bluuebunny/crossref_metadata_2025 huggingface dataset:
Amplification of the human putative oncogene INT1 in primary retinoblastoma tumors
Authors: Arheden K. , Tommerup N. , Mandahl N. , Heim S. , Winther J. , Jensen O.A. , Prause J.U. , Mitelman F.
Published: May 2008

We report the amplification of the putative oncogene INTl in two of four retinoblastomas. In one case, the INTl signal was amplified 10 to 15-fold, in the other 100-fold. In both cases there were signs of increased tumor aggressiveness with invasion of the choroid and development of metastases. The two cases without INTl amplification had neither metastases nor locally invasive growth. Our findings indicate that INTl amplification may be a feature of increased malignant potential in retinoblastomas.
High frequency of translocation heterozygotes in odd year populations of pink salmon (Oncorhynchus gorbuscha)
Authors: Phillips R.B. , Kapuscinski A.R.
Published: May 2008

The pink salmon (Oncorhynchus gorbuscha) has a rigid two year life cycle so that populations spawning on the even years do not hybridize with populations spawning on the odd years. Examination of the chromosomes of two populations from an even year (1986) and four populations from an odd year (1987) showed that all individuals from the even year populations had a diploid number’of 52, considered the normal number for the species, while a high frequency of individuals in each of the odd year populations sampled from Washington State to Alaska were translocation heterozygotes with a diploid chromosome number of 53. The chromosome involved in the translocation was the seventh metacentric pair containing the NOR (nucleolus organizer region) adjacent to the centromere. In two populations a simple fission of this chromosome has produced individuals with chromosomes with two acrocentrics replacing the metacentric chromosome, with the larger acrocentric having the NOR adjacent to the centromere on the long arm. In the other two populations individuals with 53 and 54 chromosomes were found in which the acrocentric with the NOR has undergone an inversion so that the NOR is now on the short arm of a small submetacentric chromosome. In one population all of the individuals with 53 and chromosomes were of this type, while in the other case both forms were found. Because these two populations are adjacent to each other in the middle of the range sampled, the rearranged chromosome probably had a single origin.
Selective digestion of mouse chromosomes with restriction endonucleases
Authors: Gosálvez J. , Goyanes V.
Published: May 2008

Mouse chromosomes from the L929 cell line have been digested with the restriction endonuclease Haelll and analyzed by electron microscopy. Results show a different effect of the enzyme depending on the conditions of the digestion. Thus, while chromosomes digested in suspended cells show a double scaffold-like structure per chromatid, a similar banding to that found in chromosomes treated for light microscopy is obtained when chromosomes are digested on grids. Some aspects concerning the capacity of the cleaved DNA to be removed from the chromatin are discussed.
Localization of the KRAS2 oncogene in the domestic rabbit (Oryctolagus cuniculus)
Authors: Martin-DeLeon P.A. , Picciano S.R.
Published: May 2008

The KRAS2 gene was localized in the rabbit by chromosomal in situ hybridization, using a 3H-labeled human cDNA probe. There were 201 silver grains on 144 metaphase spreads; 12.9% of the grains resided on chromosome 16, and 54% of these grains were located close to the centromere at 16p11→q11. Statistical analysis indicated that labeling at this region represents a significant deviation from a random distribution and thus provided evidence for the assignment of KRAS2 to 16p11→q11. In addition to the predominant labeling site on 16, there was a positive signal at the telomere of 9q, possibly representing a sequence of another member of the ras family. Our assignment of KRAS2 to rabbit chromosome 16 strengthens the argument that a fragment on this chromosome is homoeologous to one on human chromosome 12, which bears the KRAS2 locus.
Human prostate-specific antigen (APS) is a member of the glandular kallikrein gene family at 19q13
Authors: Sutherland G.R. , Baker E. , Hyland V.J. , Callen D.F. , Close J.A. , Tregear G.W. , Evans B.A. , Richards R.I.
Published: May 2008

The amino acid sequence of human prostate-specific antigen (APS) suggests that it is a member of the glandular kallikrein subfamily of serine proteases. In the mouse, the kallikrein-like family is localized in a single locus on chromosome 7, while other serine proteases are distributed over a variety of different chromosomes. To investigate the physical relationship between the human kallikrein genes, we have used in situ hybridization and Southern analysis of a human × mouse somatic cell hybrid panel to map the APS gene to 19q13, concordant with the renal kallikrein KLK 1 gene. This finding indicates that APS is a member of a human kallikrein-like gene family with analogous organization to that of the mouse.
Chromosomal localization of satellite DNA sequences among 22 species of felids and canids (Carnivora)
Authors: Modi W.S. , Fanning T.G. , Wayne R.K. , O’Brien S.J.
Published: May 2008

In situ hybridization was carried out using cloned satellite DNAs from the domestic cat and domestic dog as probes to metaphase chromosomes from 12 species of felids and 10 species of canids. Autoradiographic silver grains along metaphase chromosomes were counted and analyzed with regard to the mean number of grains per cell in each species, their chromosomal location, and their presence or absence on specific autosomes or sex chromosomes, where known. Among the felids and canids there was a 7.6- and 8.9-fold statistically significant difference, respectively, in the mean number of grains per cell between the species having the minimum and maximum values. Among the felids, most grains occurred on the telomeres of D- and E-group chromosomes, although departures from this general pattern also occurred. For example, the Asian golden cat and the Bornean bay cat showed substantial labeling at the centromeric region of chromosome Al, and a number of species showed some labeling at the short-arm telomeres of B-group chromosomes. Among the canids, about 90% of all grains were located at autosomal centromeres, and grains were absent from the sex chromosomes. Grains are usually distributed at chromosomal locations that stain C-band positive; however, certain C-band-positive regions without grains probably do not contain the particular satellites studied here.
Evolution of heterochromatin-associated satellite DNA loci in felids and canids (Carnivora)
Authors: Fanning T.G. , Modi W.S. , Wayne R.K. , O’Brien S.J.
Published: May 2008

Cloned satellite DNAs that hybridize primarily to C-band-positive regions of felid and canid chromosomes were used to probe the organization of satellite families in the genomes of 16 species of felids and 15 species of canids. Southern-blot and quantitative dot-blot experiments demonstrated that satellite families within the great cats (panthera lineage) vary considerably in regard to amount and/or sequence mismatch and vary some what in regard to restriction patterns. Satellite families within the canids appeared to be more uniform in regard to both amount/ sequence and restriction patterns, although some canid species did differ significantly from the consensus in both respects. Even though intrafamilial satellite restriction patterns were generally similar, every species could be shown to have a unique, characteristic pattern.
Karyotype evolution in the bone marrow of a patient with Fanconi anemia: breakpoints in clonal anomalies of this disease
Authors: Huret J.L. , Tanzer J. , Guilhot F. , Frocrain-Herchkovitch C. , Savage J.R.K.
Published: May 2008

A 21-year-old Fanconi anemia patient developed refractory anemia. Laboratory studies revealed a transitory increased platelet count and a typical del(5q). Bone marrow karyo-typing showed a -6, + der(6)t(1;6)(q12;p25) rearrangement and, two years later, a mosaic-6,-1-der(6), t(1:6)(q12;p25)/-2, +der 2), t(l;2)(q12;q37) constitution. The chromosome mechanism operating in this patient is discussed.
Nondisjunction reduplication of chromosome 3 is not a common mechanism in the development of human renal cell tumors
Authors: Kovacs G. , Wilkens L. , Papp T.
Published: May 2008

Because of the recurrent loss of regions of the chromosome 3 short arm in renal cell carcinomas, a chromosomal mechanism for the expression of recessive cancer genes has been implicated in the development of this type of tumor. Nondisjunction and subsequent reduplication of a mutant chromosome is one of the presumed mitotic mechanisms leading to the expression of recessive cancer genes. Using variant fluorescence at the centromeric region of chromosome 3 and a restriction fragment length polymorphism on chromosome 3p, we found chromosome 3 heteromorphism in the constitutional cells of 14 of 15 patients with renal tumors showing two normal chromosomes 3. This heteromorphism was maintained in each tumor. Therefore, the mechanism of nondisjunction and reduplication in the development of homozygosity for a mutant chromosome 3 in renal tumors remains questionable.
Genetic complementation analysis of ataxia telangiectasia and Nijmegen breakage syndrome: a survey of 50 patients
Authors: Jaspers N.G.J. , Gatti R.A. , Baan C. , Linssen P.C.M.L. , Bootsma D.
Published: May 2008

Cultured cells from patients with ataxia telangiectasia (AT) or Nijmegen breakage syndrome (NBS) are hypersensitive to ionizing radiation. After radiation exposure, the rate of DN A replication is inhibited to a lesser extent than in normal cells, whereas the frequency of chromosomal aberrations is enhanced. Both of these features have been used in genetic complementation studies on a limited series of patients. Here we report the results of extended complementation studies on fibroblast strains from 50 patients from widely different origins, using the radioresistant DNA replication characteristic as a marker. Six different genetic complementation groups were identified. Four of these, called AB, C, D, and E (of which AB is the largest), represent patients with clinical signs of AT. Patients having NBS fall into two groups, VI and V2. An individual with clinical symptoms of both AT and NBS was found in group V2, indicating that the two disorders are closely related. In AT, any group-specific patterns with respect to clinical characteristics or ethnic origin were not apparent. In addition to the radiosensitive ATs, a separate category of patients exists, characterized by a relatively mild clinical course and weak radiosensitivity. It is concluded that a defect in one of at least six different genes may underlie inherited radiosensitivity in humans. To facilitate research on defined defects, a complete list of genetically characterized fibroblast strains is presented.
Molecular analysis of chromosome 1 abnormalities in neuroblastoma
Authors: Ritke M.K. , Shah R. , Valentine M. , Douglass E.C. , Tereba A.
Published: May 2008

Tumor cells from 70% of neuroblastoma patients contain a deletion of part of the short arm of chromosome 1, indicating that this chromosomal region includes a gene involved in tumor formation. To more precisely evaluate the boundaries and mechanisms involved in generating these deletions, we have examined four neuroblastoma cell lines using a combination of somatic cell hybridization, isozyme analysis, and nucleic acid hybridization employing both standard and restriction fragment length polymorphic probes. The data suggest that the truncation of chromosome 1 in these neuroblastomas was most likely due to a complex translocation and deletion mechanism rather than a simple unbalanced translocation or terminal or interstitial deletion. This conclusion is supported by the frequent removal of MYCL from the altered chromosome 1 to another chromosome. Furthermore, the data suggest that the frequency of breakpoints previously assigned by karyotypic analysis to bands other than lp32 in neuroblastomas may be overestimated. Finally, this study identified a breakpoint at 1p32 that was localized between the genes JUN and MYCL for one neuroblastoma thus establishing the order of these genes as centromere, JUN, MYCL, telomere. We conclude that the observed breakpoints within chromosome 1p in human neuroblastoma are not as variable as previously described and suggest the results of this study provide evidence for the involvement of specific DNA sequences within lp32 in the generation of neuroblastoma.
The sex-chromosome constitution and early postimplantation development of diandric triploid mouse embryos
Authors: Kaufman M.H. , Speirs S. , Lee K.K.H.
Published: May 2008

Diandric triploid mouse embryos were produced by standard micromanipulatory techniques, using eggs isolated from female mice with a normal chromosome constitution that had been mated to homozygous Rb(1.3)lBnr males (which carry a large metacentric “marker” chromosome, viz., a Robertsonian translocation involving chromosomes 1 and 3). The tripronucleate embryos were transferred to the oviducts of pseudopregnant mice, which were subsequently autopsied at about midday on the 10th day of gestation. Although a relatively small number of the isolated conceptuses consisted of morphologically abnormal egg-cylinder-like structures or empty gestational sacs, most were at clearly distinguishable embryonic stages, from the primitive streak stage to embryos with about 20 pairs of somites present. These embryos all appeared to be morphologically normal but were substantially smaller than normal (diploid) fertilized embryos analyzed at similar stages of development. A total of 63 diandric triploid conceptuses were recovered and analyzed cytogenetically. They were G-banded to determine their sex-chromosome constitution and confirm their diandric triploid status. No obvious difference was observed in the developmental potential of the 58, XXX class of diandric triploids, compared to that of the 58, XXY class. The ratio of 58, XXX to 58, XXY embryos was close to the expected ratio of 1:2, assuming that unfertilized eggs have an equal chance of becoming fertilized by an X- or a Y-bearing spermatozoon and that the additional (i.e., “donor”) male pronucleus also has an equal chance of having either an X or a Y sex chromosome present. However, the development of the 58, XYY class appeared to be restricted, even at the stage of gestation analyzed, in that no embryos with this genetic constitution were observed that had progressed beyond the early somite stage. The present findings are discussed in relation to the cytogenetic findings in human triploid conceptuses, the majority of which are spontaneously aborted during the first half of pregnancy. In man, the 69, XYY class (equivalent to the 58, XYY class in our study) is only rarely encountered, and it has been assumed that these triploid embryos are probably lost at a very early stage of gestation.
Exclusion of Usher syndrome gene from much of chromosome 4
Authors: Smith R.J.H. , Holcomb J.D. , Daiger S.P. , Caskey C.T. , Pelias M.Z. , Alford B.R. , Fontenot D.D. , Hejtmancik J.F.
Published: May 2008

Usher syndrome is an autosomal recessive disease characterized by dual sensory impairments; affected individuals are born with a sensorineural hearing loss and ultimately lose their sight as retinitis pigmentosa develops. Conventional protein markers previously tested in a Louisiana Acadian kindred suggested tentative linkage to vitamin D-binding protein on chromosome 4. DNA linkage studies do not confirm this linkage relationship and exclude much of chromosome 4 as the site of the Usher syndrome gene in these families.
Molecular cytological differentiation of active from inactive X domains in interphase: implications for X chromosome inactivation
Authors: Dyer K.A. , Canfield T.K. , Gartler S.M.
Published: May 2008

A fluorescence in situ hybridization method using a biotinylated DNA probe specific for the centromeric region of the human X chromosome was used to differentiate the genetically active from the inactive X in interphase cells. With this technique, we were able to interpret both the relative position and the degree of condensation of the X chromosomes within the nucleus. We first established the specificity of fluorescence labelling of the hybridized probe by comparing its location and appearance (either dense or diffuse) when associated with a sex chromatin body (SCB) in early passage normal human female fibroblasts. In these cells, where the presence of inactive X chromatin was verified by identification of a 4’,6-diamidino-2-phenyl indole (DAPI)-positive SCB in 85% of the cells examined, the X chromatin fluorescence was always associated with the SCB. The signal was dense in structure in 98% and peripheral in location in 80% of the nuclei. A second type of signal, diffuse in form, was observed in 85% of the nuclei and presumably represents the location of the active X chromosome. It was located peripherally or centrally with equal frequency and was not associated with any identifiable nuclear component. This diffuse signal was the major type associated with human male fibroblasts. In rodent × human hybrid cells containing a human inactive X, the fluorescent signal was associated with an SCB-like structure in only 13% of the nuclei; it was dense in 66% of the nuclei and equally peripheral or central in location. This indicates an alteration in the interphase structure of the human inactive X chromosome in hybrid cells which may explain its known instability with respect to genetic activity in such systems.
Characterization of an X;X translocation by cytological analysis and in situ hybridization
Authors: Raimondi E. , Vagnarelli P. , Bensi M. , De Carli L.
Published: May 2008

An X;X chromosomal translocation was ascertained by conventional cytogenetic analysis in a phenotypically normal woman with secondary amenorrhea. In situ hybridization was performed with previously mapped X-specific DNA sequences to study the rearrangement at the molecular level. The results allowed us to demonstrate that the subject is monosomic for the distal region of the short arm of the X and trisomic for the distal region of the long arm.
An inversion polymorphism of a DA/DAPI-positive chromosome pair in Anas platyrhynchos (Aves)
Authors: Mayr B. , Lambrou M. , Schweizer D. , Kalat M.
Published: May 2008

A specific type of heterochromatin (DA/DAPI-posi tive heterochromatin) was detected in the genome of Anas platyrhynchos f. domestica L. (domestic duck). The DA/DAPI-positive autosome pair was polymorphic with respect to its occurrenceand size and was also involved in an inversion polymorphism
Chromosome mapping of the growth hormone receptor gene in man and mouse
Authors: Barton D.E. , Foellmer B.E. , Wood W.I. , Francke U.
Published: May 2008

Pituitary growth hormone (GH) is essential for normal growth and development in animals and GH deficiency leadsto dwarfism. This hormone acts via specific high-affinity cell surface recepters found in liver and other tissues. The recent cloning and sequencing of cDNAs encoding human and rabbit GH receptors (GHR) has demonstrated that this receptor is unrelated to any previously described cell membrane receptor or growth factor receptor. We have used the cloned human GHR cDNA to map the GHR locus to the proximal short arm of human chromosome 5, region p13.1→p12, and to mouse chromosome 15 by Southern blot analysis and in situ hybridization. While human chromosome 5 carries several genes for hormone and growth factor receptors, GHR is the only growth-related gene so far mapped to the short arm. Inasmuch as GHR is the first gene with apparently homologous loci on human chromosome 5 and mouse chromosome 15, it identifies a new homologous conserved region. In humans, deficiency of GH receptor activity probably causes Laron-type dwarfism, an autosomal recessive disorder prevalent in Oriental Jews. In mice, the autosomal recessive mutation miniature (mn) is characterized by severe growth failure and early death and has been mapped to chromosome 15. Our assignment of Ghr to mouse chromosome 15 suggests this as a candidate gene for the mn mutation.
The gene for human carbonic anhydrase VI (CA6) is on the tip of the short arm of chromosome 1
Authors: Sutherland G.R. , Baker E. , Fernandez K.E.W. , Callen D.F. , Aldred P. , Coghlan J.P. , Wright R.D. , Fernley R.T.
Published: May 2008

The gene encoding the human secreted carbonic anhydrase isozyme CAVI (CA6) maps to chromosome 1 by Southern analysis of a somatic cell hybrid panel and to 1p36.22→p36.33 by in situ hybridization. CA6 is therefore not linked to the cytoplasmic carbonic anhydrase genes on chromosome 8 or to CA7 on chromosome 16.
High resolution chromosome banding in the Norway rat, Rattus norvegicus
Authors: Satoh H. , Yoshida M.C. , Sasaki M.
Published: May 2008

High resolution banded chromosomes were prepared from a synchronized culture of rat fibroblasts. A maximum of 457 bands per haploid chromosome set were observed. This represents a two-fold increase when compared to the number of bands visualized in mid-metaphases using standard procedures. By reference to both G- and Q-banded karyotypes, we constructed improved idiograms of rat chromosomes at 300- and 400-band stages, respectively.
Regional mapping of the human gene encoding the novel pituitary polypeptide 7B2 to chromosome 15q13→q14 by in situ hybridization
Authors: Roebroek A.J.M. , Dehaen M.R.M. , van Bokhoven A. , Martens G.J.M. , Marÿnen P. , van den Berghe H. , Van de Ven W.J.M.
Published: May 2008

Genetic sequences encoding the novel pituitary polypeptide 7B2 were isolated from a human pituitary cDNA library. Hybridization analysis of a panel of human × mouse cell hybrids with a 7B2 cDNA probe indicated that the locus for the human 7B2 gene is probably located on chromosome 15. In situ hybridization analysis of metaphase chromosomes allowed the regional localization of the 7B2 gene to chromosome 15 at q13→q14.
Analysis of complex Y chromosome aberrations using a single DNA probe (Y-367)
Authors: Müller U. , Fontaine D. , Adinolfi M. , Fraccaro M. , Lalande M.
Published: May 2008

A specific cloned DNA sequence (Y-367) detects at least four loci in the euchromatic long arm and in the short arm of the human Y chromosome. Deletion mapping assigns one locus to the distal euchromatic long arm, another to a region close to the centromere on either Yq or Yp, and two additional loci to the Y short arm. Y-367 may thus be used for the rapid screening of even complex Y chromosome aberrations. This is exemplified in a 45, X male with Y chromosome material on the long arm of chromosome 10 by the detection of an inversion of a portion of Yp and by the confirmation of duplications and deletions in two individuals with duplications of part of the Y chromosome.
Localization of human adenosine deaminase (ADA) gene sequences to the q12→q13.11 region of chromosome 20 by in situ hybridization
Authors: Jhanwar S.C. , Berkvens T.M. , Breukel C. , van Ormondt H. , Van der Eb A.J. , Meera Khan P.
Published: May 2008

The gene for human adenosine deaminase (ADA), an enzyme constitutively expressed in all tissues investigated so far and deficient in some cases of severe combined immune deficiency, was previously assigned to chromosome 20 by syntenic analysis, using somatic cell hybrids and quantitative enzyme studies on patients with chromosome abnormalities. Attempts at regional localization of ADA through indirect approaches have so far resulted in uncertainties, as well as apparent inconsistencies. In situ hybridization of high-resolution somatic and pachytene chromosomes using al 3H-abeled cDNA probe of the ADA gene localized the gene to 20q12→q13.11. Rearrangements involving this region have been reported in various human hematological malignancies; in this regard, possible implications of the physical proximity of the ADA gene locus to that of SRC, an oncogene previously localized to the same region of chromosome 20, are briefly discussed.
Physical mapping of probes proximal to the fragile X locus (FRAX) confirms the order F9-DXS105 (cX55.7)-DXS98 (4D8)-FRAXA
Authors: Sauer S.M. , Phelan M.C. , Richer C.-L. , Schwartz C.E.
Published: May 2008

A woman with an abnormal karyotype, (46, X, der(X) (pter→q27::q27→q21), was analyzed using DNA probes in the region Xq27→qter. The results indicate that she is trisomic for the Factor IX locus, disomic for the locus DXS105 (cX55.7) and monosomic for the loci DXS98 (4D8), DXS52 (St14) and Factor VIII. This confirms the absence of the region Xq28 in the abnormal chromosome. Furthermore, the presence of only one copy of 4D8 and two copies of cX55.7 places the DXS98 locus distal to Factor IX and closer to the fragile X locus than DXS105.
Heterochromatin variation and spermatogenesis in Nesokia
Authors: Juyal R.C. , Thelma B.K. , Rao S.R.V.
Published: May 2008

A probable role of heterochromatin variation in male meiosis has been evaluated using fertile and infertile Indian mole rat males (Nesokia) with polymorphic X and/or Y chromosomes. A comprehensive study of tubular histology, meiotic progression, and X-Y chromosome pairing was undertaken. Despite heterochromatin variation, spermatogenesis was found to be complete in all individuals. Patterns of X-Y synaptonemal complex pairing varied considerably from extensive synapsis in individuals with a normal heterochromatin complement, through end-to-end synapsis, to X and Y univalents in those with different degrees of loss of heterochromatin. Changes in the gonadal histology corresponding to heterochromatin variation were also observed. Loss of some coding DNA sequences in polymorphic X-chromosomes otherwise located at specific sites in the X-chromosome heterochromatin have been linked directly to modifications of the reproductive process. This is thought to be mediated by an altered X-chromosome activity during spermatogenesis or regulation of other locus/loci involved in fertility or reproduction.
The HLA class I locus: analysis of RFLPs in hereditary hemochromatosis
Authors: Hansen J.L. , Kushner J.P.
Published: May 2008

The gene for hereditary hemochromatosis is linked to the HLA locus on chromosome 6. Four cloned DNA probes originating from the HLA class I region were used to detect seven restriction fragment length polymorphisms (RFLPs). Allele frequencies and segregation of each RFLP was determined. Analysis of RFLPs in 38 unrelated homozygotes with hemochromatosis revealed differences in allele frequencies between the control and the hemochromatotic groups but these differences did not reach statistical significance. Some differences persisted, however, even when only controls with the A3 antigen were compared with A3 hemochromatotics. Since both control and hemochromatotic groups were small, further studies will be necessary to ascertain whether these RFLPs could serve to locate the gene responsible for hereditary hemochromatosis.
Chromosome 7 long-arm deletions in myeloid disorders: terminal DNA sequences are commonly conserved and breakpoints vary
Authors: Kere J. , Donis-Keller H. , Ruutu T. , de la Chapelle A.
Published: May 2008

Deletions in the long arm of chromosome 7 are common recurrent abnormalities in secondary leukemias and myelodysplastic syndromes. To learn more about the basic mechanisms involved, we used Southern blot analysis to study four patients with different 7q — deletions to determine the exact breakpoints and to define the extent of the deletions. Several genes and DNA sequences from 16 different loci were found to be deleted, as judged by the absence or considerable weakening of an allelic band in granulocytic DNA in patients with constitutional heterozygosity. A terminal segment was present in each of the partially deleted chromosomes, as shown by heterozygosity for probes from the region 7q35→qter in granulocyte DNA. This indicated that the chromosome 7q deletions were interstitial, rather than terminal, in each of these patients. The length of the preserved terminal segment varied among the patients. Our results support gene loss as a mechanism contributing to leukemogenesis. Since the deletions are interstitial, hybrid genes may be formed at the junction, but the variation in breakpoints argues against the existence of a common hybrid gene of importance to the malignant process.
Localization of the human gene for the E1α subunit of branched chain keto acid dehydrogenase (BCKDHA) to chromosome 19q13.1→q13.2
Authors: Fekete G. , Plattner R. , Crabb D.W. , Zhang B. , Harris R.A. , Heerema N. , Palmer C.G.
Published: May 2008

The gene encoding the Elα subunit of branched chain keto acid dehydrogenase (BCKDHA) was mapped to human chromosome region 19q13.1→q13.2 using 3H-labeled cDNA hybridized in situ to human chromosomes.
Banding studies and synaptonemal complex analysis of an X-autosome translocation in the domestic pig
Authors: Gustavsson I. , Switoński M. , Iannuzzi L. , Plöen L. , Larsson K.
Published: May 2008

In a litter of nine domestic pigs, a translocation between the X-chromosome and chromosome 13 was found in six individuals: four males and two females. The translocation was presumed to have originated in the dam. Banding studies indicated that the breaks preceding the translocation had occurred in a distal GTG-negative band of the long arm of the X, 15–30% of the length of Xq from thetelomere, and proximally in chromosome 13, 15–25% from the centromere. The normal X of the females invariably replicated its DNA late. Synaptonemal complex analysis of spermatocytes demonstrated a quadrivalent in 75 of 85 analyzable cells (88.2%), and in 10 cells (11.8%) one trivalent and one univalent were found. Extensive nonhomologous pairings were visualized in the pachytene stage by applying an ‘overlap’ test measuring the sex chromosomes and collating their pairings. An arrest in male meiosis was verified histologically; no meiotic stages later than pachytene developed. This resulted in sterility, with considerable testicular hypoplasia. The records of female fertility were available only for the dam and did not show any deviations from the average of the herd.
A somatic cell hybrid mapping panel for regional assignment of human chromosome 13 DNA sequences
Authors: Cowell J.K. , Mitchell C.D.
Published: May 2008

We have constructed somatic cell hybrids containing different overlapping deletions involving human chromosome 13. Cytogenetic characterisation of the breakpoints allowed division of the chromosome into six distinct regions. Molecular characterisation of these hybrids allowed regional assignment of anonymous DNA sequences, cDNAs, and isoenzyme variants and these hybrids should prove valuable in the analysis and isolation of genes and disease loci on chromosome 13.
Precise in situ localization of NCAM, ETS1, and D11S29 on human meiotic chromosomes
Authors: Bello M.J. , Salagnon N. , Rey J.A. , Guichaoua M.R. , Bergé-Lefranc J.L. , Jordan B.R. , Luciani J.M.
Published: May 2008

In order to sublocalize NCAM, ETSl, and the anonymous DN A fragment D11S29 within 11 q23, in situ hybridization was performed on pachytene bivalents. Analysis of the grain distribution within the band 11q23 indicated that the chromosomal sublocalization of both NCAM and D11S29 was in llq23.1, whereas ETSl was found to be localized in 1 lq23.3. These results clearly demonstrate the usefulness of in situ hybridization applied to pachytene bivalents to obtain accurate gene sublocalization.
Post-implantation development and cytogenetic analysis of diandric heterozygous diploid mouse embryos
Authors: Kaufman M.H. , Lee K.K.H. , Speirs S.
Published: May 2008

Diandric heterozygous diploid mouse embryos were produced by standard micromanipulatory techniques using eggs from female mice with a normal chromosome constitution and fertilised by homozygous Rb(1.3)1Bnr males containing a pair of large metacentric marker chromosomes in their karyotype. The constructed diandric eggs were transferred to the oviducts of pseudopregnant recipients and subsequently autopsied midday on the eighth day of gestation. From a total of 85 eggs transferred to females that subsequently became pregnant, 30 implanted. Eighteen implantation sites were found to contain resorptions, and 12 egg cylinder stage embryos were recovered. These were cytogenetically examined. In two cases, no mitoses were observed, and in a third embryo of normal size, only a single paternally-derived marker chromosome was present in its mitoses, indicating that this embryo had a normal chromosome constitution. This presumably resulted from a technical error during the micromanipulatory procedure. The remaining nine morphologically small but normal embryos were diploid, and each had two paternally-derived marker chromosomes, thus establishing their ploidy and confirming their diandric origin. G-banding analysis revealed that all of these embryos had an XY sex chromosome constitution. Since the expected XX : XY : YY ratio of 1 : 2 : 1 was not observed, it is clear that the XX class embryos were lost at some stage during the pre- or early post-implantation period, though whether they are represented by the resorption sites is not yet established. The YY class would not be expected to be recovered in any case, as these embryos are believed to be lost during early cleavage. The cytogenetic findings reported here are therefore similar to the results of the chromosomal analyses of the human complete hydatidiform moles of dispermic origin, all of which apparently have an XY karyotype. It is unclear why, both in the human and in the mouse, the XX diandric heterozygous diploid group should develop poorly compared to similar embryos with an XY karyotype.
X-chromosome inactivation in the human cytotrophoblast
Authors: Harrison K.B.
Published: May 2008

Preferential paternal X-chromosome inactivation occurs in the cell lineages that differentiate first within the female rodent blastula (trophectoderm and extraembryonic endoderm). The present studies were designed to test the nature of X-chromosome inactivation (XCI) in the earliest differentiating cell lineage of the human placenta, the cytotrophoblast. Using glucose-6-phosphate-dehydrogenase (G6PD) polymorphisms as a marker system, term placentae were obtained from 13 female heterozygotes where parental allelic contributions could be determined. Chorionic villi were enzymatically digested and centrifuged in a Percoll density gradient to isolate a pure population of cytotrophoblasts, which was ascertained by cell culture, differentiation to syncytiotrophoblasts. and histochemical staining for α-human chorionic gonadotrophin (α-HCG). On electrophoresis, all 13 samples exhibited exclusive or near exclusive expression of the maternally derived X-linked enzyme variant, regardless of whether it was G6PD A or G6PD B. No intermediate bands were seen, indicating a single active G6PD locus per cell. The stromal cells of the villi, which derive from the mesoderm and differentiate later than the cytotrophoblast, exhibit random XCI. These findings establish preferential paternal XCI in the cytotrophoblast, the cell type first to differentiate within the human blastula.
Regional mapping of the FOS oncogene to rat chromosome 6q21→q23
Authors: Li S.Z. , Oikawa T. , Yoshida M.C. , Naito H. , Kuzumaki N.
Published: May 2008

Using a panel of rat × mouse somatic cell hybrids and in situ hybridization, we determined the chromosomal location of the rat FOS gene locus. Southern blot analysis assigned this oncogene to rat chromosome 6. In situ hybridization confirmed this finding and mapped the gene more precisely to 6q21→q23.
Loss of heterozygosity in human germinal tumors
Authors: Radice P. , Pierotti M.A. , Lacerenza S. , Mondini P. , Radice M.T. , Pilotti S. , Della Porta G.
Published: May 2008

The frequency of losses of heterozygosity has been investigated in 14 germinal tumors of the testis. Nonrandom deletion of whole or part of chromosome 11 was observed in four cases. In addition, loss of heterozygosity of all the informative loci analyzed was detected in one ovarian teratoma, indicating its post-meiotic origin. These results suggest that different genetic mechanisms (chromosomal deletions or meiotic segregation) that unmask putative recessive mutations are involved in the onset of germinal tumors.
Cryogenic preservation of mammalian testicular material for synaptonemal complex analysis
Authors: Sudman P.D.
Published: May 2008

Synaptonemal complex (SC) analyses have been used in mammalian cytogenetics to investigate the effects of chromosome heterozygosity on meiotic processes. To date, these analyses have been limited largely to the study of humans, livestock, or species which are easily maintained in the laboratory. The development of a method for the cryogenic preservation of testicular tissue for SC analyses allows for the application of this approach to field-oriented biological problems. This new method is described and data are presented which demonstrate its utility to mammalian cytogenetic studies.
A somatic cell hybrid panel to facilitate identification of DNA sequences in the vicinity of the incontinentia pigmenti locus (IP1)
Authors: Gorski J.L. , Stein C.K. , Glover T.W.
Published: May 2008

Somatic cell hybrids that retain derivative X chromosomes from women with sporadic incontinentia pigmenti (IP1) and de novo X/autosomal translocations with consistent breakpoints at Xp11.21 were constructed. An assembled hybrid panel was used to physically map DNA sequences in relationship to the 1P breakpoint. DSX14 was found to map to region Xp11.21→p11.1. Regional assignments of 19 X-chromosomal loci were reviewed.
In situ methylation of human chromosomes with methylase-AluI
Authors: Fernández-Piqueras J. , Ludeña P. , Sentís C.
Published: May 2008

A method for in situ DNA methylation with the pro-karyotic methylase Alul has been developed for use on fixed human chromosomes. Incorporation of methyl groups into the chromosomal DNA has been shown by autoradiography using a labeled substrate. The methylation prevents the digestion of chromosomal DNA by Alul, allowing direct visualization of clusters of nonmethylated AGCT targets along the human complement.
Meiosis in trisomic female mice with Robertsonian translocations
Authors: Polani P.E. , Crolla J.A. , Roberts H.J.
Published: May 2008

The prophase oocytes of two murine Robertsonian translocation (Rb) trisomies of chromosomes 16 and 19 were investigated using electron microscopy and a whole-cell micro-spreading technique after silver staining. About 20% of fetuses of each type were trisomic. They were obtained by mating animals heterozygous for two Rb’s, monobrachially homologous for either chromosome 16 or 19, to an entirely acrocentric stock. Because of the almost inevitable prenatal mortality of the trisomic embryos, their fetal ovaries were “rescued” by an in vitro method for prophase studies. Analysis of the recovered oocytes showed frequent, close pairing associations of the three trisomic axes and evidence suggesting that the closely apposed axes coincided with the side-by-side formation of parallel, complete, true synaptonemal complexes; hence, the cytogenetic dogma that pairing is always two-by-two was contradicted. The presence of two parallel complexes has implications for crossing-over recombination. Triple associations of axes were found in almost half the trisomy 19 (Ts19) and in about 70% of the trisomy 16 (Tsl6) prophases. The extent of triple associations varied and was greater in Ts16 than in Ts19 oocytes. Other relevant observations concerned the proportions of univalents and of univalence of the trisomic axes (21% in Tsl6 and 46% in Tsl9) and the distinctive, thickened appearance of all univalent axes. The pairing behaviour observed in balanced heterozygotes confirms what appears to be nonhomologous pairing and synaptic adjustment within the short-arm axes of the Rb trivalents.
Genetic convergence during serial in vitro passage of a polyclonal squamous cell carcinoma
Authors: Heim S. , Caron M. , Jin Y. , Mandahl N. , Mitelman F.
Published: May 2008

A cell line was established from an in situ squamous cell carcinoma of the skin (Bowen’s disease), and its in vitro karyotypic evolution was cytogenetically analyzed. Initially, considerable genetic heterogeneity was evident. Nine cytogenetically abnormal clones, eight of which were apparently unrelated, were found among the 83 metaphases analyzed from the primary culture and the first passage. With increasing time in culture this complexity was reduced, so that a single clone dominated passages 7–11. The clone that emerged from this genetic convergence had a t(12;17) (p13;q21) as the sole abnormality. Our findings indicate that the cytogenetic multiclonality that has been repeatedly detected in short-term cultures of squamous cell carcinomas is not caused by the in vitro conditions. Instead, the principles of Darwinian selection apply: the altered, but stable, selection pressure facing a newly established and initially multiclonal cell line will lead to a reduction of genetic heterogeneity until the one clone that now has the proliferative advantage outgrows the other sub-populations.
Assignment of the gene coding for human peroxisomal 3-oxoacyl-CoA thiolase (ACAA) to chromosome region 3p22→p23
Authors: Bout A. , Hoovers J.M.N. , Bakker E. , Mannens M.M.A.M. , Geurts van Kessel A. , Westerveld A. , Tager J.M. , Benne R.
Published: May 2008

The chromosomal location of the human gene coding for peroxisomal 3-oxoacyl-CoA thiolase (ACAA) was determined with the aid of cDNA and genomic probes by screening of rodent × human somatic cell hybrids and in situ hybridization. The results localize the gene to chromosome region 3p22→p23.
Analysis of the sex-chromosome constitution of digynic triploid mouse embryos
Authors: Speirs S. , Kaufman M.H.
Published: May 2008

LT/Sv strain mice regularly ovulate up to 50% of their eggs as primary oocytes, which are fertilisable and give rise to digynic triploid embryos. A similar number of eggs are ovulated as secondary oocytes and, following fertilisation, give rise to normal diploid embryos. Pregnant LT/Sv females were autopsied at about midday on day 10 of gestation, when normal diploid embryos would be expected to possess between 25 and 30 pairs of somites. While a few of the triploid embryos either consisted of disorganised embryonic masses or were resorbing, most were at readily recognisable embryonic stages. Just over half of the embryos recovered were “unturned,” while the remainder had “turned” and possessed between 15 and 25 pairs of somites. The triploids were usually readily recognised, owing to their small size and because they often displayed neural tube and cardiac defects. All of the embryos recovered were analysed cytogenetically by G-banding to establish their ploidy and sex-chromosome constitution. The XY:XX sex ratio of the 105 diploid embryos recovered, all of which had “turned,” was 1.06:1 while the overall XXY: XXX sex ratio of the 120 triploids was 1:1. Analysis of only the developmentally most advanced triploid embryos (i.e., the 49 that had “turned”) revealed that the XXY: XXX sex ratio in this group was 1.13:1, which was not significantly different from the expected ratio of 1:1. The crown-rump lengths of the XY and XX “turned” embryos were almost identical, as were those of the XXY and XXX “turned” embryos, although the triploids were significantly smaller than the diploids. No obvious effect of sex-chromosome constitution on developmental potential was therefore observed in this study in relation to either the digynic triploid or the control diploid embryos.
Expression of rat hepatocyte plasma membrane antigens in hybrid clones: assignment of genes coding for two antigens of the basolateral domain to chromosomes 11 and 13
Authors: Perrotez C. , Maurice M. , Feldmann G. , Szpirer C. , Szpirer J. , Parent I. , Cassio D. , Levan G.
Published: May 2008

Expression of three rat hepatocyte plasma membrane antigens defined by monoclonal antibodies (mAbs) was examined by immunofluorescence in mouse hepatoma × rat hepatocyte hybrid clones segregating rat chromosomes. The antigen defined by mAb Bl, a marker of the lateral domain of the hepatocyte plasma membrane in vivo, was expressed in hybrids retaining the rat chromosome 11. The antigen defined by mAb A39, mainly located on the sinusoidal (basal) domain of the plasma membrane in vivo, was expressed when chromosome 13 was present. The genes coding for these two antigens were thus assigned to chromosomes 11 and 13, respectively. The antigen defined by mAb B10, exclusively located on the canalicular (apical) domain of the plasma membrane in vivo, was not expressed in most hybrid clones, and the chromosome location of the gene could not be determined.
Localization of the β-like globin gene cluster and the genes for parathyroid hormone and c-Harvey-ras 1 to region q14→q21 of rabbit chromosome 1 by in situ hybridization
Authors: Xu J. , Hardison R.C.
Published: May 2008

The rabbit β-like globin gene cluster (HBBC), comprised of Ε-, γ-, δ-, and β-globin genes (HBE, HBG, HBD, and HBB, respectively), has been mapped to chromosome 1, region q14→q21, by in situ hybridization using probes for rabbit HBE and HBG. Probes for the human parathyroid hormone gene (PTH) and the Harvey-mi 1 protooncogene (HRAS1) also localize to this region by in situ hybridization. Thus, these genes are syntenic in lagomorphs as well as four other mammalian orders (primates, rodents, carnivores, and artiodactyls). The mapping data in rabbits provide further evidence that this synteny is strongly conserved in the evolution of mammalian chromosomes.
Fine localization of genes on distal murine chromosome 15
Authors: Adolph S. , Berchtold M.W. , Hameister H.
Published: May 2008

The following genes were localized by in situ hybridization on distal chromosome 15 of the mouse: thyroglobulin (Tgn) to 15D3/E, parvalbumin (Pva) to 15E, and the NADH-dependent cytosolic form of glycerol-3-phosphate dehydrogenase (Gdc-1) to 15F1–3. These genes belong to three different conserved chromosomal linkage groups on human chromosomes 8, 22, and 12, respectively.
Chromosome breakage induced by bleomycin in an ataxia telangiectasia lymphoblastoid line: correlation with fragile sites and Epstein-Barr virus DNA localization
Authors: Caporossi D. , Tedeschi B. , Vernole P. , Porfirio B. , Nicoletti B.
Published: May 2008

We have analyzed the distribution of bleomycin-induced breaks in a subline of the ATL9 lymphoblastoid line, derived from peripheral lymphocytes of an ataxia telangiectasia patient, transformed in vitro by Epstein-Barr virus (EBV). As reported elsewhere (Caporossi et al., 1988), the major feature of this subline, ATL9/g, is a stable achromatic gap at lp32 in one of the chromosomes 1, overlapping a preferential site of EBV localization. The results of this paper show that this gap is highly sensitive to bleomycin-induced damage. In addition, the breaks induced by bleomycin in ATL9 cells are distributed nonrandomly and are preferentially localized in bands where fragile sites have been mapped.
Assignment of the gene coding for the α1 chain of collagen type XIII (COL13A1) to human chromosome region 10q11→qter
Authors: Pajunen L. , Tamminen M. , Solomon E. , Pihlajaniemi T.
Published: May 2008

The gene coding for the αl chain of human type XIII collagen, COL13A1, is assigned to chromosome region 10q11→qter by Southern blot hybridization of DNA from 24 human × rodent somatic cell hybrids using a cloned cDNA as probe. A number of previous reports indicate that 10 of the collagen genes are located on six autosomes, but no other collagen genes have been found on chromosome 10. The data therefore provide further evidence for the dispersion of members of the collagen gene family throughout the genome.
Assignment of two rat dihydrofolate (DHFR) genes to chromosomes 2 and 4
Authors: Hanson C. , Andersson A. , Islam M.Q. , Szpirer J. , Szpirer C. , Levan G.
Published: May 2008

A panel of rat × mouse cell hybrids was used in the chromosomal mapping of the rat dihydrofolate reductase (DHFR) gene. It was determined that the probe hybridized to gene sequences on two different chromosomes (Nos. 2 and 4), possibly representing the active gene and a pseudogene. Hybridization of the DHFR probe to DNA from a methotrexate resistant rat cell line revealed that the gene on chromosome 2 was amplified, but not the gene on chromosome 4. This result was taken to suggest that the active DHFR gene is located on rat chromosome 2 and that the sequence on chromosome 4 is a pseudogene.