bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of cyclin-dependent kinase 5 catalytic activity by phosphorylation
Authors: Sharma Pushkar , Sharma Monica , Amin Niranjana D. , Albers R. Wayne , Pant Harish C.
Published: July 2002

Cyclin-dependent kinase 5 (cdk5) is found in an active form only in neuronal cells. Activation by virtue of association with the cyclin-like neuronal proteins p35 (or its truncated form p25) and p39 is the only mechanism currently shown to regulate cdk5 catalytic activity. In addition to cyclin binding, other members of the cdk family require for maximal activation phosphorylation of a Ser/Thr residue (Thr
160
in the case of cdk-2) that is conserved in all cdks except cdk8. This site is phosphorylated by cdk-activating kinases, which, however, do not phosphorylate cdk5. To examine the possible existence of a phosphorylation-dependent regulatory mechanism in the case of cdk5, we have metabolically labeled PC12 cells with
32
P
i
and shown that the endogenous cdk5 is phosphorylated. Bacterially expressed cdk5 also can be phosphorylated by PC12 cell lysates. Phosphorylation of cdk5 by a PC12 cell lysate results in a significant increase in cdk5/p25 catalytic activity. Ser
159
in cdk5 is homologous to the regulatory Thr
160
in cdk2. A Ser
159
-to-Ala (S159A) cdk5 mutant did not show similar activation, which suggests that cdk5 is also regulated by phosphorylation at this site. Like other members of the cdk family, cdk5 catalytic activity is influenced by both p25 binding and phosphorylation. We show that the cdk5-activating kinase (cdk5AK) is distinct from the cdk-activating kinase (cyclin H/cdk7) that was reported previously to neither phosphorylate cdk5 nor affect its activity. We also show that casein kinase I, but not casein kinase II, can phosphorylate and activate cdk5
in vitro
.
RING fingers mediate ubiquitin-conjugating enzyme (E2)-dependent ubiquitination
Authors: Lorick Kevin L. , Jensen Jane P. , Fang Shengyun , Ong Albert M. , Hatakeyama Shigetsugu , Weissman Allan M.
Published: July 2002

A RING finger-containing protein (AO7) that binds ubiquitin-conjugating enzymes (E2s) and is a substrate for E2-dependent ubiquitination was identified. Mutations of cation-coordinating residues within AO7’s RING finger abolished ubiquitination, as did chelation of zinc. Several otherwise-unrelated RING finger proteins, including BRCA1, Siah-1, TRC8, NF-X1, kf-1, and Praja1, were assessed for their ability to facilitate E2-dependent ubiquitination. In all cases, ubiquitination was observed. The RING fingers were implicated directly in this activity through mutations of metal-coordinating residues or chelation of zinc. These findings suggest that a large number of RING finger-containing proteins, with otherwise diverse structures and functions, may play previously unappreciated roles in modulating protein levels via ubiquitination.
A putative mechanism of demyelination in multiple sclerosis by a proteolytic enzyme, calpain
Authors: Shields Donald C. , Schaecher Kurt E. , Saido Takaomi C. , Banik Naren L.
Published: July 2002

In autoimmune demyelinating diseases such as multiple sclerosis (MS), the degradation of myelin proteins results in destabilization of the myelin sheath. Thus, proteases have been implicated in myelin protein degradation, and recent studies have demonstrated increased expression and activity of a calcium-activated neutral proteinase (calpain) in experimental allergic encephalomyelitis, the corresponding animal model of MS. In the present study, calpain activity and expression (at translational and transcriptional levels) were evaluated in white matter from human patients with MS and Parkinson’s and Alzheimer’s diseases and compared with that of white matter from normal controls. Western blot analysis revealed that levels of the active form of calpain and calpain-specific degradation products (fodrin) were increased by 90.1% and 52.7%, respectively, in MS plaques compared with normal white matter. Calpain translational expression was up-regulated by 462.5% in MS plaques compared with controls, although levels of the specific endogenous inhibitor, calpastatin, were not altered significantly. At the transcriptional level, no significant changes in calpain or calpastatin expression were detected by reverse transcription–PCR. Using double immunofluorescent labeling, increased calpain expression was observed in reactive astrocytes, activated T cells, and activated mononuclear phagocytes in and adjacent to demyelinating lesions. Calpain activity and translational expression were not increased significantly in white matter from patients with Parkinson’s or Alzheimer’s diseases compared with that of normal controls. Because calpain degrades all major myelin proteins, the increased activity and expression of this proteinase may play a critical role in myelinolysis in autoimmune demyelinating diseases such as MS.
Insulin selectively increases SREBP-1c mRNA in the livers of rats with streptozotocin-induced diabetes
Authors: Shimomura Iichiro , Bashmakov Yuriy , Ikemoto Shinji , Horton Jay D. , Brown Michael S. , Goldstein Joseph L.
Published: July 2002

Sterol regulatory element binding proteins (SREBPs) enhance transcription of genes encoding enzymes of cholesterol and fatty acid biosynthesis and uptake. In the current experiments, we observed a decline in the mRNA encoding one SREBP isoform, SREBP-1c, in the livers of rats that were rendered diabetic by treatment with streptozotocin. There was no change in the mRNA encoding SREBP-1a, which is derived from the same gene as SREBP-1c but uses a different promoter. The ratio of SREBP-1c:1a transcripts fell 25-fold from 5:1 in control rats to 0.2:1 in the diabetic animals. The SREBP-1c mRNA rose nearly to normal, and the 1c:1a ratio increased 17-fold when the diabetic rats were treated for 6 h with insulin. These treatments produced no change in the mRNA for SREBP-2, which is encoded by a separate gene. The SREBP-1c mRNA also fell selectively in freshly isolated rat hepatocytes and rose when the cells were treated with insulin. Considered together with recent data on hepatocytes [Foretz, M., Pacot, C., Dugal, I.,
et al.
(1999)
Mol. Cell. Biol.
19, 3760–3768], the current
in vivo
studies suggest that insulin may stimulate lipid synthesis in the liver by selectively inducing transcription of the SREBP-1c gene.
From calcium blips to calcium puffs: Theoretical analysis of the requirements for interchannel communication
Authors: Swillens Stéphane , Dupont Geneviève , Combettes Laurent , Champeil Philippe
Published: July 2002

In the cytoplasm of cells of different types, discrete clusters of inositol 1,4,5-trisphosphate-sensitive Ca
2+
channels generate Ca
2+
signals of graded size, ranging from blips, which involve the opening of only one channel, to moderately larger puffs, which result from the concerted opening of a few channels in the same cluster. These channel clusters are of unknown size or geometrical characteristics. The aim of this study was to estimate the number of channels and the interchannel distance within such a cluster. Because these characteristics are not attainable experimentally, we performed computer stochastic simulations of Ca
2+
release events. We conclude that, to ensure efficient interchannel communication, as experimentally observed, a typical cluster should contain two or three tens of inositol 1,4,5-trisphosphate-sensitive Ca
2+
channels in close contact.
Mammalian subtilisin/kexin isozyme SKI-1: A widely expressed proprotein convertase with a unique cleavage specificity and cellular localization
Authors: Seidah Nabil G. , Mowla Seyed J. , Hamelin Josée , Mamarbachi Aida M. , Benjannet Suzanne , Touré Barry B. , Basak Ajoy , Munzer Jon Scott , Marcinkiewicz Jadwiga , Zhong Mei , Barale Jean-Christophe , Lazure Claude , Murphy Richard A. , Chrétien Michel , Marcinkiewicz Mieczyslaw
Published: July 2002

Using reverse transcriptase–PCR and degenerate
oligonucleotides derived from the active-site residues of
subtilisin/kexin-like serine proteinases, we have identified a
highly conserved and phylogenetically ancestral human, rat, and mouse
type I membrane-bound proteinase called
subtilisin/kexin-isozyme-1 (SKI-1). Computer databank searches
reveal that human SKI-1 was cloned previously but with no
identified function.
In situ
hybridization
demonstrates that SKI-1 mRNA is present in most tissues and
cells. Cleavage specificity studies show that SKI-1 generates a 28-kDa
product from the 32-kDa brain-derived neurotrophic factor precursor,
cleaving at an RGLT↓SL bond. In the endoplasmic reticulum of either
LoVo or HK293 cells, proSKI-1 is processed into two membrane-bound
forms of SKI-1 (120 and 106 kDa) differing by the nature of their
N-glycosylation. Late along the secretory pathway some of the
membrane-bound enzyme is shed into the medium as a 98-kDa form.
Immunocytochemical analysis of stably transfected HK293 cells shows
that SKI-1 is present in the Golgi apparatus and within small punctate
structures reminiscent of endosomes.
In vitro
studies
suggest that SKI-1 is a Ca
2+
-dependent serine proteinase
exhibiting a wide pH optimum for cleavage of pro-brain-derived
neurotrophic factor.
The Opitz syndrome gene product, MID1, associates with microtubules
Authors: Schweiger Susann , Foerster John , Lehmann Tanja , Suckow Vanessa , Muller Yves A. , Walter Gerald , Davies Theresa , Porter Helen , van Bokhoven Hans , Lunt Peter W. , Traub Peter , Ropers Hans-Hilger
Published: July 2002

Opitz syndrome (OS) is a genetically heterogeneous disorder characterized by defects of the ventral midline, including hypertelorism, cleft lip and palate, heart defects, and mental retardation. We recently identified the gene responsible for X-linked OS. The ubiquitously expressed gene product,
MID1
, is a member of the RING finger family. These proteins are characterized by an N-terminal tripartite protein–protein interaction domain and a conserved C terminus of unknown function. Unlike other RING finger proteins for which diverse cellular functions have been proposed, the function of
MID1
is as yet undefined. By using the green fluorescent protein as a tag, we show here that
MID1
is a microtubule-associated protein that influences microtubule dynamics in
MID1
-overexpressing cells. We confirm this observation by demonstrating a colocalization of
MID1
and tubulin in subcellular fractions and the association of endogenous
MID1
with microtubules after
in vitro
assembly. Furthermore, overexpressed
MID1
proteins harboring mutations described in OS patients lack the capability to associate with microtubules, forming cytoplasmic clumps instead. These data give an idea of the possible molecular pathomechanism underlying the OS phenotype.
Evidence for a structural motif in toxins and interleukin-2 that may be responsible for binding to endothelial cells and initiating vascular leak syndrome
Authors: Baluna Roxana , Rizo Josep , Gordon Brian E. , Ghetie Victor , Vitetta Ellen S.
Published: July 2002

The dose-limiting toxicity of interleukin-2 (IL-2) and immunotoxin (IT) therapy in humans is vascular leak syndrome (VLS). VLS has a complex etiology involving damage to vascular endothelial cells (ECs), extravasation of fluids and proteins, interstitial edema, and organ failure. IL-2 and ITs prepared with the catalytic A chain of the plant toxin, ricin (RTA), and other toxins, damage human ECsin vitroandin vivo. Damage to ECs may initiate VLS; if this damage could be avoided without losing the efficacy of ITs or IL-2, larger doses could be administered. In this paper, we provide evidence that a three amino acid sequence motif, (x)D(y), in toxins and IL-2 damages ECs. Thus, when peptides from RTA or IL-2 containing this sequence motif are coupled to mouse IgG, they bind to and damage ECs bothin vitroand, in the case of RTA,in vivo. In contrast, the same peptides with a deleted or mutated sequence do not. Furthermore, the peptide from RTA attached to mouse IgG can block the binding of intact RTA to ECsin vitroandvice versa. In addition, RTA, a fragment of Pseudomonas exotoxin A (PE38-lys), and fibronectin also block the binding of the mouse IgG-RTA peptide to ECs, suggesting that an (x)D(y) motif is exposed on all three molecules. Our results suggest that deletions or mutations in this sequence or the use of nondamaging blocking peptides may increase the therapeutic index of both IL-2, as well as ITs prepared with a variety of plant or bacterial toxins.
Ligand specificity of a high-affinity binding site for lipo-chitooligosaccharidic Nod factors in
Medicago
cell suspension cultures
Authors: Gressent Frédéric , Drouillard Sophie , Mantegazza Natacha , Samain Eric , Geremia Roberto A. , Canut Hervé , Niebel Andreas , Driguez Hugues , Ranjeva Raoul , Cullimore Julie , Bono Jean-Jacques
Published: July 2002

Rhizobial lipo-chitooligosaccharides (LCOs) are signaling molecules involved in host-range recognition for the establishment of the symbiosis with leguminous plants. The major LCO of
Rhizobium meliloti
, the symbiont of
Medicago
plants contains four or five
N
-acetylglucosamines, O-acetylated and N-acylated with a C16:2 fatty acid on the terminal nonreducing sugar and O-sulfated on the reducing sugar. In this paper, the ligand specificity of a high-affinity binding site (Nod factor binding site 2 or NFBS2), enriched in a plasma membrane-enriched fraction of
Medicago
cell suspension cultures, is reported. By using chemically synthesized LCOs, the role of structural elements, important for symbiotic activities, as recognition motifs for NFBS2 was determined. The results show that the substitutions on the nonreducing sugar of the LCOs (the
O
-acetate group, the fatty acid, and the hydroxyl group on the C
4
of the sugar) are determinants for high-affinity binding to NFBS2. In contrast, the sulfate group, which is necessary for all biological activities on
Medicago
, is not discriminated by NFBS2. However, the reducing sugar of the LCO seems to interact with NFBS2, because ligand binding is affected by the reduction of the free anomeric carbon and depends on the number of
N
-acetyl glucosamine residues. These results suggest that the recognition of the LCOs by NFBS2 is mediated by structural elements in both the lipid and oligosaccharidic moities, but not by the sulfate group.
Phosphorylation of the
Neurospora
clock protein FREQUENCY determines its degradation rate and strongly influences the period length of the circadian clock
Authors: Liu Yi , Loros Jennifer , Dunlap Jay C.
Published: July 2002

Under free running conditions, FREQUENCY (FRQ) protein, a central component of the
Neurospora
circadian clock, is progressively phosphorylated, becoming highly phosphorylated before its degradation late in the circadian day. To understand the biological function of FRQ phosphorylation, kinase inhibitors were used to block FRQ phosphorylation
in vivo
and the effects on FRQ and the clock observed. 6-dimethylaminopurine (a general kinase inhibitor) is able to block FRQ phosphorylation
in vivo,
reducing the rate of phosphorylation and the degradation of FRQ and lengthening the period of the clock in a dose-dependent manner. To confirm the role of FRQ phosphorylation in this clock effect, phosphorylation sites in FRQ were identified by systematic mutagenesis of the FRQ ORF. The mutation of one phosphorylation site at Ser-513 leads to a dramatic reduction of the rate of FRQ degradation and a very long period (>30 hr) of the clock. Taken together, these data strongly suggest that FRQ phosphorylation triggers its degradation, and the degradation rate of FRQ is a major determining factor for the period length of the
Neurospora
circadian clock.
Why are angles misperceived?
Authors: Nundy Surajit , Lotto Beau , Coppola David , Shimpi Amita , Purves Dale
Published: July 2002

Although it has long been apparent that observers tend to overestimate the magnitude of acute angles and underestimate obtuse ones, there is no consensus about why such distortions are seen. Geometrical modeling combined with psychophysical testing of human subjects indicates that these misperceptions are the result of an empirical strategy that resolves the inherent ambiguity of angular stimuli by generating percepts of the past significance of the stimulus rather than the geometry of its retinal projection.
G protein-coupled receptor kinase-5 regulates thrombin-activated signaling in endothelial cells
Authors: Tiruppathi Chinnaswamy , Yan Weihong , Sandoval Raudel , Naqvi Tabassum , Pronin Alexey N. , Benovic Jeffery L. , Malik Asrar B.
Published: July 2002

We studied the function of G protein-coupled receptor kinases (GRKs) in the regulation of thrombin-activated signaling in endothelial cells. GRK2, GRK5, and GRK6 isoforms were expressed predominantly in endothelial cells. The function of these isoforms was studied by expressing wild-type and dominant negative (dn) mutants in endothelial cells. We determined the responses to thrombin, which activates intracellular signaling in endothelial cells by cleaving the NH
2
terminus of the G protein-coupled proteinase-activated receptor-1 (PAR-1). We measured changes in phosphoinositide hydrolysis and intracellular Ca
2+
concentration ([Ca
2+
]
i
) in response to thrombin as well as the state of endothelial activation. In the latter studies, the transendothelial monolayer electrical resistance, a measure of the loss of endothelial barrier function, was measured in real time. Of the three isoforms, GRK5 overexpression was selective in markedly reducing the thrombin-activated phosphoinositide hydrolysis and increased [Ca
2+
]
i
. GRK5 overexpression also inhibited the thrombin-induced decrease in endothelial monolayer resistance by 75%. These effects of GRK5 overexpression occurred in association with the specific increase in the thrombin-induced phosphorylation of PAR-1. In contrast to the effects of GRK5 overexpression, the expression of the dn-GRK5 mutant produced a long-lived increase in [Ca
2+
]
i
in response to thrombin, whereas dn-GRK2 had no effect. These results indicate the crucial role of the GRK5 isoform in the mechanism of thrombin-induced desensitization of PAR-1 in endothelial cells.
Species-barrier-independent prion replication in apparently resistant species
Authors: Hill Andrew F. , Joiner Susan , Linehan Jackie , Desbruslais Melanie , Lantos Peter L. , Collinge John
Published: July 2002

Transmission of prions between mammalian species is thought to be limited by a “species barrier,” which depends on differences in the primary structure of prion proteins in the infecting inoculum and the host. Here we demonstrate that a strain of hamster prions thought to be nonpathogenic for conventional mice leads to prion replication to high levels in such mice but without causing clinical disease. Prions pathogenic in both mice and hamsters are produced. These results demonstrate the existence of subclinical forms of prion infection with important public health implications, both with respect to iatrogenic transmission from apparently healthy humans and dietary exposure to cattle and other species exposed to bovine spongiform encephalopathy prions. Current definitions of the species barrier, which have been based on clinical end-points, need to be fundamentally reassessed.
A new view of language acquisition
Authors: Kuhl Patricia K.
Published: July 2002

At the forefront of debates on language are new data demonstrating infants' early acquisition of information about their native language. The data show that infants perceptually “map” critical aspects of ambient language in the first year of life before they can speak. Statistical properties of speech are picked up through exposure to ambient language. Moreover, linguistic experience alters infants' perception of speech, warping perception in the service of language. Infants' strategies are unexpected and unpredicted by historical views. A new theoretical position has emerged, and six postulates of this position are described.
Speech-like cerebral activity in profoundly deaf people processing signed languages: Implications for the neural basis of human language
Authors: Petitto Laura Ann , Zatorre Robert J. , Gauna Kristine , Nikelski E. J. , Dostie Deanna , Evans Alan C.
Published: July 2002

For more than a century we have understood that our brain's left hemisphere is the primary site for processing language, yet why this is so has remained more elusive. Using positron emission tomography, we report cerebral blood flow activity in profoundly deaf signers processing specific aspects of sign language in key brain sites widely assumed to be unimodal speech or sound processing areas: the left inferior frontal cortex when signers produced meaningful signs, and the planum temporale bilaterally when they viewed signs or meaningless parts of signs (sign-phonetic and syllabic units). Contrary to prevailing wisdom, the planum temporale may not be exclusively dedicated to processing speech sounds, but may be specialized for processing more abstract properties essential to language that can engage multiple modalities. We hypothesize that the neural tissue involved in language processing may not be prespecified exclusively by sensory modality (such as sound) but may entail polymodal neural tissue that has evolved unique sensitivity to aspects of the patterning of natural language. Such neural specialization for aspects of language patterning appears to be neurally unmodifiable in so far as languages with radically different sensory modalities such as speech and sign are processed at similar brain sites, while, at the same time, the neural pathways for expressing and perceiving natural language appear to be neurally highly modifiable.
The molecular physiology of heavy metal transport in the Zn/Cd hyperaccumulatorThlaspi caerulescens
Authors: Pence Nicole S. , Larsen Paul B. , Ebbs Stephen D. , Letham Deborah L. D. , Lasat Mitch M. , Garvin David F. , Eide David , Kochian Leon V.
Published: July 2002

An integrated molecular and physiological investigation of the fundamental mechanisms of heavy metal accumulation was conducted inThlaspi caerulescens, a Zn/Cd-hyperaccumulating plant species. A heavy metal transporter cDNA,ZNT1, was cloned fromT. caerulescensthrough functional complementation in yeast and was shown to mediate high-affinity Zn2+uptake as well as low-affinity Cd2+uptake. It was found that this transporter is expressed at very high levels in roots and shoots of the hyperaccumulator. A study ofZNT1expression and high-affinity Zn2+uptake in roots ofT. caerulescensand in a related nonaccumulator,Thlaspi arvense, showed that alteration in the regulation ofZNT1gene expression by plant Zn status results in the overexpression of this transporter and in increased Zn influx in roots of the hyperaccumulatingThlaspispecies. These findings yield insights into the molecular regulation and control of plant heavy metal and micronutrient accumulation and homeostasis, as well as provide information that will contribute to the advancement of phytoremediation by the future engineering of plants with improved heavy metal uptake and tolerance.
Patterns of spread in biological invasions dominated by long-distance jump dispersal: Insights from Argentine ants
Authors: Suarez Andrew V. , Holway David A. , Case Ted J.
Published: July 2002

Invading organisms may spread through local movements (giving rise to a diffusion-like process) and by long-distance jumps, which are often human-mediated. The local spread of invading organisms has been fit with varying success to models that couple local population growth with diffusive spread, but to date no quantitative estimates exist for the relative importance of local dispersal relative to human-mediated long-distance jumps. Using a combination of literature review, museum records, and personal surveys, we reconstruct the invasion history of the Argentine ant (Linepithema humile), a widespread invasive species, at three spatial scales. Although the inherent dispersal abilities of Argentine ants are limited, in the last century, human-mediated dispersal has resulted in the establishment of this species on six continents and on many oceanic islands. Human-mediated jump dispersal has also been the primary mode of spread at a continental scale within the United States. The spread of the Argentine ant involves two discrete modes. Maximum distances spread by colonies undergoing budding reproduction averaged 150 m/year, whereas annual jump-dispersal distances averaged three orders of magnitude higher. Invasions that involve multiple dispersal processes, such as those documented here, are undoubtedly common. Detailed data on invasion dynamics are necessary to improve the predictive power of future modeling efforts.
A mouse model of multiple endocrine neoplasia, type 1, develops multiple endocrine tumors
Authors: Crabtree Judy S. , Scacheri Peter C. , Ward Jerrold M. , Garrett-Beal Lisa , Emmert-Buck Michael R. , Edgemon Keith A. , Lorang Dominique , Libutti Steven K. , Chandrasekharappa Settara C. , Marx Stephen J. , Spiegel Allen M. , Collins Francis S.
Published: July 2002

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant
cancer syndrome, characterized primarily by multiple tumors in the
parathyroid glands, endocrine pancreas, and anterior pituitary. Other
tumors, including gastrinoma, carcinoid, adrenal cortical tumors,
angiofibroma, collagenoma, and lipoma, also occur in some patients.
Individuals with MEN1 almost always have loss-of-function mutations in
the
MEN1
gene on chromosome 11, and endocrine tumors
arising in these patients usually show somatic loss of the remaining
wild-type allele. To examine the role of
MEN1
in tumor
formation, a mouse model was generated through homologous recombination
of the mouse homolog
Men1
. Homozygous mice die
in
utero
at embryonic days 11.5–12.5, whereas heterozygous mice
develop features remarkably similar to those of the human disorder. As
early as 9 months, pancreatic islets show a range of lesions from
hyperplasia to insulin-producing islet cell tumors, and parathyroid
adenomas are also frequently observed. Larger, more numerous tumors
involving pancreatic islets, parathyroids, thyroid, adrenal cortex, and
pituitary are seen by 16 months. All of the tumors tested to date show
loss of the wild-type
Men1
allele, further supporting
its role as a tumor suppressor gene.
Analysis of gene expression profiles in normal and neoplastic ovarian tissue samples identifies candidate molecular markers of epithelial ovarian cancer
Authors: Welsh John B. , Zarrinkar Patrick P. , Sapinoso Lisa M. , Kern Suzanne G. , Behling Cynthia A. , Monk Bradley J. , Lockhart David J. , Burger Robert A. , Hampton Garret M.
Published: July 2002

Epithelial ovarian cancer is the leading cause of death from
gynecologic cancer, in part because of the lack of effective early
detection methods. Although alterations of several genes, such as
c-erb-B2, c-myc
, and
p53
, have been
identified in a significant fraction of ovarian cancers, none of these
mutations are diagnostic of malignancy or predictive of tumor behavior
over time. Here, we used oligonucleotide microarrays with probe sets
complementary to >6,000 human genes to identify genes whose expression
correlated with epithelial ovarian cancer. We extended current
microarray technology by simultaneously hybridizing ovarian RNA samples
in a highly parallel manner to a single glass wafer containing 49
individual oligonucleotide arrays separated by gaskets within a
custom-built chamber (termed “array-of-arrays”). Hierarchical
clustering of the expression data revealed distinct groups of samples.
Normal tissues were readily distinguished from tumor tissues, and
tumors could be further subdivided into major groupings that correlated
both to histological and clinical observations, as well as cell
type-specific gene expression. A metric was devised to identify genes
whose expression could be considered ideal for molecular determination
of epithelial ovarian malignancies. The list of genes generated by this
method was highly enriched for known markers of several epithelial
malignancies, including ovarian cancer. This study demonstrates the
rapidity with which large amounts of expression data can be generated.
The results highlight important molecular features of human ovarian
cancer and identify new genes as candidate molecular markers.
Urban Form and Travel Behaviour: Micro-level Household Attributes and Residential Context
Authors: Dieleman Frans M. , Dijst Martin , Burghouwt Guillaume
Published: July 2002

Many countries now have policies to reduce distances travelled by private car and to favour the use of public transport, cycling and walking. The development of compact urban forms and the design of urban communities which favour walking are seen as particularly effective strategies for reducing car dependency. The factors which determine travel behaviour are not fully understood, so that effective policies influencing travel patterns are difficult to formulate. Apart from urban form and design, personal attributes and circumstances have an impact on modal choice and distances travelled. People with higher incomes are more likely to own and use a private car than low-income households. Families with children use cars more often than one-person households. The purpose of a trip-work, shopping and leisure—also influences travel mode and distance. We used the Netherlands National Travel Survey (OVG) to explore some of these relationships in more depth. The relative importance of personal attributes and the characteristics of residential environments as determinants of modal choice and travel distance were explored. Both sets of factors maintain a clear, strong relationship with travel behaviour in multivariate models of travel behaviour.
Roma of the Former Yugoslavia*
Authors: Latham Judith
Published: July 2002

Throughout Central and Eastern Europe, the collapse of communism has led to an unleashing of ethnic strife and a worsening of the economic conditions of the Roma, who by any measurement occupy the lowest rung of the social ladder. In the former Yugoslavia, the situation has been aggravated enormously by war, rampant nationalism, forced emigration, ethnic cleansing, and economic sanctions. The nearly four-year war in the region took a heavy toll on all the successor states except Slovenia.
The Ecology of Mother-Infant Interaction in Euro-American and Immigrant Central American Families Living in the United States
Authors: Fracasso Maria P. , Lamb Michael E. , Schölmerich Axel , Leyendecker Birgit
Published: July 2002

In an attempt to explore cultural and subcultural similarities and variations in the patterns of child care, two culturally and economically distinct groups were studied. Twenty-one 3-month-old infants had well-educated Euro-American mothers and another 17 had recently migrated Central American mothers. Observations of parent-infant interaction and behaviour were conducted at home throughout the day to ensure coverage of complete 12-hour cycles. Descriptive analyses revealed remarkable similarities and few differences in the everyday experiences of infants in these two diverse groups. Both groups of mothers spent most of their time playing with, feeding, or caring for their infants. Fathers spent little time with their infants during the day but their presence affected the amount of time spent in various contexts, with significantly less object play occurring when the fathers were present. Mother and infant vocalisations and mutual attention occurred more frequently during social interaction and caretaking than in bouts of feeding. These descriptive profiles expand our basic understanding of infants’ everyday experiences in diverse subcultural groups.
Turmoil for Adoptees during their Adolescence?
Authors: Hoksbergen René A.C.
Published: July 2002

During the last two decades in the Netherlands foreign adoptions have increased compared to domestic adoptions. In this paper, research studies concerning causes and characteristics of problem behaviour of adopted adolescents are discussed. Adopted adolescents, in particular, face more emotional problems compared to their nonadopted peers, as evidenced in parent reports. However, on the basis of reports from adopted adolescents, coping with four of Havighurst’s developmental tasks is satisfactory. However, adopted adolescents report more feelings of insecurity and emotional tension concerning their gender experience with regard to their physical appearance compared to their Dutch peers. Based on the research reviewed and clinical experience at the Utrecht Adoption Centre, risk factors in adoption are summarised.
Understanding Age Differences in Memory: Disentangling Conscious and Unconscious Processes
Authors: Anooshian Linda J.
Published: July 2002

Distinct processes involved in memory development were explored by obtaining separate measures of preschoolers’ and college students’ use of familiarity and conscious recollection in picture recognition. In each of two testing sessions (separated by one week; with different video materials), participants viewed pictures in the context of hearing a story. Further phases of the experimental procedure were based on process dissociation, a methodology that provides separate estimates of the contributions of conscious recollection and familiarity. Consistent with existing literature on separate implicit and explicit tasks, the results revealed a reliable difference between preschoolers and adults for measures of conscious recollection. In contrast, but also consistent with past research with implicit memory tasks, no developmental differences were observed for familiarity estimates. Results were discussed in the context of controversy regarding the best procedures for measuring different memory processes.
How many standard drinks are there in a glass of wine?
Authors: BANWELL CATHY
Published: July 2002

This small study investigates how much alcohol women consume when they have a glass of wine. Hotels in an inner city suburb of Melbourne were visited and their most commonly used wine glass was measured. Three major glass distributors and the Australian Hotels Association were asked about the size of commonly used wine glasses. Eighty‐six women measured and recorded the amount of alcohol they drank in a 2‐week prospective beverage diary. This study shows that, on average, wine glasses used in licensed premises such as hotels are larger than a standard drink. When at home participants, on average, drank more than a standard drink when consuming wine, champagne, spirits or liqueurs, but they drank less than a standard drink when drinking beer, cider and fortified wine. Wine drinkers, who are often women, cannot rely solely on counting their glasses of wine to keep them below the recommended number of standard drinks when in social situations, such as at hotels and private dwellings.
Axonal Neuregulin Signals Cells of the Oligodendrocyte Lineage through Activation of HER4 and Schwann Cells through HER2 and HER3
Authors: Vartanian Timothy , Goodearl Andrew , Viehöver Andrea , Fischbach Gerald
Published: July 2002

We are interested in the signaling between axons and glia that leads to myelination and maintenance of the myelin internode, and we have focused on the role of neuregulins and their receptors. Neuregulins are a family of ligands that includes heregulin, neu differentiation factor, glial growth factor, and the acetylcholine receptor–inducing activity. Three signal transducing transmembrane receptors for neuregulins, which bear significant homology to the EGF receptor, are currently known: HER2 (erbB2), HER3 (erbB3), and HER4 (erbB4). We have found that oligodendrocite–type II astrocyte (O2A) progenitor cells and mature oligodendrocytes express HER2 and HER4 but no HER3. Schwann cells express HER2 and HER3 but little HER4. In O2A progenitor cells and oligodendrocytes, recombinant neuregulin induces the rapid tyrosine phosphorylation of only HER4. HER2 is not phosphorylated in cells of the oligodendrocyte lineage, but a physical interaction between HER2 and HER4 was detected in coimmunoprecipitation experiments. In Schwann cells, neuregulin induces the phosphorylation of both HER2 and HER3. Coimmunoprecipitation experiments indicate that receptor activation in Schwann cells results in the formation of HER2:HER3 heterodimers. Neuregulin localized immunocytochemically was present on neurites of cultured dorsal root ganglion neurons, and it was released into the medium in a form that promoted receptor tyrosine phosphorylation. Neuregulins therefore meet important criteria expected of molecules involved in axonal-glial signaling. The use of unique neuregulin receptor combinations in oligodendrocytes and Schwann cells likely results in recruitment of different signaling pathways and thus provides a basis for different biological responses.
The Axonal Membrane Protein Caspr, a Homologue of Neurexin IV, Is a Component of the Septate-like Paranodal Junctions That Assemble during Myelination
Authors: Einheber Steven , Zanazzi George , Ching William , Scherer Steven , Milner Teresa A. , Peles Elior , Salzer James L.
Published: July 2002

We have investigated the potential role of contactin and contactin-associated protein (Caspr) in the axonal–glial interactions of myelination. In the nervous system, contactin is expressed by neurons, oligodendrocytes, and their progenitors, but not by Schwann cells. Expression of Caspr, a homologue of Neurexin IV, is restricted to neurons. Both contactin and Caspr are uniformly expressed at high levels on the surface of unensheathed neurites and are downregulated during myelination in vitro and in vivo. Contactin is downregulated along the entire myelinated nerve fiber. In contrast, Caspr expression initially remains elevated along segments of neurites associated with nascent myelin sheaths. With further maturation, Caspr is downregulated in the internode and becomes strikingly concentrated in the paranodal regions of the axon, suggesting that it redistributes from the internode to these sites. Caspr expression is similarly restricted to the paranodes of mature myelinated axons in the peripheral and central nervous systems; it is more diffusely and persistently expressed in gray matter and on unmyelinated axons. Immunoelectron microscopy demonstrated that Caspr is localized to the septate-like junctions that form between axons and the paranodal loops of myelinating cells. Caspr is poorly extracted by nonionic detergents, suggesting that it is associated with the axon cytoskeleton at these junctions. These results indicate that contactin and Caspr function independently during myelination and that their expression is regulated by glial ensheathment. They strongly implicate Caspr as a major transmembrane component of the paranodal junctions, whose molecular composition has previously been unknown, and suggest its role in the reciprocal signaling between axons and glia.
The 13-kD FK506 Binding Protein, FKBP13, Interacts with a Novel Homologue of the Erythrocyte Membrane Cytoskeletal Protein 4.1
Authors: Walensky Loren D. , Gascard Philippe , Field Michael E. , Blackshaw Seth , Conboy John G. , Mohandas Narla , Snyder Solomon H.
Published: July 2002

We have identified a novel generally expressed homologue of the erythrocyte membrane cytoskeletal protein 4.1, named 4.1G, based on the interaction of its COOH-terminal domain (CTD) with the immunophilin FKBP13. The 129-amino acid peptide, designated 4.1G–CTD, is the first known physiologic binding target of FKBP13. FKBP13 is a 13-kD protein originally identified by its high affinity binding to the immunosuppressant drugs FK506 and rapamycin (Jin, Y., M.W. Albers, W.S. Lane, B.E. Bierer, and S.J. Burakoff. 1991. Proc. Natl. Acad. Sci. USA. 88:6677– 6681); it is a membrane-associated protein thought to function as an ER chaperone (Bush, K.T., B.A. Henrickson, and S.K. Nigam. 1994. Biochem. J. [Tokyo]. 303:705–708). We report the specific association of FKBP13 with 4.1G–CTD based on yeast two-hybrid, in vitro binding and coimmunoprecipitation experiments. The histidyl-proline moiety of 4.1G–CTD is required for FKBP13 binding, as indicated by yeast experiments with truncated and mutated 4.1G–CTD constructs. In situ hybridization studies reveal cellular colocalizations for FKBP13 and 4.1G–CTD throughout the body during development, supporting a physiologic role for the interaction. Interestingly, FKBP13 cofractionates with the red blood cell homologue of 4.1 (4.1R) in ghosts, inside-out vesicles, and Triton shell preparations. The identification of FKBP13 in erythrocytes, which lack ER, suggests that FKBP13 may additionally function as a component of membrane cytoskeletal scaffolds.
Accelerated Nerve Regeneration Mediated by Schwann Cells Expressing a Mutant Form of the POU Protein SCIP
Authors: Gondré Marjorie , Burrola Patrick , Weinstein David E.
Published: July 2002

After injury, the peripheral nervous system (PNS) is capable of full regeneration and recovery of function. Many molecular events that are the hallmarks of the regenerating PNS are recapitulations of developmental processes. The expression of one such molecule, the POU transcription factor suppressed cAMP-inducible POU protein (SCIP), is required for the establishment of normal nerves and is reexpressed during regeneration. Here we describe markedly accelerated regeneration and hypertrophy of both myelin and axons in transgenic mice that express an amino-terminal deletion of the SCIP molecule. This mutant SCIP molecule retains the POU-specific and POU homeodomain moieties, which allow for both DNA binding and some protein–protein interaction. We demonstrate that the transgene indirectly effects dramatic axonal changes. This is the first demonstration of a genetically controlled acceleration of neural regeneration.
Myogenin Induces a Shift of Enzyme Activity from Glycolytic to Oxidative Metabolism in Muscles of Transgenic Mice
Authors: Hughes Simon M. , Chi Maggie M.-Y. , Lowry Oliver H. , Gundersen Kristian
Published: July 2002

Physical training regulates muscle metabolic and contractile properties by altering gene expression. Electrical activity evoked in muscle fiber membrane during physical activity is crucial for such regulation, but the subsequent intracellular pathway is virtually unmapped. Here we investigate the ability of myogenin, a muscle-specific transcription factor strongly regulated by electrical activity, to alter muscle phenotype. Myogenin was overexpressed in transgenic mice using regulatory elements that confer strong expression confined to differentiated post-mitotic fast muscle fibers. In fast muscles from such mice, the activity levels of oxidative mitochondrial enzymes were elevated two- to threefold, whereas levels of glycolytic enzymes were reduced to levels 0.3–0.6 times those found in wild-type mice. Histochemical analysis shows widespread increases in mitochondrial components and glycogen accumulation. The changes in enzyme content were accompanied by a reduction in fiber size, such that many fibers acquired a size typical of oxidative fibers. No change in fiber type-specific myosin heavy chain isoform expression was observed. Changes in metabolic properties without changes in myosins are observed after moderate endurance training in mammals, including humans. Our data suggest that myogenin regulated by electrical activity may mediate effects of physical training on metabolic capacity in muscle.
Intron-independent Association of Splicing Factors with Active Genes
Authors: Jolly Caroline , Vourc'h Claire , Robert-Nicoud Michel , Morimoto Richard I.
Published: July 2002

The cell nucleus is organized as discrete domains, often associated with specific events involved in chromosome organization, replication, and gene expression. We have examined the spatial and functional relationship between the sites of heat shock gene transcription and the speckles enriched in splicing factors in primary human fibroblasts by combining immunofluorescence and fluorescence in situ hybridization (FISH). The hsp90α and hsp70 genes are inducibly regulated by exposure to stress from a low basal level to a high rate of transcription; additionally the hsp90α gene contains 10 introns whereas the hsp70 gene is intronless. At 37°C, only 30% of hsp90α transcription sites are associated with speckles whereas little association is detected with the hsp70 gene, whose constitutive expression is undetectable relative to the hsp90α gene. Upon exposure of cells to heat shock, the heavy metal cadmium, or the amino acid analogue azetidine, transcription at the hsp90α and hsp70 gene loci is strongly induced, and both hsp transcription sites become associated with speckles in >90% of the cells. These results reveal a clear disconnection between the presence of intervening sequences at specific gene loci and the association with splicing factor–rich regions and suggest that subnuclear structures containing splicing factors are associated with sites of transcription.
Morphological Differentiation of Oligodendrocytes Requires Activation of Fyn Tyrosine Kinase
Authors: Osterhout Donna J. , Wolven Amy , Wolf Rebecca M. , Resh Marilyn D. , Chao Moses V.
Published: July 2002

In the central nervous system, myelination of axons occurs when oligodendrocyte progenitors undergo terminal differentiation and initiate process formation and axonal ensheathment. Although it is hypothesized that neuron-oligodendrocyte contact initiates this process, the molecular signals are not known. Here we find that Fyn tyrosine kinase activity is upregulated very early during oligodendrocyte progenitor cell differentiation. Concomitant with this increase is the appearance of several tyrosine phosphorylated proteins present only in differentiated cells. The increased tyrosine kinase activity is specific to Fyn, as other Src family members are not active in oligodendrocytes. To investigate the function of Fyn activation on differentiation, we used Src family tyrosine kinase inhibitors, PP1 and PP2, in cultures of differentiating oligodendrocyte progenitors. Treatment of progenitors with these compounds prevented activation of Fyn and reduced process extension and myelin membrane formation. This inhibition was reversible and not observed with related inactive analogues. A similar effect was observed when a dominant negative Fyn was introduced in progenitor cells. These findings strongly suggest that activation of Fyn is an essential signaling component for the morphological differentiation of oligodendrocytes.
Nuclear Organization of Mammalian Genomes
Authors: Sadoni Nicolas , Langer Sabine , Fauth Christine , Bernardi Giorgio , Cremer Thomas , Turner Bryan M. , Zink Daniele
Published: July 2002

We investigated the nuclear higher order compartmentalization of chromatin according to its replication timing (Ferreira et al. 1997) and the relations of this compartmentalization to chromosome structure and the spatial organization of transcription. Our aim was to provide a comprehensive and integrated view on the relations between chromosome structure and functional nuclear architecture. Using different mammalian cell types, we show that distinct higher order compartments whose DNA displays a specific replication timing are stably maintained during all interphase stages. The organizational principle is clonally inherited. We directly demonstrate the presence of polar chromosome territories that align to build up higher order compartments, as previously suggested (Ferreira et al. 1997). Polar chromosome territories display a specific orientation of early and late replicating subregions that correspond to R- or G/C-bands of mitotic chromosomes. Higher order compartments containing G/C-bands replicating during the second half of the S phase display no transcriptional activity detectable by BrUTP pulse labeling and show no evidence of transcriptional competence. Transcriptionally competent and active chromatin is confined to a coherent compartment within the nuclear interior that comprises early replicating R-band sequences. As a whole, the data provide an integrated view on chromosome structure, nuclear higher order compartmentalization, and their relation to the spatial organization of functional nuclear processes.