ala and Gly-141 → Ala), significant activity is recovered when Ala residues at approximately parallel positions in helix IV (Ala-122 or Ala-127, respectively) are replaced with Gly. In addition to providing further evidence that the major determinants for substrate binding in the permease are at the interface between helices IV and V, the findings indicate that the region is conformationally flexible.
Replacement of the proximal heme thiolate ligand in chloroperoxidase with a histidine residue
Authors: Yi Xianwen , Mroczko Mark , Manoj Kelath M. , Wang Xiaotang , Hager Lowell P.
Published: July 2002

Chloroperoxidase is a versatile heme enzyme which can cross over the catalytic boundaries of other oxidative hemoproteins and perform multiple functions. Chloroperoxidase, in addition to catalyzing classical peroxidative reactions, also acts as a P450 cytochrome and a potent catalase. The multiple functions of chloroperoxidase must be derived from its unique active site structure. Chloroperoxidase possesses a proximal cysteine thiolate heme iron ligand analogous to the P450 cytochromes; however, unlike the P450 enzymes, chloroperoxidase possesses a very polar environment distal to its heme prosthetic group and contains a glutamic acid residue in close proximity to the heme iron. The presence of a thiolate ligand in chloroperoxidase has long been thought to play an essential role in its chlorination and epoxidation activities; however, the research reported in this paper proves that hypothesis to be invalid. To explore the role of Cys-29, the amino acid residue supplying the thiolate ligand in chloroperoxidase, Cys-29 has been replaced with a histidine residue. Mutant clones of the chloroperoxidase genome have been expressed in aCaldariomyces fumagoexpression system by using gene replacement rather than gene insertion technology.C. fumagoproduces wild-type chloroperoxidase, thus requiring gene replacement of the wild type by the mutant gene. To the best of our knowledge, this is the first time that gene replacement has been reported for this type of fungus. The recombinant histidine mutants retain most of their chlorination, peroxidation, epoxidation, and catalase activities. These results downplay the importance of a thiolate ligand in chloroperoxidase and suggest that the distal environment of the heme active site plays the major role in maintaining the diverse activities of this enzyme.
Clinical relevance of the
Helicobacter pylori
gene for blood-group antigen-binding adhesin
Authors: Gerhard Markus , Lehn Norbert , Neumayer Nina , Borén Thomas , Rad Roland , Schepp Wolfgang , Miehlke Stephan , Classen Meinhard , Prinz Christian
Published: July 2002

Infection with
Helicobacter pylori
is associated with different human gastric diseases. Biochemical studies,
in vitro
adherence assays, and
in vivo
animal models revealed that epithelial attachment of
H. pylori
can be mediated by the blood-group antigen-binding adhesin (BabA) targeting human Lewis
b
surface epitopes. Studies with transgenic mice expressing the Lewis
b
epitope have shown that such attachment can alter disease outcome. In the current study, the presence of the
babA2
gene encoding the adhesin was investigated in clinical isolates from a German population by using PCR and reverse transcription–PCR. A positive genotype was correlated to allelic variations in the genes encoding VacA and CagA and also to the prevalence of duodenal ulcer, distal gastric adenocarcinoma, mucosa-associated lymphoid tissue lymphoma, and antral gastritis. The presence of
babA2
was significantly associated with duodenal ulcer (
P
= 0.0002) and adenocarcinoma (
P
= 0.033). In contrast, type 1 strains (
vacAs1-
and
cagA
-positive) were associated with only duodenal ulcer (
P
= 0.004) but not adenocarcinoma (
P
= 0.235). Genotype presence of
babA2
,
vacAs1
, and
cagA
(“triple-positive” strains) showed a highly significant correlation to the prevalence of ulcer (
P
= 0.000002) and adenocarcinoma (
P
= 0.014) and discriminated significantly better between disease outcome than did the current type 1 classification. These results indicate that the
babA2
gene is of high clinical relevance and would be a useful marker to identify patients who are at higher risk for specific
H. pylori-
related diseases.
Image recognition: Visual grouping, recognition, and learning
Authors: Buhmann Joachim M. , Malik Jitendra , Perona Pietro
Published: July 2002

Vision extracts useful information from images. Reconstructing the three-dimensional structure of our environment and recognizing the objects that populate it are among the most important functions of our visual system. Computer vision researchers study the computational principles of vision and aim at designing algorithms that reproduce these functions. Vision is difficult: the same scene may give rise to very different images depending on illumination and viewpoint. Typically, an astronomical number of hypotheses exist that in principle have to be analyzed to infer a correct scene description. Moreover, image information might be extracted at different levels of spatial and logical resolution dependent on the image processing task. Knowledge of the world allows the visual system to limit the amount of ambiguity and to greatly simplify visual computations. We discuss how simple properties of the world are captured by the Gestalt rules of grouping, how the visual system may learn and organize models of objects for recognition, and how one may control the complexity of the description that the visual system computes.
Specific mutations in a viral RNA pseudoknot drastically change ribosomal frameshifting efficiency
Authors: Kim Yang-Gyun , Su Li , Maas Stefan , O’Neill Analeah , Rich Alexander
Published: July 2002

Many viruses regulate protein synthesis by −1 ribosomal frameshifting using an RNA pseudoknot. Frameshifting is vital for viral reproduction. Using the information gained from the recent high-resolution crystal structure of the beet western yellow virus pseudoknot, a systematic mutational analysis has been carried out
in vitro
and
in vivo
. We find that specific nucleotide tertiary interactions at the junction between the two stems of the pseudoknot are crucial. A triplex is found between stem 1 and loop 2, and triplex interactions are required for frameshifting function. For some mutations, loss of one hydrogen bond is sufficient to abolish frameshifting. Furthermore, mutations near the 5′ end of the pseudoknot can increase frameshifting by nearly 300%, possibly by modifying ribosomal contacts. It is likely that the selection of suitable mutations can thus allow viruses to adjust frameshifting efficiencies and thereby regulate protein synthesis in response to environmental change.
Insulin-like growth factor binding protein 2 is a growth inhibitory protein conserved in zebrafish
Authors: Duan Cunming , Ding Jun , Li Qin , Tsai Wellington , Pozios Kasiani
Published: July 2002

Fish serum contains several specific binding proteins for insulin-like growth factors (IGFBPs). The structure and physiological function of these fish IGFBPs are unknown. Here we report the complete primary sequence of a zebrafish IGFBP deduced from cDNA clones isolated by library screening and rapid amplification of cDNA ends. The full-length 1,757-bp cDNA encodes a protein of 276 aa, which contains a putative 22-residue signal peptide and a 254-residue mature protein. The mature zebrafish IGFBP has a predicted molecular size of 28,440 Da and shows high sequence identity with human IGFBP-2 (52%). The sequence identities with other human IGFBPs are <37%. Chinese hamster ovary cells stably transfected with the zebrafish IGFBP-2 cDNA secreted a 31-kDa protein, which bound to IGF-I and IGF-II with high affinity, but did not bind to Des(1–3)IGF-I or insulin. Northern blot analyses revealed that the zebrafish IGFBP-2 transcript is a 1.8-kb band expressed in many embryonic and adult tissues. In adult zebrafish, IGFBP-2 mRNA levels were greatly reduced by growth hormone treatment but increased by prolonged fasting. When overexpressed or added to cultured zebrafish and mammalian cells, the zebrafish IGFBP-2 significantly inhibited IGF-I-stimulated cell proliferation and DNA synthesis. These results indicate that zebrafish IGFBP-2 is a negative growth regulator acting downstream in the growth hormone-IGF-I axis.
A risk assessment for exposure to grunerite asbestos (amosite) in an iron ore mine
Authors: Nolan R. P. , Langer A. M. , Wilson Richard
Published: July 2002

The potential for health risks to humans exposed to the asbestos
minerals continues to be a public health concern. Although the
production and use of the commercial amphibole asbestos
minerals—grunerite (amosite) and riebeckite (crocidolite)—have been
almost completely eliminated from world commerce, special opportunities
for potentially significant exposures remain. Commercially viable
deposits of grunerite asbestos are very rare, but it can occur as a
gangue mineral in a limited part of a mine otherwise thought
asbestos-free. This report describes such a situation, in which a very
localized seam of grunerite asbestos was identified in an iron ore
mine. The geological occurrence of the seam in the ore body is
described, as well as the mineralogical character of the grunerite
asbestos. The most relevant epidemiological studies of workers exposed
to grunerite asbestos are used to gauge the hazards associated with the
inhalation of this fibrous mineral. Both analytical transmission
electron microscopy and phase-contrast optical microscopy were used to
quantify the fibers present in the air during mining in the area with
outcroppings of grunerite asbestos. Analytical transmission electron
microscopy and continuous-scan x-ray diffraction were used to determine
the type of asbestos fiber present. Knowing the level of the miner’s
exposures, we carried out a risk assessment by using a model developed
for the Environmental Protection Agency.
A cytosine analog that confers enhanced potency to antisense oligonucleotides
Authors: Flanagan W. Michael , Wolf John J. , Olson Peter , Grant Debbie , Lin Kuei-Ying , Wagner Richard W. , Matteucci Mark D.
Published: July 2002

Antisense technology is based on the ability to design potent, sequence-specific inhibitors. The G-clamp heterocycle modification, a cytosine analog that clamps on to guanine by forming an additional hydrogen bond, was rationally designed to enhance oligonucleotide/RNA hybrid affinity. A single, context-dependent substitution of a G-clamp heterocycle into a 15-mer phosphorothioate oligodeoxynucleotide (S-ON) targeting the cyclin-dependent kinase inhibitor, p27
kip1
, enhanced antisense activity as compared with a previously optimized C5-propynyl-modified p27
kip1
S-ON and functionally replaced 11 C5-propynyl modifications. Dose-dependent, sequence-specific antisense inhibition was observed at nanomolar concentrations of the G-clamp S-ONs. A single nucleotide mismatch between the G-clamp S-ON and the p27
kip1
mRNA reduced the potency of the antisense ON by five-fold. A 2-base-mismatch S-ON eliminated antisense activity, confirming the sequence specificity of G-clamp-modified S-ONs. The G-clamp-substituted p27
kip1
S-ON activated RNase H-mediated cleavage and demonstrated increased
in vitro
binding affinity for its RNA target compared with conventional 15-mer S-ONs. Furthermore, incorporation of a single G-clamp modification into a previously optimized 20-mer phosphorothioate antisense S-ON targeting c-raf increased the potency of the S-ON 25-fold. The G-clamp heterocycle is a potent, mismatch-sensitive, automated synthesizer-compatible antisense S-ON modification that will have important applications in the elucidation of gene function, the validation of gene targets, and the development of more potent antisense-based pharmaceuticals.
Improved reporter strain for monitoring Cre recombinase-mediated DNA excisions in mice
Authors: Mao Xiaohong , Fujiwara Yuko , Orkin Stuart H.
Published: July 2002

Effective use of conditional Cre recombinase-
loxP
gene modification requires Cre-expressing mouse strains with defined patterns of expression. To assess the
in vivo
functionality of Cre-expressing mice, we have engineered an improved reporter strain for monitoring Cre-mediated excisions. The β-galactosidase-neomycin phosphotransferase fusion gene (βgeo)-trapped ROSA26 locus was modified by gene targeting such that βgeo is expressed only after Cre-mediated excision of
loxP
-flanked DNA sequences. βgeo from the excised ROSA26 allele is expressed ubiquitously in embryos and adult mice. By mating the reporter strain with Cre-expressing transgenic mice, we have shown that the
loxP
-flanked ROSA26 allele is accessible to Cre during early embryogenesis, as well as in a specific hematopoietic lineage (T lymphocytes). This improved reporter strain should facilitate monitoring
in vivo
Cre-mediated excision events in a variety of experimental contexts.
Elongin BC complex prevents degradation of von Hippel-Lindau tumor suppressor gene products
Authors: Schoenfeld Alan R. , Davidowitz Eliot J. , Burk Robert D.
Published: July 2002

Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene causes the familial cancer syndrome, VHL disease, characterized by a predisposition to renal cell carcinoma and other tumor types. Loss of VHL gene function also is found in a majority of sporadic renal carcinomas. A preponderance of the tumor-disposing inherited missense mutations detected in VHL disease are within the elongin-binding domain of VHL. This region mediates the formation of a multiprotein VHL complex containing elongin B, elongin C, cul-2, and Rbx1. This VHL complex is thought to function as an E3 ubiquitin ligase. Here, we report that VHL proteins harboring mutations which disrupt elongin binding are unstable and rapidly degraded by the proteasome. In contrast, wild-type VHL proteins are directly stabilized by associating with both elongins B and C. In addition, elongins B and C are stabilized through their interactions with each other and VHL. Thus, the entire VHL/elongin complex is resistant to proteasomal degradation. Because the elongin-binding domain of VHL is frequently mutated in cancers, these results suggest that loss of elongin binding causes tumorigenesis by compromising VHL protein stability and/or potential VHL ubiquitination functions.
Transposable elements in sexual and ancient asexual taxa
Authors: Arkhipova Irina , Meselson Matthew
Published: July 2002

Sexual reproduction allows deleterious transposable elements to
proliferate in populations, whereas the loss of sex, by preventing
their spread, has been predicted eventually to result in a population
free of such elements [Hickey, D. A. (1982)
Genetics
101, 519–531]. We tested this
expectation by screening representatives of a majority of animal phyla
for LINE-like and gypsy-like reverse transcriptases and
mariner/Tc1-like transposases. All species tested positive for
reverse transcriptases except rotifers of the class Bdelloidea, the
largest eukaryotic taxon in which males, hermaphrodites, and meiosis
are unknown and for which ancient asexuality is supported by molecular
genetic evidence. Mariner-like transposases are distributed
sporadically among species and are present in bdelloid rotifers. The
remarkable lack of LINE-like and gypsy-like retrotransposons in
bdelloids and their ubiquitous presence in other taxa support the view
that eukaryotic retrotransposons are sexually transmitted nuclear
parasites and that bdelloid rotifers evolved asexually.
The Psychosocial Development of Children and Adolescents in the People's Republic of China: An Eriksonian Approach
Authors: Wang Wei , Viney Linda L.
Published: July 2002

This exploratory study of Eriksonian psychosocial development in school‐aged children in the People's Republic of China tested the feasibility of Erikson's model with 360 students from 6 primary and high schools. The 16 Content Analysis Scales of Psychosocial Maturity were applied to the transcribed verbalizations from an open‐ended interview and the scale scores were analyzed with two factors, school grade and gender. The grade‐related results indicated that the development of psychosocial maturity among these school students showed some consistency with Erikson's model in terms of stage‐relevant experience. However, resolution of industry versus inferiority was the main focus of all the research participants. Identity versus identity diffusion was emerging among high school students. A high level of trust existed for all school grades, but grade 1 consistently scored higher than other grades for all aspects of psychosocial maturity. No significant gender difference was found for any stage experience. The implications for the findings and the limitations of the methodology have been discussed.
Determinants of Readiness for Out‐group Social Contact: Dominance Relations and Minority Group Motivations
Authors: Sagiv Lilach , Schwartz Shalom H.
Published: July 2002

Findings that members of minorities are more ready for social contact with members of dominant groups than vice versa have been attributed to a motivation of minorities to integrate into the larger society. We theorize that minorities hold opposing motivations—to integrate vs. to maintain unique group identity—the balance of which determines readiness for out‐group contact. Study 1 examined readiness for out‐group contact among three groups of Israeli teachers—Jews (dominant group), Muslim Arabs, and Christian Arabs (minorities). According to sociohistorical analyses, Muslim Arabs are more activated to maintain uniqueness and less motivated to integrate than are Christian Arabs. Study 2 examined recent Russian immigrants to Israel (minority) and veteran Israelis (dominant). Individual differences in motivation to integrate vs. maintain minority group identity were measured among immigrants. In both studies, the balance of motivations predicted minority group readiness for contact with the dominant group.
Urban Economic Growth in Europe: Testing Theory and Policy Prescriptions
Authors: Cheshire Paul , Carbonaro G.
Published: July 2002

A quite robust model of differential growth rates of per capita income in the major functional urban regions of the European Union is presented and tested for the 1980s. The results underline the important role of purely spatial economic processes in differential regional growth and suggest that the pattern of European urbanisation tends itself to generate systematic divergence of mean per capita incomes between neighbouring city-regions, even though the mechanism generating this divergence of mean incomes is not inconsistent with converging incomes for comparable individuals. In addition, the evidence is supportive of a spatial adaptation of Romer's endogenous technical progress model. The model is formulated in a way which tests policy concerns. In general, the results are supportive of European regional policy although the systematic spatial effects of European integration seem to be fading and extending outwards to near-peripheral urban regions.
Social Polarisation, Economic Restructuring and Welfare State Regimes
Authors: Hamnett Chris
Published: July 2002

The central argument of this paper is that it is misconceived to view social polarisation of occupational structure and incomes in global cities as either inevitable or as a direct product of economic restructuring. It is argued that this neglects the key role of different welfare state structures which can and do influence both occupational and income structures independently of the processes of economic restructuring. The form and extent of polarisation in different cities are likely to reflect the nature and form of welfare state regimes in different countries as well as the form of economic restructuring and other factors such as the scale of immigration. Evidence from London suggests that growing income polarisation is accompanied by a professionalisation of the occupational structure.
The Muslim Experience in the Balkan States, 1919–19911
Authors: Poulton Hugh
Published: July 2002

During the nineteenth century, the Ottoman Empire retreated from the Balkans, and underwent a steady decline culminating in its final demise in the early part of the twentieth century. Sizeable communities of Muslims, derived both from those who had arrived with the Ottomans and from indigenous inhabitants who had converted to Islam, remained in the new successor states of southeast Europe. With the exception of Albania, where the Muslims formed the majority of the population, these communities became established as minorities within the new states. Upheld as ethno-national states each based on one dominant nation, the new states suffered from irredentism on the one hand, and internal tension between majority and minority populations on the other. Tension was particularly evident in the relations between the new Orthodox Christian rulers and their Muslim minority populations, which were seen as undesirable relics from the Ottoman past. In spite of such attitudes and the continuing waves of emigration, however, these Muslim communities remain an integral part of the present-day Balkans.
Children and School‐based Research: ‘informed consent’ or ‘educated consent’?
Authors: David Miriam , Edwards Rosalind , Alldred Pam
Published: July 2002

Abstract This article discusses ‘informed consent’ in relation to research with children and young people in educational settings. In particular, it reflects upon issues that arose in the process of gaining their active consent to participate in the authors’ research on children's understandings of parental involvement in education. In line with contemporary approaches to research with children, the children were provided with ‘information’ through leaflets and classroom activities in order for them to make ‘choices’ about participation. On reflection, these methods can be seen as distinctly educational, in that they drew on liberal education discourses and on practices adopted in ‘progressive’ British schooling. The children and young people's responses to the consent processes must be seen in the context of the authors’ implicit use of broadly pedagogic approaches, and of the research taking place in a school setting inscribed with differential power relations. The authors therefore interrogate the concept of ‘informed consent’ that is employed in research, and its prior construction of ‘information’. This raises questions about distinctions between providing information and teaching, and implications for conducting ethical social research with children.
The early experience assumption: Past, present, and future
Authors: Schaffer H. Rudolph
Published: July 2002

The assumption that “early experience is important” has attracted a considerable amount of research over the last half century. As a result, both our thinking about the role of early experience in personality development and the nature of that research have changed drastically. It has become apparent that there is no direct relationship between age and the impact which experience has on the individual, that young children are not necessarily more vulnerable even to quite severe adversities than older children, and that considerable variability exists in long-term outcome. Research has therefore had to take an evermore complex form, moving away from a mechanical association of early experience with outcome assessments to a much more dynamically oriented approach, in which account is also taken of inherent characteristics of the individual, the social context both before and after the experience, and the various turning points that the individual negotiates in traversing the developmental path to maturity. Prospective longitudinal studies are therefore essential to our understanding of the link between early experience and later adjustment, and these studies need to include not only accounts of the external experiences encountered but also assessments of the individual’s internal representations resulting from the encounters. It has also become apparent that some behaviour systems are more vulnerable than others and that a more thoughtful use of outcome measures is therefore necessary. Although the belief in the irreversibility of early experience as inevitable has been abandoned, the parameters defining the limits of reversibility have yet to be determined.
Individual differences and consistency in maternal talk style during joint story encoding and retrospection: Associations with children’s long-term recall
Authors: Low Jason , Durkin Kevin
Published: July 2002

The manner in which parents and children reminisce about personal events has received increasing attention over the last decade as it has important implications for children’s memory performance. How individual differences in maternal talk style relate to children’s story recall is less clear. The present study examined stylistic consistencies and changes between initial mother-child online encoding of a story event (T1) and between mother-child retrospections about the same story event 4 months later (T2), 8 months later (T3), and 12 months later (T4). Twenty-four children, 72-months-old at T1, and their mothers participated. During story encoding, mothers could be classi” ed as high or low elaborative. Relative differences between these maternal groups endured over time. Children of high elaborative mothers contributed more story information than children of low elaborative mothers at each of the four time points. Constraints and implications of the study are discussed.
Teenage job aspirations and career attainment in adulthood: A 17-year follow-up study of teenagers who aspired to become scientists, health professionals, or engineers
Authors: Schoon Ingrid
Published: July 2002

A longitudinal perspective was taken to investigate the predictive validity of teenage job aspirations, and the relative impact of individual and contextual factors on the formulation and realisation of career aspirations at age 16. The follow-up study of a nationally representative cohort of 7649 individuals born in the United Kingdom showed that teenage job aspirations predict specific occupational attainments in adulthood. Job aspirations expressed in adolescence differed between the sexes, and were related to parental education, teacher-ratings and self-ratings of ability, test scores in mathematics, and the school environment. Occupational attainment at age 33 was significantly related to the job aspirations expressed at age 16, but also to the belief in one’s own ability, mathematical test performance, specific personality characteristics, as well as social background and gender. It is concluded that for the understanding of occupational development across the lifespan both individual and contextual factors have to be considered.
The organisation of Luo conceptions of intelligence: A study of implicit theories in a Kenyan village
Authors: Grigorenko Elena L. , Geissler P. Wenzel , Prince Ruth , Okatcha Frederick , Nokes Catherine , Kenny David A. , Bundy Donald A. , Sternberg Robert J.
Published: July 2002

This article examines the organisation of concepts of intelligence among the Luo people in rural Kenya. In particular, it discusses what the components of these concepts are; how these components are expressed in the DhoLuo language, how they are interrelated, how they are used in judgements of other people, and how these components of Luo conceptions of intelligence are related to Western conceptions of intelligence. Peer, teacher, and adult in the community ratings of children on Luo components of intelligence are correlated with performance on conventional ability tests and with school achievement. The Luo concept of intelligence is primarily expressed in the DhoLuo vocabulary by four concepts (rieko, luoro, paro, and winjo), which appear to form two latent structures, social-emotional competence and cognitive competence. Indicators of only one of these concepts (rieko) and only one latent structure (cognitive competence) correlate with scores on conventional Western cognitive ability tests and with school achievement in English and mathematics. The article also presents a novel method for analysing data from people’s ratings of each other’s intelligence that is useful when not every one who is providing the ratings knows everyone who is to be rated, and when Likert rating scales are inapplicable.
Cultural variations in the play of toddlers
Authors: Göncü Artin , Mistry Jayanthi , Mosier Christine
Published: July 2002

The present study examines differences in the social play of toddlers from four communities. Fourteen children, between the ages of 12 and 24 months, from four cultural communities (San Pedro, Guatemala; Kecioren, Turkey; Dhol-Ki-Patti, India; Salt Lake City, United States) participated in the study. This paper is based on an analysis of data from a larger study, which was designed to examine guided participation between caregivers and toddlers during daily routine activities (Rogoff, Mistry, Göncü, & Mosier, 1993). This study specifically examines episodes of social play which occurred during various activities. We addressed community differences in the occurrence, frequency, partners, and dynamics of social play. We also examined whether or not the kinds (i.e. pretend, object, physical, language, and games) and themes of children’s play varied as a function of the activity (i.e. exploring novel objects, dressing, free activity, and adult conversation) in which the play activities were embedded. The results indicated that social play occurred in each of the four communities, although the frequency and partners of social play presented cultural variations. Also, there were cultural variations in the numbers of children who engaged in the various kinds of play examined. Based on our results we conclude that developmental play theory should be extended to take into account cultural variation.
Adolescent-parent discrepancies in perceptions of family functioning and early adolescent self-competence
Authors: Ohannessian Christine McCauley , Lerner Jacqueline V. , Lerner Richard M. , von Eye Alexander
Published: July 2002

The relationship between discrepancies in adolescents’ and their parents’ perceptions of family functioning and adolescent self-competence was examined in a sample of 74 sixth and seventh grade students and their parents. This relationship was examined by the gender of the adolescent and the gender of the parent. Results indicated that discrepancies in adolescent-mother and adolescent-father perceptions of family functioning were related to lower levels of adolescent self-competence for girls. For boys, discrepancies in adolescent-mother perceptions of family functioning were also related to lower levels of adolescent self-competence, however, discrepancies in adolescent-father perceptions of family functioning were related to higher levels of adolescent self-competence. Explanations for these gender differences are provided. For both girls and boys, discrepancies in perceptions of family functioning predicted lower levels of self-competence and lower levels of self-competence predicted discrepancies in perceptions of family functioning. Consistent with current models of human development, these results emphasise the importance of examining both directions of influence when relationships between characteristics of the individual and the family context are explored.
A Social-contextual Model of Coping with Everyday Problems across the Lifespan
Authors: Berg Cynthia A. , Meegan Sean P. , Deviney Frances P.
Published: July 2002

The paper describes a social-contextual model of the process whereby individuals in connection with others anticipate and cope with everyday life problems. From this model, appraisal and stress are conceptualised at a variety of levels, ranging from solely individual appraisal of everyday problems to integrated and shared relational appraisal by a social unit. Coping efforts likewise range from solely individual efforts to highly collaborative efforts. Our developmental work on everyday problem solving is used to illustrate how coping efforts are embedded in a rich social context, are appraised within that context, and frequently involve the use of others in ways that extend beyond using individuals for support. Our work suggests a reorientation of stress and coping research away from documenting general developmental differences in coping strategies to understanding the process whereby individuals and others in their social context anticipate and cope with everyday life problems. We suggest that this process is a dynamic one in which microdevelopmental change across a current coping situation and macrodevelopmental change across the lifespan are examined.