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PubMed1983

[Dicentric Yp chromosome as one of the reasons for the absence of fluorescence in human Y chromosome].

In chromosome sets of three patients with Turner's syndrome non-fluorescent Y-chromosomes of normal size were found in part of the cells. C-, Q- and G-techniques have shown that they were dicentric Yp-chromosomes, resulting from a junction of long arms of two Y-chromosomes with simultaneous loss of the entire distal fluorescent segments. It is supposed that in some cases the non-fluorescent Y-chromosomes, previously described in literature, are as a matter of fact undiscernible dicentric Yp-chromosomes.

Adolescent↗
PubMed1997

Nonrandom chromosome segregation in male meiosis of a sciarid fly: elimination of paternal chromosomes in first division is mediated by non-kinetochore microtubules.

The mechanism of nonrandom chromosome segregation and elimination in male first meiotic division of sciarid flies is one of the enigmas of classical cytogenetics. Interpretations of the available data regarding this unusual chromosome transport are contradictory [reviewed by Gerbi, 1986: "Germline-Soma Differentiations. Results and Problems of Cell Differentiation," Vol. 13:71-104]. In the present study of spermatogenesis in Trichosia pubescens the process is reinvestigated by indirect anti-tubulin immunofluorescence labeling of spindle microtubules and DAPI chromosome staining, partly in combination with ultrathin sectioning and electron microscopy. While the maternal homologues and the sex-limited (L) chromosomes seem to be transported very quickly toward the pole of the monopolar spindle, where they stay throughout first meiotic division, paternal homologues remain some distance from the pole, stick together, and, as an undifferentiated cluster of chromatin, withdraw from the pole in the course of division. Finally the paternal chromatin becomes eliminated in a cytoplasmic bud which is cast off. The different behavior of maternal homologues (and L chromosomes) and paternal homologues may be caused by differences in kinetochore structure and function. In contrast to maternal and L chromosomes, the paternal homologues do not display structurally defined kinetochore-like regions and seem to be unable to orient poleward. During the process of elimination, a prominent bundle of pole-oriented microtubules is associated with the paternal chromatin cluster. It is suggested that transport away from the pole is brought about by these microtubules. Thus, meiotic chromosome elimination in sciarids may be related to mechanisms involving "polar ejection forces" [Rieder et al., 1986: J. Cell Biol. 103:581-591].

Animals↗
PubMed1981

The role of chromosome 15 in murine leukemogenesis. I. Contrasting behavior of the tumor vs. normal parent-derived chromosomes No. 15 in somatic hybrids of varying tumorigenicity.

G-banding analysis was carried out on a series of hybrids derived from the fusion of a chromosome 15-trisomic murine T-cell leukemia of AKR origin and normal diploid fibroblasts or lymphocytes of the CBT6T6 strain. Due to the 14;15 translocation involved in the generation of the T6 marker, the chromosomes No. 15 and 14 derived from the normal and the tumor parent can be distinguished cytogenetically. Highly tumorigenic, in vitro maintained hybrids, and high-tumorigenic segregants of originally low-tumorigenic in vitro hybrids, selected by in vivo passage, showed a similar cytogenetic pattern. It was characterized by the amplification of the tumor-derived chromosomes No. 15 from the expected 3 to 5.5 +/- 0.2 copies and a concomitant decrease of the normal derived T(14;15)6 from 2 copies to 0.9 +/- 0.2. All other autosomes except No. 14 showed only minor random variations, around the expected number of 4 copies. The tumor-derived chromosome 14 was amplified from the expected 2 to 3 copies. The low-tumorigenic hybrids showed the opposite pattern with a decrease in the number of the tumor-derived 15 chromosome from 3 to 2.6 +/- 0.1 and the maintenance of the two normal parent derived T(14;15)6 chromosomes. These findings suggest the existence of a qualitative difference between the 15 chromosomes derived from the tumor vs. the normal parent, due to mutation or proviral DNA insertion in the tumor-derived homologue. Amplification of the change locus and a decrease in the dosage of its normal counterpart appear to favor tumorigenicity.

Animals↗
PubMed1994

Frequent deletion in chromosome 4 and duplication of chromosome 15 in liver epithelial cells derived from long-term culture of C3H mouse hepatocytes.

Prolonged culture of hepatocytes isolated from mouse liver results in the spontaneous development of colonies of liver epithelial cells that can proliferate indefinitely in vitro. We established 5 such cell lines from C3H/HeJ mice (C3H) and 22 cell lines from C3H/HeJ x C57BL/6J F1 mice (C3B6F1) to investigate whether any specific karyotype alterations may be associated with the development of such cells. These lines retained some properties of hepatocytes as well as showing bile-duct-cell characteristics, and comprised mainly near-diploid and/or hypotetraploid cells. Karyotypic analysis of the C3H cell lines indicated that most cells have loss of chromosome 4 or deletion involving the C7 portion, while at least 1 (for near-diploid cells) or 2 (for hypotetraploid cells) copies of chromosome 4 were usually intact. In addition, gain of an extra chromosome 15 was frequently observed in these cell lines. Analysis of the microsatellite DNA polymorphic markers in 22 C3B6F1 lines revealed that a majority of them showed loss of heterozygosity (LOH) for, at least, 1 of 3 polymorphic loci on chromosome 4, but not for 2 loci on chromosomes 7 and 11. Mouse chromosomes 4 and 15, therefore, may contain genes related to the ability of such liver epithelial cells to grow indefinitely in vitro [The locus on chromosome 4 was designated as liver-cell immortalization (LCI) locus].

Animals↗
PubMed2002

Multiple human chromosomes carrying tumor-suppressor functions for the mouse melanoma cell line B16-F10, identified by microcell-mediated chromosome transfer.

Many tumor-suppressor genes are involved in the development and progression of cellular malignancy. To understand the functional role of tumor-suppressor genes in melanoma and to identify the human chromosome that carries these genes, we transferred individually each normal human chromosome, except for the Y chromosome, into the mouse melanoma cell line B16-F10, by microcell fusion. We examined the tumorigenicity of hybrid cells in nude mice and their in vitro growth properties. The introduction of human chromosomes 1 and 2 elicited a remarkable change in cell morphologic features, and cellular senescence was induced at seven to 10 population doublings. The growth rates of tumors derived from microcell hybrid clones containing introduced human chromosome 5, 7, 9, 10, 11, 13, 14, 15, 16, 19, 20, 21, 22, or X were significantly slower than that of the parental B16-F10 cells, whereas the introduction of other human chromosomes had no effect on the tumorigenicity of these cells. The majority of microcell hybrid clones that exhibited suppressed tumorigenicity also showed a moderate reduction in doubling time compared with B16-F10 cells. Microcell hybrid clones with an introduced human chromosome 5 showed complete suppression of in vitro-transformed phenotypes, including cell growth, saturation density, and colony-forming efficiency in soft agar. Thus, these results indicated the presence of many cell senescence-related genes and putative tumor-suppressor genes for the mouse melanoma cell line B16-F10 and showed in vitro that many tumor-suppressor genes control the phenotypes of transformed cells in the multistep process of neoplastic development.

Animals↗
PubMed1993

Chromosomal localization of mouse bullous pemphigoid antigens. BPAG1 and BPAG2: identification of a new region of homology between mouse and human chromosomes.

Two bullous pemphigoid antigens, BPAG1 and BPAG2, have been recently cloned and mapped to human chromosomes 6p12-p11 and 10q24.3, respectively. In this study, we localized the corresponding mouse genes by interspecific backcross analysis. Bpag-1 mapped to the proximal region of mouse chromosome 1, identifying a new region of homology between human chromosome 6 and mouse chromosome 1. Bpag-2 mapped to the distal end of mouse chromosome 19 in a region of homology to human chromosome 10q. These assignments confirm and extend the relationships between the human and the mouse chromosomes.

Amino Acid Sequence↗
PubMed1981

Protein-depleted chromosomes. I. Structure of isolated protein-depleted chromosomes.

Protein-depleted isolated Chinese hamster chromosomes have been obtained by different protein extraction procedures and examined by electron microscopy and SDS-polyacrylamide gel electrophoresis. Salt-resistant centromeric and telomeric structures are visible in protein-depleted chromosomes and the protein-depleted chromosomes appear to have a regular, longitudinal pattern in critical point dried preparations. The scaffold-like structure of protein-depleted chromosomes is highly affected by the ionic strength and composition of the extraction medium and by the spreading conditions. Nucleosomal histones of isolated chromosomes proved to be more sensitive to the sodium chloride treatment than histones of isolated chromatin. A small, but constant quantity of core histones was detected in 2 M salt extracted chromosomes and H3 and H4 histones of isolated chromosomes appeared to be resistant to the sodium deoxycholate treatment.

Animals↗
PubMed1980

Ultrastructural characterization of the sex chromosomes during spermatogenesis of spiders having holocentric chromosomes and a long diffuse stage.

An ultrastructural study has been made of spermatogenesis in two species of primitive spiders having holocentric chromosomes (Dysdera crocata, male X0 and Sergestria florentia X1X2O). Analysis of the meiotic prophase shows a scarcity or absence of typical leptotene to pachytene stages. Only in D. crocata have synaptonemal complex (SC) remnants been seen, and these occurred in nuclei with an extreme chromatin decondensation. In both species typical early prophase stages have been replaced by nuclei lacking SC and with their chromatin almost completely decondensed, constituting a long and well-defined diffuse stage. Only nucleoli and the condensed sex chromosomes can be identified. - In S. florentina paired non-homologous sex chromosomes lack a junction lamina and thus clearly differ from the sex chromosomes of more evolved spiders with an X1X20 male sex determination mechanism. In the same species, sex chromosomes can be recognized during metaphase I due to their special structural details, while in D. crocata the X chromosome is not distinguishable from the autosomes at this stage. - The diffuse stage and particularly the structural characteristics of the sex chromosomes during meiotic prophase are reviewed and discussed in relation to the meiotic process in other arachnid goups.

Animals↗
PubMed1988

Structure and function of Y chromosomal DNA. I. Sequence organization and localization of four families of repetitive DNA on the Y chromosome of Drosophila hydei.

The sequence organization of four different families of Y chromosomal repetitive DNA is characterized at three levels of spatial extension along the Y chromosome of Drosophila hydei. At the lowest level of resolution, DNA blot analysis of Y chromosomal fragments of different lengths and in situ hybridization experiments on metaphase chromosomes demonstrate the clustering of each particular sequence family within one defined region of the chromosome. At a higher level of resolution, family specific repeats can be detected within these clusters by crosshybridization within 10-20 kb long continuous stretches of cloned DNA in EMBL3 phages. At the highest level of resolution, detailed sequence analysis of representative subclones about 1 kb in length reveals a satellite-like head to tail arrangement of family specific degenerated subrepeats as the building scheme common to all four families. Our results provide the first comparative sequence analysis of three novel families of repetitive DNA on the long arm of the Y chromosome of D. hydei. Additional data are presented which support the existence of two related subfamilies of repetitive DNA on the short arm of the Y chromosome.

Animals↗
PubMed1991

Monoclonal antibodies specific for human chromosome 5 obtained with a monochromosomal hybrid can be used to sort out cells containing the chromosome with a FACS.

Using a human-mouse monochromosomal hybrid, BG15-6, that contains an intact human chromosome 5, we isolated four monoclonal antibodies, 2A10, 3H9, 5G9, and 6G12, as chromosome marker antibodies recognizing cell surface antigens specific for human chromosome 5. The binding patterns of these antibodies to BG15 subclones containing fragments of human chromosome 5 indicated that 2A10, 3H9, and 6G12 recognized the antigens produced by genes located on 5pter-q22, and that 5G9 recognized the antigen produced by a gene located on 5q23. Cells containing human chromosome 5 were very effectively sorted in a fluorescence-activated cell sorter (FACS) using monoclonal antibody 6G12. This method for sorting cells containing human chromosome 5 or an appropriate fragment of this chromosome from among human-rodent hybrid cells should be very useful in studies on gene expression, gene cloning and gene mapping.

Animals↗
PubMed1994

A chromosome painting method for human sperm chromosomes using fluorescent in situ hybridization.

A method of chromosome painting on human sperm chromosomes using fluorescent in situ hybridization (FISH) is introduced. Sperm chromosome slides were prepared after in vitro fertilization of hamster eggs with human spermatozoa. The slides were treated by RNase A before FISH. Chromosome 4 was clearly and specifically painted in a majority of sperm-derived metaphase plates after an application of whole chromosome painting DNA probes of this chromosome. This is the first report of successful painting on human sperm chromosomes.

Animals↗
PubMed1994

Drug-specific rearrangements of chromosome 12 in hydroxyurea-resistant mouse SEWA cells: support for chromosomal breakage model of gene amplification.

In order to investigate whether specific, nonrandom chromosome rearrangements were involved in the induction of hydroxyurea (HU) resistance in mouse SEWA cells, we undertook detailed cytogenetic analyses of three independently selected lines during the long-term treatment with HU. We found that cells with trisomy 12 had selective advantage during early steps of HU treatment. Subsequently, numerous rearrangements of chromosome 12 took place in each of the HU-resistant cell lines. More specifically, the proximal end of chromosome 12 (band A3) was frequently involved in breaks and fusions generating multicentric marker chromosomes. In situ hybridization showed that the functional Rrm2 gene was located in this particular region of chromosome 12. Furthermore, amplification and rearrangements of the structural gene Rrm2 were detected both at the chromosomal and at the molecular level. As discussed, the results of the cytogenetic analyses support the chromosomal breakage model of gene amplification.

Animals↗
PubMed1996

De novo chromosome formations by large-scale amplification of the centromeric region of mouse chromosomes.

Chromosomes formed de novo which originated from the centromeric region of mouse chromosome 7, have been analysed. These new chromosomes were formed by apparently similar large-scale amplification processes, and are organized into amplicons of approximately 30 Mb. Centromeric satellite DNA was found to be the constant component of all amplicons. Satellite DNA sequences either bordered the large euchromatic amplicons (E-type amplification), or made up the bulk of the constitutive heterochromatic amplicons (H-type amplification). Detailed analysis of a heterochromatic megachromosome formed de novo by an H-type amplification revealed that it is composed of a tandem array of 10-12 large (approximately 30 Mb) amplicons each marked with integrated "foreign' DNA sequences at both ends. Each amplicon is a giant palindrome, consisting of two inverted doublets of approximately 7.5-Mb blocks of satellite DNA. Our results indicate that the building units of the pericentric heterochromatin of mouse chromosomes are approximately 7.5-Mb blocks of satellite DNA flanked by non-satellite sequences. We suggest that the formation de novo of various chromosome segments and chromosomes seen in different cell lines may be the result of large-scale E- and H-type amplification initiated in the pericentric region of chromosomes.

Animals↗
PubMed2002

Microsatellite analysis of wheat chromosome 2D allows the reconstruction of chromosomal inheritance in pedigrees of breeding programmes.

The dwarfing gene Rht8 and the photoperiodic insensitivity gene Ppd-D1 are linked on the short arm of chromosome 2D of bread wheat and play an important role in determining the geographic adaptation of modern wheat varieties. The genes are believed to originate from the old Japanese variety 'Akakomugi' and have been distributed throughout the world by diverse breeding programmes. Twelve microsatellite loci previously mapped on wheat chromosome 2D were used for a retrospective analysis of 59 wheat varieties with known pedigree, to trace the transmittance of the chromosomal region around these genes during extended breeding programmes. Within the range of the screened varieties 100 alleles were detected at the 12 microsatellite loci. For each microsatellite locus, a screen over varieties was performed to find the alleles corresponding to the parental variety 'Akakomugi'. A comparison of wheat varieties carrying the 192-bp allele, at locus Xgwm261-2D which is diagnostic for the presence of the gene Rht8, with the varieties without Rht8, showed linkage disequilibrium of 'Akakomugi' alleles for a segment of chromosome 2D which comprised at least 28 cM. Selection was accompanied with a linkage drag of 'Akakomugi' alleles in the neighbouring loci to Rht8. A diminution of the segment of chromosome 2D originating from 'Akakomugi' during several pedigree generations was observed. Varieties of the early generations were found to carry the whole short arm of chromosome 2D of 'Akakomugi', while the varieties of further selections possessed smaller segments including the diagnostic allele at locus Xgwm261-2D. Our results demonstrate that microsatellites can be successfully used for studying the inheritance of chromosomes within pedigrees of breeding programmes.

Chromosome Mapping↗
PubMed2004

Sequences associated with A chromosome centromeres are present throughout the maize B chromosome.

Maize chromosome spreads containing the supernumerary B chromosome were hybridized with probes from various repetitive elements including CentC, CRM, and CentA, which have been localized to centromeric regions on the A chromosomes. Repetitive elements that are enriched or found exclusively near the centromeres of A chromosomes hybridized to many sites distinct from the centromere on the B chromosome. To examine whether these elements recruit kinetochore proteins at locations other than the canonical B centromere, cells were labeled with antibodies against CENH3, a key kinetochore protein. No labeling was detected outside the normal centromere and no evidence of B chromosome holocentromeric activity was observed. This finding suggests that, as in other higher eukaryotes, DNA sequence alone is insufficient to dictate kinetochore location in plants. Additionally, examination of the B centromere region in pachytene chromosomes revealed that the B-specific element ZmBs hybridizes to a much larger region than the site of hybridization of CentC, CRM, and CentA and the labeling by anti-CENH3 antibodies.

Centromere↗
PubMed1997

Chromosome-specific alpha-satellite DNA from the centromere of chimpanzee chromosome 4.

The centromeric regions of human and primate chromosomes are characterized by diverged subsets of tandemly repeated alpha-satellite DNA. Comparison of the alpha-satellites on known homologous chromosomes in human and chimpanzee provides insight into the very rapid evolution of satellite DNA sequences and the mechanisms that shape complex genomes. By using oligonucleotide primers specific for a conserved region of human alpha-satellite DNA, we have amplified a chromosome-specific alpha-satellite subset from the chimpanzee genome by the polymerase chain reaction. Fluorescence in situ hybridization showed that clones palphaPTR4N and palphaPTR4H are homologous to sequences at the centromere of the chimpanzee chromosome 4. This alpha-satellite subset is organized as a series of pentameric (higher-order) repeats, operationally defined by digestion of genomic DNA with HaeIII, MboI, RsaI, SstI, and XbaI. The lengths of four independent centromeric arrays measured by pulsed-field gel electrophoresis varied between 800 and 3,500 kb (mean = 1,850 kb, SD = 1,000 kb). Nucleotide sequence analysis demonstrated that chimpanzee chromosome 4 alpha-satellite is most closely related to the suprachromosomal subfamily II, which is evolutionarily different from the subfamily I to which the alpha-satellite on the homologous human chromosome 5 belongs. This implies that the human-chimpanzee sequence divergence has not arisen from a common ancestral alpha-satellite repeat(s) but instead represents concerted evolution of distinct repeats on homologous chromosomes.

Animals↗
PubMed2004

Microcolinearity between a 2-cM region encompassing the grain protein content locus Gpc-6B1 on wheat chromosome 6B and a 350-kb region on rice chromosome 2.

The conservation of the linear order (colinearity) of genetic markers along large chromosome segments in wheat and rice is well established, but less is known about the microcolinearity between both genomes at subcentimorgan distances. In this study we focused on the microcolinearity between a 2.6-cM interval flanked by markers Xcdo365 and Xucw65 on wheat chromosome 6B and rice chromosome 2. A previous study has shown that this wheat segment includes the Gpc-6B1 locus, which is responsible for large differences in grain protein content (GPC) and is the target of a positional cloning effort in our laboratories. Twenty-one recombination events between Xcdo365 and Xucw65 were found in a large segregating population (935 gametes) and used to map 17 genes selected from rice chromosome 2 in the wheat genetic map. We found a high level of colinearity between a 2.1-cM region flanked by loci Xucw75 and Xucw67 on wheat chromosome 6B and a 350-kb uninterrupted sequenced region in rice chromosome arm 2S. Colinearity between these two genomes was extended to the region proximal to Xucw67 (eight colinear RFLP markers), but was interrupted distal to Xucw75 (six non-colinear RFLP markers). Analysis of different comparative studies between rice and wheat suggests that microcolinearity is more frequently disrupted in the distal region of the wheat chromosomes. Fortunately, the region encompassing the Gpc-6B1 locus showed an excellent conservation between the two genomes, facilitating the saturation of the target region of the wheat genetic map with molecular markers. These markers were used to map the Gpc-6B1 locus into a 0.3-cM interval flanked by PCR markers Xucw79 and Xucw71, and to identify five candidate genes within the colinear 64-kb region in rice.

Chromosomes, Plant↗
PubMed2004

Several chromosomes involved in translocations with chromosome 5 shown with fluorescence in situ hybridization in patients with malignant myeloid disorders.

In many patients with myelodysplastic syndromes or acute myeloid leukemia, complex chromosome aberrations can be seen, among which aberrations of chromosome 5 constitute a substantial part. With conventional cytogenetic technique, these aberrations are often identified as deletions or monosomy 5. We analyzed nine patients who, under conventional cytogenetic analysis, showed deletion or monosomy 5. We used fluorescence in situ hybridization with whole-chromosome painting probes to identify the counterpart chromosome and locus-specific identifiers for 5q31 and 5q33 approximately q34. A deletion of 5q was found concomitant with unbalanced translocations. Our results and cases from the literature showed that material from chromosome 5 could be translocated to almost all chromosomes. All patients but one had short survival; this one patient had a preserved 5q31 and 5q33 approximately q34 but a deletion of the q-arm more centromeric than these bands. In eight of the nine patients, further 14 translocations were revealed, not involving chromosome 5.

Chromosomes, Human, Pair 5↗