bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic mapping of Prm-1, Igl-1, Smst, Mtv-6, Sod-1, and Ets-2and localization of the Down syndrome region on mouse chromosome 16
Authors: Reeves R.H. , Gallahan D. , O’Hara B.F. , Callahan R. , Gearhart J.D.
Published: May 2008

Molecular probes were used as markers in the backcross (Czech II × BALB/cPt) × Czech II to determine the positions of six genes on mouse chromosome 16 (MMU 16). The order of the genes mapped is (centromere), protamine-1 (Prm-1), immunoglobulin λ1 light chain (Igl-1), preprosomatostatin (Smst), an endogenous mouse mammary tumor virus locus (Mtv-6), and two more distal sequences, superoxide dis-mutase, cytoplasmic form (Sod-1), and the proto-oncogene sequence Ets-2. The largest recombination frequency between any two adjacent markers is 24 cM, and thus the position of any marker on MMU 16 that is polymorphic between these two strains can be readily determined in this backcross. A region of MMU 16 which corresponds to the Down syndrome region of human chromosome 21 is located near the distal end of the chromosome.
Sex linkage of muscle creatine kinase in Harris’ hawks
Authors: Morizot D.C. , Bednarz J.C. , Ferrell R.E.
Published: May 2008

Starch gel electrophoresis of Harris’ hawk muscle samples revealed an unusual association of enzyme phenotypes and sex: all females were heterozygous and all males were homozygous. Enzyme activities were not significantly different between sexes. Since birds are characterized by female heterogamety (ZZ males, ZW females), these results are interpreted as suggesting sex linkage with the expression of both Z- and W-linked alleles.
Regional localization of three probes closely linked to the cystic fibrosis locus by deletion analysis
Authors: Wainwright B.J. , Scambler P.J. , Williamson R.
Published: May 2008

A cell line hemizygous for a deletion of the human chromosome region 7q22→q32 was used for fine mapping three probes closely linked to the cystic fibrosis locus. The three markers, J.3.11, 7c22, and met, were all found to be deleted from the region 7q22→q32. This finding, in combination with previously published mapping data, led to the assignment of J3.11 to 7q22.
The nature of the 1;29 translocation in cattle as revealed by synaptonemal complex analysis using electron microscopy
Authors: Switoński M. , Gustavsson I. , Plöen L.
Published: May 2008

Synaptonemal complex analyses were carried out by electron microscopy on surface-spread spermatocytes of one normal bull and two bulls that were heterozygous for the so-called 1;29 translocation. The autosomal bivalents of the normal karyotype, which could be arranged by size in a series, demonstrated kinetochores at the terminally located attachment plaques. One autosomal bivalent was clearly larger than the rest and apparently consisted of the long arm of the 1;29 translocation. The 1;29 translocation was the longest autosome in the set and had a kinetochore in a subtelocentric position. Some of the autosome pairs had nucleolus organizer regions in telomeric regions. The X and Y chromosomes, which were not paired at zygotene, demonstrated association in a very short segment at early pachytene; in no cells could a synaptonemal complex be seen between the X and Y. Very often the sex chromosomes were dissociated. At zygotene, a few, usually large, bivalents were unpaired proximally. This always also involved the proximal parts of the arms of the 1;29 translocation and their normal homologs. At early pachytene, the 1;29 trivalent, although to a less extensive degree, was also unpaired in the pericentric region. Configurations in which one chromosome, either 1 or 29, was completely paired with its corresponding arm in the 1;29 translocation chromosome also occurred. When unpaired proximally, the size of chromosome 1 agreed fairly well with the size of its corresponding arm, but the size of chromosome 29 was considerably larger than the corresponding arm of the 1;29 translocation chromosome. During late zygotene and early pachytene, the percent difference between chromosome 29 and its corresponding arm decreased, and at mid and late pachytene there had been a complete synaptic adjustment. The size difference and pairing behavior indicated that a deletion of the kinetochore and the most proximal segment of chromosome 29 had preceded the fusion with chromosome 1 into the 1;29 translocation. The unique structural appearance of the 1;29 translocation chromosome compared to that of other centric fusion translocations in cattle lends support to the theory of a monophyletic origin of the 1;29 translocation. The importance of the pairing behavior observed in governing recombination and chromosome disjunction is briefly discussed.
Localization and linkage of three polymorphic DNA sequences on human chromosome 20
Authors: Goodfellow P.J. , Duncan A.M.V. , Farrer L.A. , Holden J.J.A. , White B.N. , Kidd J.R. , Kidd K.K. , Simpson N.E.
Published: May 2008

The D20S6 locus has been sublocalized by in situ hybridization using the pD3H12 probe to human chromosome band 20p12 and the D20S4 locus using the pMSl-27 probe to 20q13.2. A rare new restriction fragment length polymorphism detected in MspI-digested DNA by the pMSl-27 probe is reported. Linkage studies in nine families have shown that the D20S6 locus is linked to D20S5 (formerly mapped to 20p12 by in situ hybridization) with a maximum likelihood estimate of 0.07 for the recombination frequency (lod score = 9.07) and a confidence interval of 0.02 to 0.14. Estimated recombination frequencies were similar in males and females. Using both two- and multipoint analyses, linkage of D20S4 with the D20S5 and D20S6 loci was excluded and the suggested order for the three loci on chromosome 20 is D20S5-D20S6-centromere-D20S4. D20S5 and D20S6 are very useful markers for linkage studies because of their close proximity and reasonably good polymorphic information content values.
Expression of fragile X in human-mouse somatic cell hybrids
Authors: Lin M.S. , Shimanuki K. , Wilson M.G.
Published: May 2008

Fragile X expression was studied in human-mouse cell hybrids prepared from lymphocytes and fibroblasts obtained from a mentally retarded male. The patient showed a fragile X in 29–35.5% of his lymphocytes in medium 199 (M199) and in M199 plus fluorodeoxyuridine (FdU). One lymphocyte hybrid clone showed no expression in M199 and low expression in M199 + FdU. The other lymphocyte hybrid clone showed significantly increased expression in both media, comparable to levels in the parental cells. Fibroblast cultures from the patient showed no fragile X expression in M199 and 17% expression in M199 + FdU. Fragile X expression was also found in fibroblast hybrid clones in M199 and was significantly enhanced by the addition of FdU. Fragile X expression in one clone was consistently lower than in the other two clones and in the parental fibroblasts. Our results indicate that the level of fragile X expression varies in the hybrid clones, since frequencies similar to those of parental cells and suppressed frequencies were found. The presence or absence of a specific human chromosome did not correlate with the level of fragile X expression.
Re-evaluation of the sublocalization of esterase D and its relation to the retinoblastoma locus by in situ hybridization
Authors: Duncan A.M.V. , Morgan C. , Gallie B.L. , Phillips R.A. , Squire J.
Published: May 2008

In situ hybridization of a cDN A probe for the esterase D gene (ESD) was carried out on human chromosomes. The probe hybridized most strongly to 13q14.2 and 13q14.3. This observation raises doubts concerning the most recently published assignment of ESD to 13q14.1. A deletion in an individual with retinoblastoma was reported to separate the closely linked ESD and retinoblastoma (RBI) loci, placing ESD proximal to RBI. Quantitative in situ hybridization studies of this deletion do not confirm this interpretation. Rather, they suggest that ESD is missing from the deleted chromosome 13 and duplicated on the normal homolog. From these findings, we conclude that the deletion in this individual cannot be used to determine the orientation nor the sublocalization of ESD and RBI within the 13q14 region.
Heterochromatic variation in Cebus apella (Cebidae, Platyrrhini) of different geographic regions
Authors: Matayoshi T. , Seuánez H.N. , Nasazzi N. , Nagle C. , Armada J.L. , Freitas L. , Alves G. , Barroso C.M. , Howlin E.
Published: May 2008

Different kinds of constitutive heterochromatin variation were observed in 72 specimens of Cebus apella, belonging to five distinct subspecies, captured in four geographic regions of South America. One particular chromosome type, affecting pair 19, was found to be exclusive of one subspecies (Cebus apella paraguayanus) and to have a distribution significantly different from that expected at equilibrium. Conversely, some other chromosome polymorphisms were more widespread, with distributions compatible with equilibrium. Other variant types, probably resulting from paracentric inversions involving both heterochromatin and euchromatin, were rarer and restricted to single specimens. Finally, a distinctive chromosome type 11 was found to be exclusive of one subspecies (Cebus apella xanthosternos), where it appeared as a fixed trait.
A Robertsonian polymorphism in pink salmon (Oncorhynchus gorbuscha) involving the nucleolar organizer region
Authors: Phillips R.B. , Kapuscinksi A.R.D.
Published: May 2008

A chromosome polymorphism involving a Robertsonian rearrangement has been found for two consecutive years in pink salmon from Lake Superior. Although the majority of the fish have a diploid number of 52, as previously reported for Oncorhynchus gorbuscha, 10–15% of the population have 2n = 53, in which one of the metacentric chromosomes has apparently undergone fission. The chromosome pair involved is the pair which contains the nucleolar organizer region (NOR) which is normally found adjacent to the centromere. In all of the individuals with 53 chromosomes, there is a small, acrocentric chromosome representing the short arm of the normal metacentric and a slightly larger, submetacentric chromosome with the NOR on its short arms. This chromosome apparently represents the long arm of the original metacentric in which the NOR has been rearranged to the other side of the centromere. Analysis of artificially induced haploid embryos as well as normal diploid embryos from females with 53 chromosomes suggests that meiotic chromosomes undergo alternate disjunction so that only balanced gametes are produced.
Localization of the Hprt locus by in situ hybridization and distribution of loci on the mouse X-chromosome
Authors: Lyon M.F. , Zenthon J. , Burtenshaw M.D. , Evans E.P.
Published: May 2008

The hypoxanthine phosphoribosyltransferase locus (Hprt) of the mouse has been localized by in situ hybridization to band XA6. Comparison of the distributions of known loci on the genetic and cytogenetic maps of the X-chromosome suggests some chiasma localization with a relatively high frequency of chiasmata in the F bands. In the A bands there appear to be fewer known loci than expected, but no evidence has been found so far of excessive chiasma formation.
Chromosomal localization of human endogenous retroviral element ERV1 to 18q22→q23 by in situ hybridization
Authors: Renan M.J. , Reeves B.R.
Published: May 2008

From a clone containing the entire locus of human endogenous retroviral element ERV1, we have obtained a DNA probe that is specific for the 3’ long terminal repeat (LTR) sequence. This probe was used to map the LTR of ERV1 by in situ hybridization to chromosomes from normal human blood lymphocytes. The LTR was found to be localized to the distal portion of the long arm of human chromosome 18, within bands q22→q23. This chromosome locus is near the constitutive fragile site at band q21.3 on chromosome 18 associated with the 14; 18 translocations seen in follicular lymphomas.
A mouse homeo box - containing gene maps near a developmental mutation
Authors: Hill R.E. , Hall A.E. , Sime C.M. , Hastie N.D.
Published: May 2008

Mouse genes containing homeo box domains are predicted to fulfill important functions in embryogenesis. Using recombinant inbred mouse strains, we have mapped a mouse gene which contains a homeo box with homology to the Drosophila engrailed gene. This gene maps to mouse chromosome 1 near or at the dominant hemimelia locus which is a known mouse developmental mutation.
Destabilization of the adenosine deaminase gene sequences in rat-rat somatic cell hybrids
Authors: Hoffee P.A. , Chiang J. , Rowland, III P.
Published: May 2008

Rat hepatoma cells amplified for adenosine deaminase (ADA) gene sequences show the amplified DNA on large, homogeneously staining regions (HSRs). The amplified cells are stable in the absence of selection for 12 mo without loss of ADA activity or gene sequences. However, in hybrids formed between an amplified cell line with a prominent HSR and a nonamplified cell line, rapid loss of ADA activity, as well as gene sequences, occurs. Karyotype analyses of the hybrids indicate that the HSR structures are no longer visible in a large percentage of the hybrid metaphase spreads and appear to have been replaced by DNA structures that resemble double minutes. Our data provide evidence that (1) the extent of the breakdown of the HSR in the hybrids may be affected by the presence of an active adenosine kinase or the level of ATP in the cells and (2) additional unidentified factors are present in the hybrids that affect the integrity of the HSR structure. There is no evidence for a specific transacting factor in nonamplified cells that regulates gene amplification.
Problems in using Robertsonian rearrangements in determining monophyly: examples from the genera Tatera and Gerbillurus
Authors: Qumsiyeh M.B. , Hamilton M.J. , Schlitter D.A.
Published: May 2008

Chromosomal banding data on three species of Tatera from Kenya significantly alter the previous hypothesis of relationships between and within the genera Tatera and Gerbillurus based on cladistic analyses and the rule of parsimony (Qumsiyeh, 1986b). Of the many possible hypothetical relationships, the most parsimonious tree showed three homoplasies and allowed the genus Gerbillurus to be paraphyletic. The alternative trees, depicting larger number of homoplasies but with homoplasies restricted to fusion or fission events, were compatible with the morphological data in supporting the monophyly of Gerbillurus. To choose between the hypothesis based on the most parsimonious chromosomal tree and those supported by both morphology and slightly less parsimonious chromosomal trees, we performed an electrophoretic study on this group of gerbils. The conclusions are that the genus Gerbillurus is monophyletic and represents a branch that is closely related to the T. robusta group of Taterillini. The study documents that fissions and fusions must have occurred frequently and that in some cases the same fusions were acquired in two independent lineages in numbers exceeding those that are predicted by strict parsimony. The results raise questions about the validity of systematic conclusions based solely on fusion/fission data and utilizing the parsimony criterion.
Gene mapping in marsupials and monotremes
Authors: Dawson G.W. , Johnston P.G. , Graves Marshall
Published: May 2008

To study the location of autosomal genes in the wallaroo (Macropus robustus), a number of rodent-kangaroo cell hybrids that retained wallaroo autosomes were typed for 24 enzymes. Expression of the kangaroo form of peptidase A (PEPA), mitochondrial malate dehydrogenase (MDH2), and nucleoside phosphorylase (NP) was detected. Chromosome studies and enzyme analysis of hybrids, subclones, and revertants enabled confident assignment of PEPA to chromosome 4 and tentative assignment of MDH2 to chromosome 1 of this species.
The high-resolution GTG-banding pattern of rabbit chromosomes
Authors: Yerle M. , Echard G. , Gillois M.
Published: May 2008

A cell synchronization technique allowed the high-resolution GTG-banding pattern of rabbit chromosomes to be determined. A karyotype of the late-prophase 622-band stage is presented.
Highly polymorphic DNA sequences in the distal region of the long arm of human chromosome 18
Authors: Müller U. , Donlon T.A. , Harris P. , Rose E. , Hoffman E. , Bruns G.P. , Latt S.A.
Published: May 2008

Highly polymorphic repeated DNA sequences were detected at the end of the long arm of human chromosome 18 by a recombinant DNA probe containing 56 bp of human DNA (pERT25). This was shown by hybridization of pERT25 to DNA from a panel of human × rodent somatic cell hybrids, by dot blot hybridization to flow-sorted human chromosomes, and by in situ hybridization to metaphase chromosomes. The high degree of polymorphism detected by this 18q DNA fragment makes it potentially useful for various applications, including investigations into the genetics of trisomy 18 (Edwards syndrome), linkage studies, and paternity testing.
Exclusion of linkage of loci on chromosome 19 with multiple endocrine neoplasia, type 2
Authors: Carter C. , Easton D.F. , Mathew C.G.P. , Welander G. , Telenius H. , Telenius-Berg M. , Ponder B.A.J.
Published: May 2008

Linkage between seven loci on chromosome 19 and multiple endocrine neoplasia type 2a (MEN2A) was examined in a single large Swedish pedigree. A total of 50 cM was excluded from the male genetic map by pairwise analysis and an estimated 63 cM by multipoint analysis. Using existing data on the likelihood of different marker-marker distances and taking into account current exclusions on other chromosomes, the probability that the gene for MEN2A segregating in this pedigree could still be located on chromosome 19 is approximately 0.28%.
Mammalian sex chromosomes
Authors: Raman R. , Nanda I. , Singh A.P.
Published: May 2008

In the pygmy mouse, Mus dunni, the entire Y chromosome and the short arm of the X and distal region of its long arm are constitutively heterochromatic. Different banding studies on somatic chromosomes revealed the GC nature of the distally located heterochromatin of the long arms of both the X and Y chromosomes. The short arm of the X and the rest of the Y are AT-rich. During meiosis, the long arms of the X and Y paired extensively, sometimes more than half of the Y pairing with the X. This observation is in disagreement with that of Pathak and Hsu (1976) who reported end-to-end pairing between the long arm of the X and the short arm of the Y. The orientation observed by us is favourable to a successful meiotic recombination but whether this takes place remains to be demonstrated.
Under what circumstances is the human XY bivalent tangled? A note on chromosomally-derived sterility
Authors: Rosenmann A. , Wahrman J. , Richler C. , Madgar I. , Weissenberg R. , Chaki R.
Published: May 2008

A microspread, early-mid diplotene nucleus of a man with a normal karyotype and presumably normal meiosis is compared with a similar, earlier described nucleus of a man with meiotic arrest, heterozygous for a (14;21) Robertsonian translocation (Rosenmann et al., 1985). The axes of the XY bivalent of normal diplotene have an extremely tangled configuration, whereas those of the meiotically-arrested cell are straight, recalling the shape of the XY which is normally found in early pachytene. The morphological reversal from the complex configuration to a simpler shape may be associated with reactivation of the sex chromosome(s). Such a reactivation may be responsible for the sterility of the carrier of the Robertsonian translocation which thus may be considered as chromosomally-derived. The diplotene cells shown here have autosomal bivalents with continuous axes and various degrees of focal separation as is typical for diplotene in general. The observations on axis continuity, bivalent segmental dilatations, and XY tanglement in diplotene are compared with findings by others in human ultrathin sectioned material.
HRAS1-selected, chromosome mediated gene transfer; in situ hybridization with combined biotin and tritium label localizes the oncogene and reveals duplications of the human transgenome
Authors: Gosden J.R. , Porteous D.J.
Published: May 2008

Chromosomes isolated from a human bladder carcinoma cell line which contains the actively transforming oncogene HRAS1 on chromosome 11 can be used to transform mouse cells. We have analyzed these chromosome mediated gene transformants by in situ hybridization techniques using biotinylated human DNA and a double antibody detection system to visualize the whole of the transgenome in a number of cell lines. In some transformants, where the amount of the transgenome was below the level of detection by the simple biotin system, we used a gold-silver enhancement technique. We have developed a combined in situ hybridization procedure using biotinylated human DNA plus antibodies and 3H-labeled HRAS1 DNA plus autoradiography to locate the actively transforming oncogene within the human transgenome in a selection of these transformants. In each of these there were complex insertions of the transgenome, either at multiple sites or with duplicated inserts at a single site. Each insertion contained a copy of HRAS1. The double in situ hybridization analysis helps define the types of arrangement and rearrangement which can accompany the chromosome mediated gene transfer process and, consequently, the potentials and limitations of the technique as a somatic cell and molecular genetic tool. Our analysis also suggests that multiple copies of the HRAS1 gene may be needed for stable transformation.
Human platelet factor 4 gene is mapped to 4q12→q21
Authors: Griffin C.A. , Emanuel B.S. , LaRocco P. , Schwartz E. , Poncz M.
Published: May 2008

The gene for human platelet factor 4 has been mapped to the q12→q21 region of chromosome 4 by in situ hybridization. Hybridization of the same probe to leukemic cells carrying a t(4;11)(q21;q23) showed that the human platelet factor 4 gene is proximal to the breakpoint on chromosome 4.
An improved method for preparing G-banded chromosomes from mouse peripheral blood
Authors: Davisson M.T. , Akeson E.C.
Published: May 2008

We describe here several improvements in the method we originally developed to prepare mitotic chromosomes from peripheral blood of laboratory mice. In addition, we have tried several methods to improve metaphase yield from lymphocytes of the inbred strain DBA/2J, which respond poorly to phytohemagglutinin. The yield of mitoses from DBA/2J cells cannot be improved by enhancing T-cell response using interleukin-2 or by using a different T-cell mitogen, concanavalin A. Metaphase yield from peripheral blood cells of DBA/2J mice can be improved significantly by adding lipopolysaccharide to cultures, probably stimulating B-cell as well as T-cell proliferation.
Localization of the multidrug resistance-associated 170 kDa P-glycoprotein gene to mouse chromosome 5 and to homogeneously staining regions in multidrug-resistant mouse cells by in situ hybridization
Authors: Martinsson T. , Levan G.
Published: May 2008

This report describes the localization of the 170 kDa P-glycoprotein gene(s) to mouse chromosome 5, subbands A2 or A3. Overproduction of P-glycoprotein is associated with multidrug resistance (MDR). MDR cell lines derived from the SEWA mouse tumor carry multiple copies of the P-glycoprotein gene. These were found to reside in homogeneously staining regions, situated in different locations in different sublines.
Assignment of the TCP1 locus to the long arm of human chromosome 6 by in situ hybridization
Authors: Fonatsch C. , Gradl G. , Ragoussis J. , Ziegler A.
Published: May 2008

TCPl, the human homolog of the Tcp-1 locus in the mouse, which is part of the murine t complex and codes for an abundant testicular germ-cell protein, has been mapped within the human genome by in situ hybridization. Using a cDNA probe for TCPl, pB1.4hum, we assigned TCPl to human chromosome region 6q23→qter, with the most likely localization being 6q25→q27.
The high resolution R-banded karyotype of Rattus norvegicus
Authors: Rønne M. , Shibasaki Y. , Poulsen B.S. , Andersen O.
Published: May 2008

Representative haploid R-banded karyotypes of the laboratory rat and diagrammatic representation of the banding patterns at the 525-band level are presented.
The chromosomes of Micromys minutus (Rodentia, Murinae)
Authors: Schmid M. , Johannisson R. , Haaf T. , Neitzel H.
Published: May 2008

Both light and electron microscopy were used to study the pairing behavior of the sex chromosomes of the harvest mouse, Micromys minutus, in surface-spread pachytene spermatocytes. The XY pairing pattern is very exceptional in that the site of synaptic initiation is located interstitially in the short arms of the X and the Y, next to their centromeric-regions. From this tiny euchromatic site, synapsis proceeds unidirectionally along the homologous heterochromatic short arms of the X and the Y toward the ends of the chromosomes. After pairing of the short arm is concluded, synapsis begins between the nonhomologous long arms of the X and the Y in the immediate vicinity of the centromeres and progresses unidirectionally toward the end of the long arm of the Y. A synaptic complex develops between the constitutive heterochromatin of the long arm of the Y and the euchromatin of the long arm of the X. Analysis of C-banded and distamycin A/DAPI-stained diakineses revealed a trefoil-like XY bivalent, which was interpreted to be the result of an interstitial chiasma occurring in the paired short arms of the X and the Y. A conspicuous, electron-dense body, about 1 µm in diameter, was found closely associated with the centromeres of the X and the Y in numerous pachytene spermatocytes. A review of the literature showed that comparable XY-associated bodies have been found in only eight other mammals to date.
Delineation of human prometaphase paracentromeric regions using sequential GTG- and C-banding
Authors: Magenis R.E. , Barton S.J.
Published: May 2008

The centromeric-paracentromeric regions of high-resolution human chromosomes have not been examined in detail. It is not clear which bands in the paracentromeric regions are included within the heterochromatin and are therefore not clinically meaningful, and which bands are excluded. This makes breakpoint analysis in these regions difficult. Using sequential G- and C-banding of high-resolution chromosome preparations from four clinically normal subjects and from one patient with a very small interstitial deletion of the chromosome 16 long arm, we have made a detailed analysis of the centromeric-paracentromeric regions of each chromosome and of the entire Y chromosome at the 400, 550, and 800–850 band stages. We present here the results of analysis of preparations at the 800–850 band stage.
Multivariate analysis of karyotypic abnormality in leukemia facilitated by numerical encoding of cytogenetic data
Authors: Peters G.B. , MacCormac L.B.
Published: May 2008

A system is proposed whereby human karyotype data is expressed in quantitative terms rather than in the ISCN (1985) terminology used at present. This recoding facilitates application of multivariate analysis using standard statistical packages. As an example, karyotypes of 714 cases from 11 leukemias (Mitelman, 1983) are here recoded and subjected to discriminant analysis (SPSSx, 1983). Significant karyotypic specificity is apparent in six of the 11 FAB leukemia types. Four others show insignificant levels of specificity, while the last is equivocal. These results merely confirm present views. However, their generation by means of computerized multivariate analysis is novel, and confirms the feasibility of the approach. In this quantitative form, karyotypic data may be combined with any other data of diagnostic or prognostic value. Given such a consolidated data set, desired information concerning any aspect of neoplasia could be extracted via a single procedure.
Localisation on human chromosome 19 of three genes for cell surface antigens defined by monoclonal antibodies
Authors: Brook J.D. , Beresford H.R. , Shaw D.J. , Old L.J. , Rettig W.J.
Published: May 2008

Expression of three distinct human cell surface antigens defined by monoclonal antibodies (mAbs) was examined in a series of rodent-human somatic cell hybrids retaining different subsets of human chromosomes. Cell surface reactivity with mAbs F8 and G253, detecting a 95 kilodalton (kD) glycoprotein (gp95); with mAbs F10 and A103, detecting a 50 kD glycoprotein (gp50); and with mAb S7 was found to cosegregate with human chromosome 19. However, differential antigen expression was observed with hybrids containing fragments of the 19 and hybrids constructed with different human cell types. Comparison of results from the serological typing with the presence of a number of chromosome 19 DNA markers in hybrid cells and cytogenetic analysis suggests that MSK20, the gene coding for the F10/A103 antigen gp50, is located in chromosome region 19pter→19p13.2. The genes coding for the F8/G253 antigen, gp95 (gene symbol MSK19) and the S7 antigen (MSK37) are located in region 19p13.2→19q13.2. Thus, the cell surface antigens described in this study may be used as selectable markers for specific portions of human chromosome 19.
Premature chromosome condensation induced by electrofusion
Authors: Cervenka J. , Camargo M.
Published: May 2008

Premature chromosome condensation of G1 G2, and S-phase chromosomes has been achieved by the use of electrofusion in the fusion of Chinese hamster ovary (CHO) cells and HeLa cells and CHO cells with human leukocytes. Very high yields of heterokaryons, of over 80%, as well as elimination of adverse effects of chemical and viral fusion agents, facilitated induction of premature chromosome condensation of high quality.
The rat MIS1/Pvt-1 locus is syntenic with MYC on chromosome 7
Authors: Ingvarsson S. , Wirschubsky Z. , Szpirer J. , Levan G. , Klein G. , Sümegi J.
Published: May 2008

Mouse Pvt-1 and rat MISl are frequent proviral integration sites in retrovirally induced lymphomas. The Pvt-1 locus is also involved in mouse plasmacytoma (6;15) and in the variant Burkitt lymphoma (2;8) translocations. We show that the Pvt-1/MISl locus is syntenic with MYC on rat chromosome 7. This is consistent with a postulate of close linkage and, possibly, a functional relationship between the MYC protoon-cogene and the MIS1/Pvt-1 locus.
Comparative cytogenetics of Chinese and Japanese raccoon dogs, Nyctereutes procyonoides
Authors: Ward O.G. , Wurster-Hill D.H. , Ratty F.J. , Song Y.
Published: May 2008

We investigated the relationships between subspecies of Nyctereutes procyonoides from China (2n = 54 + B chromosomes) and Japan (2n = 38 + B chromosomes). The chromosomes of Chinese and Japanese raccoon dogs were compared by means of conventional staining, G- and C-banding, and silver nitrate staining of NORs. Extensive G-banding homologies revealed karyotype evolution through chromosomal fusion. We believe the reduced diploid number in the Japanese raccoon dog was achieved by fusion of 16 acrocentrics to form eight metacentric and submetacentric elements. Ten pairs of autosomes appeared to be identical in these subspecies and were presumed to have occurred as such in a common ancestor. G-band patterns of the sex chromosomes were similar in the two subspecies, but differences were noted with other banding and staining techniques. B chromosomes were present in varying numbers and sizes in all animals examined, but the morphology of the B chromosomes differed in the two subspecies. It was concluded from chromosomal and paleontological evidence that the two subspecies were derived from a common mainland ancestor and that the Japanese raccoon dog is a relatively recent form.
Segregation after mitotic crossing-over in isodicentric X chromosomes
Authors: Sarto G.E. , Kuhn E.M. , Therman E.
Published: May 2008

Segregation after mitotic crossing-over in an isodicentric (idic) X chromosome with one active and one inactive centromere has given rise to two new cell lines, one in which the idic(Xpter) chromosome has two active centromeres (most of these chromosomes also have an inversion) and another in which neither centromere is active. The two X chromosomes are attached at the telomeres of their short arms. Similar segregation has given rise to two other cell lines with idic(Xq-) chromosomes. Other observations on segregation after mitotic crossing-over are reviewed. Unequal crossing-over has apparently played a major role in the evolution of various genes and heterochromatin. Retinoblastoma and Wilms tumor are in some cases associated with homozygosity of a chromosome segment resulting from mitotic crossing-over. Similarly, the high incidence of cancer in Bloom syndrome may be caused by mitotic crossing-over leading to homozygosity or amplification of oncogenes.
Cytogenetic analyses of a Salvelinus hybrid reveal an evolutionary relationship between the parental species
Authors: Disney J.E. , Wright, Jr. J.E.
Published: May 2008

Mitotic analyses of the brook trout (Salvelinus fontinalis) × arctic char (S. alpinus) hybrids (sparctic trout) revealed a mode of 2n = 82 with 18 metacentric and 64 acrocentric chromosomes. The brook trout had 2n = 84 with 16 metacentric chromosomes and the arctic char had 2n = 80 with 20 metacentric chromosomes; both species are derivatives of a single tetraploid event. Variable multivalent-like configurations that may be centromeric associations of bivalents were observed in C-banded pachytene figures of female sparctic trout. Metaphase I analyses of sparctic trout males indicated that two fusions of nonhomologous acrocentric chromosomes representing two duplicated chromosome sets must have occurred in the arctic char after its evolutionary divergence from the brook trout. A mode of seven tetravalent rods per cell suggests that preferential multivalent pairing occurs in the sparctic hybrid; metaphase I analyses of S. alpinus males revealed a mode of only five tetravalent rods per cell. The presence of multivalents implies that the arctic char, like the brook trout, is still undergoing diploidization. Cytochemical detection of the nucleolar organizer region (NOR) revealed intra- and interspecific as well as intraindividual variability in the numbers and types of chromosomes (metacentric or acrocentric) on which NORs appeared in arctic char and sparctic trout. Brook trout only had NORs on acrocentric chromosomes. This may indicate that different chromosomal fusions occurred in the evolution of brook trout from arctic char.
A comparative chromosome banding analysis of the Ursidae and their relationship to other carnivores
Authors: Nash W.G. , O’Brien S.J.
Published: May 2008

Trypsin G-banded karyotypes of eight species of Ursidae were prepared from retrovirus-transformed skin fibroblast cultures. The banding patterns of all bears are highly conserved, even though their diploid numbers range from 42 to 72. A comprehensive analysis of the homologous banding patterns within the Ursidae and with a hypothesized ancestral carnivore karyotype permitted the reconstruction of three significant chromosomal reorganization events that occurred during the evolution of the modern ursids. The first was a multichromosomal fissioning away from the biarmed (2n = 44) primitive carnivore karyotype, leading to six species of the Ursinae subfamily (2n = 78). The second was a comprehensive chromosome fusion in the lineage that led to the Ailuropodinae (giant panda) subfamily (2n = 44). The third event was a second, independent, but less extensive, centromeric fusion occurring in the line that led to the Tremarctinae (spectacled bear) subfamily (2n = 52). Ursidae karyotypes are not only highly conserved within the family but also exhibit extensive chromosome banding homology with other carnivore families.
An extended chicken karyotype, including the NOR chromosome
Authors: Auer H. , Mayr B. , Lambrou M. , Schleger W.
Published: May 2008

Chicken chromosomes were identified up to No. 18 by a sequential counterstain-enhanced fluorescence technique. A heterochromatin characterization of macro- and microchromosomes was performed; in general, the microchromosomes were GC-rich, but with a high degree of variation. The NORs are localized on chromosome No. 17.
Detection of Neovessels in Atherosclerotic Plaques of Rabbits Using Dynamic Contrast Enhanced MRI and 18F-FDG PET
Authors: Calcagno Claudia , Cornily Jean-Christophe , Hyafil Fabien , Rudd James H.F. , Briley-Saebo Karen C. , Mani Venkatesh , Goldschlager Gregg , Machac Josef , Fuster Valentin , Fayad Zahi A.
Published: May 2008

Objective—

The association of inflammatory cells and neovessels in atherosclerosis is considered a histological hallmark of high-risk active lesions. Therefore, the development and validation of noninvasive imaging techniques that allow for the detection of inflammation and neoangiogenesis in atherosclerosis would be of major clinical interest. Our aim was to test 2 techniques, black blood dynamic contrast enhanced MRI (DCE-MRI) and 18-fluorine-fluorodeoxyglucose (18F-FDG) PET, to quantify inflammation expressed as plaque neovessels content in a rabbit model of atherosclerosis.

Methods and Results—

Atherosclerotic plaques were induced in the aorta of 10 rabbits by a combination of 2 endothelial abrasions and 4 months hyperlipidemic diet. Six rabbits underwent MRI during the injection of Gd-DTPA, whereas 4 rabbits were imaged after injection of 18F-FDG with PET. We found a positive correlation between neovessels count in atherosclerotic plaques and (1) Gd-DTPA uptake parameters evaluated by DCE-MRI (
r
=0.89,
P
=0.016) and (2) 18F-FDG uptake evaluated by PET (
r
=0.5,
P
=0.103 after clustered robust, Huber-White, standard errors analysis).

Conclusion—

DCE-MRI and 18F-FDG PET may allow for the evaluation of inflammation in atherosclerotic plaques of rabbits. These noninvasive imaging modalities could be proposed as clinical tools in the evaluation of lesion prognosis and monitoring of anti–angiogenic therapies.
Intracellular Localization of Cthrc1 Characterizes Differentiated Smooth Muscle
Authors: LeClair Renée J. , Wang Qiaozeng , Benson Meredith A. , Prudovsky Igor , Lindner Volkhard
Published: May 2008

Objective—

We recently reported expression of collagen triple helix repeat containing-1 (Cthrc1) in injured arteries and proteolytic cleavage of Cthrc1 in smooth muscle cells in vitro. The present study characterizes Cthrc1 processing and determines its biological significance.

Methods and Results—

Domain-specific antibodies localized full-length Cthrc1 in the cytoplasm of vascular, gastrointestinal, and uterine smooth muscle as well as in some neurons. Unlike smooth muscle α-actin, Cthrc1 was not expressed in the embryonic myocardium. Intracellular localization of full-length Cthrc1 was sharply reduced in dedifferentiated smooth muscle of the developing neointima despite the previously shown increase in mRNA levels with accompanying extracellular Cthrc1 immunoreactivity. Immunoblotting suggested an apparent covalent association of monomeric full-length Cthrc1 with a cytoplasmic protein present in differentiated smooth muscle. Plasmin was identified as a protease that cleaved a putative propeptide generating an N-terminally truncated form of Cthrc1 with increased inhibitory activity of procollagen synthesis.

Conclusions—

Our data show that the differentiated smooth muscle cell phenotype is associated with the intracellular localization of noncleaved Cthrc1 despite the presence of a signal peptide. On arterial injury, increased Cthrc1 expression with apparent extracellular localization of N-terminally truncated Cthrc1 occurs. Removal of the propeptide correlated with increased activity of the molecule.
Aldosterone and Angiotensin II Synergistically Stimulate Migration in Vascular Smooth Muscle Cells Through c-Src-Regulated Redox-Sensitive RhoA Pathways
Authors: Montezano A.C. , Callera G.E. , Yogi A. , He Y. , Tostes R.C. , He G. , Schiffrin E.L. , Touyz R.M.
Published: May 2008

Objective—

Synergistic interactions between aldosterone (Aldo) and angiotensin II (Ang II) have been implicated in vascular inflammation, fibrosis, and remodeling. Molecular mechanisms underlying this are unclear. We tested the hypothesis that c-Src activation, through receptor tyrosine kinase transactivation, is critically involved in synergistic interactions between Aldo and Ang II and that it is upstream of promigratory signaling pathways in vascular smooth muscle cells (VSMCs).

Methods and Results—

VSMCs from WKY rats were studied. At low concentrations (10
−10
mol/L) Aldo and Ang II alone did not influence c-Src activation, whereas in combination they rapidly increased phosphorylation (
P
<0.01), an effect blocked by eplerenone (Aldo receptor antagonist) and irbesartan (AT1R blocker). This synergism was attenuated by AG1478 and AG1296 (inhibitors of EGFR and PDGFR, respectively), but not by AG1024 (IGFR inhibitor). Aldo and Ang II costimulation induced c-Src-dependent activation of NAD(P)H oxidase and c-Src-independent activation of ERK1/2 (
P
<0.05), without effect on ERK5, p38MAPK, or JNK. Aldo/Ang II synergistically activated RhoA/Rho kinase and VSMC migration, effects blocked by PP2, apocynin, and fasudil, inhibitors of c-Src, NADPH oxidase, and Rho kinase, respectively.

Conclusions—

Aldo/Ang II synergistically activate c-Src, an immediate signaling response, through EGFR and PDGFR, but not IGFR transactivation. This is associated with activation of redox-regulated RhoA/Rho kinase, which controls VSMC migration. Although Aldo and Ang II interact to stimulate ERK1/2, such effects are c-Src-independent. These findings indicate differential signaling in Aldo-Ang II crosstalk and highlight the importance of c-Src in redox-sensitive RhoA, but not ERK1/2 signaling. Blockade of Aldo/Ang II may be therapeutically useful in vascular remodeling associated with abnormal VSMC migration.
Defective Mer Receptor Tyrosine Kinase Signaling in Bone Marrow Cells Promotes Apoptotic Cell Accumulation and Accelerates Atherosclerosis
Authors: Ait-Oufella Hafid , Pouresmail Vahid , Simon Tabassome , Blanc-Brude Olivier , Kinugawa Kiyoka , Merval Régine , Offenstadt Georges , Lesèche Guy , Cohen Philip L. , Tedgui Alain , Mallat Ziad
Published: May 2008

Objective—

To study the role of Mer receptor tyrosine kinase (mertk) in atherosclerosis.

Methods and Results—

We irradiated and reconstituted atherosclerosis-susceptible C57Bl/6 low-density lipoprotein receptor-deficient female mice (
ldlr
−/−
) with either a mertk
+/+
or mertk
−/−
(tyrosine kinase-defective mertk) bone marrow. The mice were put on high-fat diet for either 8 or 15 weeks. Mertk deficiency led to increased accumulation of apoptotic cells within the lesions, promoted a proinflammatory immune response, and accelerated lesion development.

Conclusions—

Mertk expression by bone marrow-derived cells is required for the disposal of apoptotic cells and controls lesion development and inflammation.
Effects of MEK5/ERK5 Association on Small Ubiquitin-Related Modification of ERK5: Implications for Diabetic Ventricular Dysfunction After Myocardial Infarction
Authors: Shishido Tetsuro , Woo Chang-Hoon , Ding Bo , McClain Carolyn , Molina Carlos A. , Yan Chen , Yang Jay , Abe Jun-ichi
Published: May 2008

Diabetes mellitus (DM) contributes to the exacerbation of left ventricle (LV) dysfunction after myocardial infarction (MI). Activation of ERK5, an atypical mitogen activated protein kinase with transcriptional activity, inhibits apoptosis and LV dysfunction after doxorubicin treatment. SUMOylation has been proposed as a negative regulator of various transcription factors. In the current study, we investigated the role of ERK5-SUMOylation in ERK5 transcriptional activity as well as on DM-mediated exacerbation of LV dysfunction and apoptosis after MI. ERK5 wild-type transcriptional activity was inhibited by Ubc9 (SUMO E2 conjugase) or PIAS1 (E3 ligase), but not in the ERK5-SUMOylation-site defective mutant (K6R/K22R). H
2
O
2
and high glucose, 2 well-known mediators of diabetes, induced ERK5-SUMOylation, and the K6R/K22R mutant, dominant negative form of Ubc9, and siRNA-PIAS1 reversed H
2
O
2
-mediated reduction of ERK5 transcriptional activity in cardiomyocytes, indicating the presence of SUMOylation-dependent ERK5 transcriptional repression. Constitutively active form of MEK5α (CA-MEK5α) inhibited ERK5-SUMOylation independent of kinase activity, but dependent on MEK5-ERK5 association. To investigate the pathological role of ERK5-SUMOylation in DM mice after MI, we used cardiac specific CA-MEK5α transgenic mice (CA-MEK5α-Tg). MI was induced in streptozotocin (STZ)-injected (DM+MI group) or vehicle-injected mice (MI group) by ligating the left coronary artery. The ERK5-SUMOylation was increased in the DM+MI, but not in the MI group. ERK5-SUMOylation, the exacerbation of LV dysfunction, and the number of TUNEL-positive cells in DM+MI was significantly inhibited in CA-MEK5α-Tg mice. Of note, we could not detect any difference of cardiac function after MI in non-diabetic CA-MEK5α-Tg and non-transgenic littermate control mice. These results demonstrated that ERK5 transcriptional activity is subject to downregulation by diabetes-dependent SUMOylation, which resulted in a proapoptotic condition contributing to poor post-MI LV function.
H-Ras Regulates Angiogenesis and Vascular Permeability by Activation of Distinct Downstream Effectors
Authors: Serban Doinita , Leng Jie , Cheresh David
Published: May 2008

Angiogenesis and vascular permeability occur following endothelium activation by vascular endothelial growth factor (VEGF). Downstream mechanisms that define these vascular responses remain unknown. H-Ras activation has been associated with the angiogenic response. However, active H-Ras initiates a wide spectrum of other biological responses through multiple downstream effectors. To identify vascular signaling by H-Ras and the immediate effectors we activated the extracellular signal regulated kinase/mitogen-activated protein kinase or phosphatidylinositol 3-kinase (PI3K) pathways in chicken and mouse endothelial tissues by ectopic expression of the Ras effector mutants H-RasV12S35 or H-RasV12C40, respectively. Constitutive activation of the extracellular signal-regulate kinase/mitogen-activated protein kinase pathway by H-RasV12S35 was sufficient to induce angiogenesis and not vascular permeability, whereas activation of the PI3K pathway by H-RasV12C40 was required for both angiogenesis and vascular permeability. Pharmacological inhibition of PI3K (α/β) suppressed both Ras- or VEGF-mediated vascular response in vivo and survival of primary human endothelial cells in vitro. However, inhibition of PI3K (γ/δ) suppressed Ras- or VEGF-mediated vascular permeability in vivo, with no effect on survival of primary endothelial cells. This was supported by genetic studies because PI3K p110γ knockout mice showed impaired vascular permeability response to VEGF or H-RasV12C40 treatment yet produced a wild-type angiogenic response to H-RasV12S35. We conclude that downstream of VEGF, H-Ras serves as a cellular switch that controls neovascularization and vascular permeability by activation of distinct effectors.