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PubMed2026

Chromosome engineering to correct a complex rearrangement on Chromosome 8 reveals the effects of 8p syndrome on gene expression and neural differentiation.

Chromosomal rearrangements on the short arm of Chromosome 8 cause 8p syndrome, a rare developmental disorder characterized by neurodevelopmental delays, epilepsy, and cardiac abnormalities. Although significant progress has been made in managing the symptoms of 8p syndrome and other conditions caused by large-scale chromosomal aneuploidies, no therapeutic approach has yet been demonstrated to target the underlying disease-causing chromosome. Here, we establish a two-step approach to eliminate the abnormal copy of Chromosome 8 and restore euploidy in cells derived from an individual with a complex rearrangement of Chromosome 8p. Transcriptomic analysis revealed 361 differentially expressed genes between the proband and the euploid revertant, highlighting genes both within and outside the 8p region that may contribute to 8p syndrome pathology. Furthermore, we demonstrate that the proband exhibits a significant defect in neural differentiation that could be partially rescued by treatment with small-molecule inhibitors of cell death. Our work demonstrates the feasibility of using chromosome engineering to correct complex aneuploidies in vitro and establishes a platform to further dissect the pathophysiology of 8p syndrome and other conditions caused by chromosomal rearrangements.

Humans↗
PubMed1995

Six loci mapped on to human chromosome 2p are assigned to sheep chromosome 3p.

Six loci, apoliproprotein B (including Ag(x) antigen), immunoglobulin kappa constant region (IGKC), luteinizing hormone/choriogonadotrophin receptor, avian myelocytomatosis viral related oncogene, neuroblastoma derived, ornithine decarboxylase, and proopiomelanocortin (adrenocorticotropin/beta-lipotropin) (POMC), were newly assigned to sheep chromosome 3p using a chromosomally characterized minipanel of sheep-hamster cell hybrids. Isotopic in situ hybridization of IGKC to sheep chromosome 3p22-p17 is reported, confirming the cell hybrid assignment. As these loci are all known to map to human chromosome 2p, this study demonstrates that this chromosomal segment is extensively conserved in sheep. Only POMC has been previously assigned to cattle chromosome 11, which is the equivalent of sheep chromosome 3p. Therefore, we predict that the other loci assigned in this study to sheep 3p are likely to be located on cattle 11. The provisional assignment of an additional locus, annexin-like to sheep chromosome 3p is also reported.

Animals↗
PubMed1992

Resolution of chromosomes III and VI of Aspergillus nidulans by pulsed-field gel electrophoresis shows that the penicillin biosynthetic pathway genes pcbAB, pcbC, and penDE are clustered on chromosome VI (3.0 megabases).

An improved electrophoretic molecular karyotype of Aspergillus nidulans ATCC 28901 has been obtained by contour-clamped electric field gel electrophoresis, which separates seven chromosomal bands and allows resolution of chromosomes III and VI. The three genes of the penicillin biosynthetic pathway, pcbAB, pcbC, and penDE, encoding alpha-aminoadipyl-cysteinyl-valine synthetase, isopenicillin N synthase, and isopenicillin N acyltransferase, respectively, are clustered together on a chromosome of 3.0 Mg, corresponding to linkage group VI, whereas the argB gene was located on a chromosome of 3.4 Mb, corresponding to linkage group III. Three other strains of A. nidulans contained a modified chromosome III of about 3.1 Mb that overlaps with chromosome VI, forming a doublet. Resolution of chromosomes III and VI in strain ATCC 28901 allowed unequivocal mapping of the penicillin gene cluster on chromosome VI of A. nidulans.

Acyltransferases↗
PubMed1964

GENE TRANSFER BY F' STRAINS OF ESCHERICHIA COLI. IV. EFFECT OF A CHROMOSOMAL DELETION ON CHROMOSOME TRANSFER.

Pittard, James (Yale University, New Haven, Conn.), and T. Ramakrishnan. Gene transfer by F' strains of Escherichia coli. IV. The effect of a chromosomal deletion on chromosome transfer. J. Bacteriol. 88:367-373. 1964.-Evidence is presented that in an F' strain of Escherichia coli. AB1206, the chromosomal region corresponding to the merogenote of F(14) is deleted. AB1206 differs from all other F' strains in its stability and in its relative inability to transfer chromosomal markers under conditions in which transfer of the merogenote occurs at a frequency of 100%. Its stability can be accounted for by the fact that the loss of the F merogenote, which contains approximately 10% of the genetic information of the cell, would be a lethal event. The failure of AB1206 to transfer chromosomal markers, except at very low frequencies, can be explained in terms of the crossover model proposed to explain chromosome transfer by F' strains, since the homologous chromosomal region is missing in this strain. The conclusion that the chromosomal region is deleted is strengthened by the finding that the different enzymes coded for by the genes on F(14) are present in AB1206 at the level found in haploid strains, but have double this activity in homozygous diploids carrying F(14).

Chromosomes↗
PubMed2005

Suppressors of Bir1p (Survivin) identify roles for the chromosomal passenger protein Pic1p (INCENP) and the replication initiation factor Psf2p in chromosome segregation.

Fission yeast Bir1p/Cut17p/Pbh1p, the homolog of human Survivin, is a conserved chromosomal passenger protein that is required for cell division and cytokinesis. To study how Bir1p promotes accurate segregation of chromosomes, we generated and analyzed a temperature-sensitive allele, bir1-46, and carried out genetic screens to find genes that interact with bir1(+). We identified Psf2p, a component of the GINS complex required for DNA replication initiation, as a high-copy-number suppressor of the bir1-46 growth defect. Loss of Psf2p function by depletion or deletion or by use of a temperature-sensitive allele, psf2-209, resulted in chromosome missegregation that was associated with mislocalization of Bir1p. We also found that the human homolog of Psf2p, PSF2, was required for proper chromosome segregation. In addition, we observed that high-copy-number expression of Pic1p, the fission yeast homolog of INCENP (inner centromere protein), suppressed bir1-46. Pic1p exhibited a localization pattern typical of chromosomal passenger proteins. Deletion of pic1(+) caused chromosome missegregation phenotypes similar to those of bir1-46. Our data suggest that Bir1p and Pic1p act as part of a conserved chromosomal passenger complex and that Psf2p/GINS indirectly affects the localization and function of this complex in chromosome segregation, perhaps through an S-phase role in centromere replication.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Meiotic chromosome structure. Kinetochores and chromatid cores in standard and B chromosomes of Arcyptera fusca (Orthoptera) revealed by silver staining.

The behaviour of two chromosome structures in silver-stained chromosomes was analyzed through the first meiotic division in spermatocytes of the acridoid species Arcyptera fusca. Results showed that at diakinesis kinetochores and chromatid cores are individualized while they associate in bivalents of metaphase I; only kinetochores and distal core spots associate in the sex chromosome. Metaphase I is characterized by morphological and localization changes of both kinetochores and cores which define the onset of anaphase I. These changes analyzed in both autosomes and in the sex chromosome allow us to distinguish among three different substages in metaphase I spermatocytes. B chromosomes may be present as univalents, bivalents, or trivalents. Metaphase I B univalents are characterized by separated cores except at their distal ends and individualized and flat sister kinetochores. At anaphase I sister kinetochores of lagging B chromatids remain connected through a silver-stained strand. The behaviour of cores and kinetochores of B bivalents is identical with that found in the autosomal bivalents. The differences in the morphology of kinetochores of every chromosome shown by B trivalents at metaphase I may be related to the balanced forces acting on the multivalent. The results show dramatic changes in chromosome organization of bivalents during metaphase I. These changes suggest that chromatid cores are not involved in the maintenance of bivalents. Moreover, the changes in morphology of kinetochores are independent of the stage of meiosis but correlate with the kind of division (amphitelic-syntelic) that chromosomes undergo.

Animals↗
PubMed2005

High susceptibility of chromosome 16 to radiation-induced chromosome rearrangements in human lymphocytes under in vivo and in vitro exposure.

The aim of the present study was to investigate whether chromosome 16p presents breakpoint regions susceptible to radiation-induced rearrangements. The frequencies of translocations were determined by fluorescence in situ hybridization (FISH) using cosmid probes C40 and C55 mapping on chromosome 16p, and a chromosome 16 centromere-specific probe (pHUR195). Peripheral lymphocytes were collected from normal individuals and from seven victims of 137Cs in the Goiania (Brasil) accident (absorbed doses: 0.8-4.6 Gy) 10 years after exposure. In vitro irradiated lymphocytes (3 Gy) were also analyzed. The mean translocation frequency/cell obtained for the 137Cs exposed individuals was 2.4-fold higher than the control value (3.6 x 10(-3) +/- 0.001), and the in vitro irradiated lymphocytes showed a seven-fold increase. The genomic translocation frequencies (FGs) were calculated by the formula Fp = 2.05 fp(1-fp)FG (Lucas et al., 1992). For the irradiated lymphocytes and victims of 137Cs, the FGs calculated on the basis of chromosome 16 were 2- to 8-fold higher than those for chromosomes 1, 4 and 12. Our results indicate that chromosome 16 is more prone to radiation-induced chromosome breaks, and demonstrate a non-random distribution of induced aberrations. This information is valuable for retrospective biological dosimetry in case of human exposure to radiation, since the estimates of absorbed doses are calculated by determining the translocation frequency for a sub-set of chromosomes, and the results are extrapolated to the whole genome, assuming a random distribution of induced aberrations. Furthermore, the demonstration of breakpoints on 16p is compatible with the reports about their involvement in neoplasias.

Adult↗
PubMed1989

Determination of the breakpoints of 1;7 translocations in myelodysplastic syndrome by in situ hybridization using chromosome-specific alpha satellite DNA from human chromosomes 1 and 7.

A whole-arm translocation involving the short arm of chromosome 7 and the long arm of chromosome 1 occurs nonrandomly in myelodysplastic syndrome and acute nonlymphocytic leukemia. In situ hybridization, using alpha satellite DNA specific for the centromeric regions of chromosomes 1 (probe pSD1-1) and 7 (probe p21-4), was performed to determine the exact breakpoints of the translocation. Both probes hybridized to the centromeric region of the translocation chromosome in metaphases from two patients with myelodysplastic syndrome. Both probes hybridized with approximately equal strength to either chromosome 1 or 7 and to the 1;7 translocation chromosome, suggesting that the t(1;7) had retained the chromosome-specific alpha satellite DNA from both chromosomes. These studies permit us to propose a new description, t(1;7)(cen;cen), for this translocation.

Aged↗
PubMed1994

Isolation and mapping of 328 new cosmid markers on human chromosome 8: construction of a high-resolution cytogenetic map of chromosome 8 with 416 markers.

We have determined the chromosomal localizations of newly isolated cosmids by fluorescent in situ hybridization (FISH) on prometaphase R-banded chromosomes and have constructed a high-resolution cytogenetic map for human chromosome 8 with 416 cosmid markers, including 328 new markers and 88 reported previously. Of the 416 markers, 229 were mapped to the long arm of chromosome 8, 181 to the short arm, and 6 to the centromere. Although the clones were scattered throughout the chromosome, they were concentrated in R-positive bands. Since the estimated physical length of chromosome 8 is 135 Mb, the overall average distance between loci is 320 kb, but the average separation of loci on R-positive bands is nearly 130-200 kb. This cytogenetic map will serve as a resource for efforts to characterize chromosomal and molecular aberrations involved in cancers, to clone genes associated with hereditary diseases, and to construct a detailed physical map of large electrophoretic fragments and/or contiguous cosmids and yeast artificial chromosomes.

Animals↗
PubMed1995

Chromosomal painting shows that "marked chromosomes" in lesser apes and Old World monkeys are not homologous and evolved by convergence.

Cytogeneticists have long held that the single pair of metacentric, NOR-bearing "marked chromosomes" in lesser apes (Hylobatidae) and Old World monkeys (Cercopithecidae) are homologous. Hylobatids have sometimes been excluded from Hominoidea (great apes and humans) and phylogenetically allied with the lower primates, primarily on the basis of this shared "trait." However, in situ hybridization of human chromosome-specific DNA probes to chromosomes of Hylobates lar, H. syndactylus, H. concolor, Cercopithecus aethiops, Macaca fuscata, Colobus guereza, and Presbytis cristata showed that the so-called "marked chromosomes" in Hylobatidae and Cercopithecidae evolved by convergence. Therefore, "marked chromosomes" cannot be used to exclude gibbons from Hominoidea or to link Hylobatidae with monkeys. Chromosomal painting is a powerful tool to resolve problems of chromosomal homology and helps eliminate phylogenetic errors due to confusing convergence with homology. Chromosomal painting improves the confidence in using cytogenetic data for evolutionary studies, especially in phylogeny and taxonomy.

Animals↗
PubMed1996

Chromosomal evolution in duiker antelope (Cephalophinae: Bovidae): karyotype comparisons, fluorescence in situ hybridization, and rampant X chromosome variation.

Fluorescence in situ hybridization (FISH) and conventional banding techniques were used to identify patterns of similarity among the genomes of six species of antelope, subfamily Cephalophinae. The G-banded euchromatic portions of the autosomes were invariable in all species; however, significant modifications of the X chromosomes were detected. Two of the taxa, Cephalophus maxwellii and C. monticola, were characterized by acrocentric X's, while X chromosome morphology varied from submetacentric to metacentric in the remaining species (C. dorsalis, C. natalensis, Sylvicapra grimmia, and C. silvicultor). The short arm of the X was heterochromatic in each species. Total genomic DNAs from these antelope were used as hybridization probes against Cephalophus metaphase chromosomes and resulted in robust fluorescence in the pericentromeric region of each autosome and in the heterochromatic short arm of the X chromosome, indicating complimentarity of DNA sequences in these regions. Conversely, chromosome painting involving genomic DNAs derived from the subfamilies Alcelaphinae (Pygargus dorcas) and Neotraginae (Oreotragus oreotragus) showed a marked absence of hybridization at these sites. Additionally, X chromosome comparisons between the Cephalophinae and Bovinae (represented by Bos taurus) revealed two euchromatic pericentric inversions which had occurred since their common ancestry. There is good G-band homoeology between the inverted cattle chromosome region Xq12 --> q34 and most of the proximal portion of Xq in duikers, as well as between the distal third of the duiker Xq and the cattle Xp. The latter rearrangement was further confirmed by in situ hybridization using a probe containing an insert spanning bands p12 to p14 of the cattle X chromosome.

Animals↗
PubMed1997

Map integration at human chromosome 10: molecular and cytogenetic analysis of a chromosome-specific somatic cell hybrid panel and genomic clones, based on a well-supported genetic map.

Well-characterized, chromosome-specific somatic cell hybrid panels are powerful tools for the analysis of the human genome. We have characterized a panel of human x hamster somatic cell hybrids retaining fragments of human chromosome 10 by fluorescence in situ hybridization and associated them to genetic markers. Most of the hybrids were generated by the radiation-reduction method, starting from a chromosome 10-specific monochromosomal hybrid, whereas some were collected from hybrids retaining chromosome 10-specific fragments as a result of spontaneous in vitro rearrangements. PCR was used to score the retention of 57 microsatellite markers evenly distributed along a well-supported framework genetic map containing 149 loci uniquely placed at 69 anchor points (odds exceeding 1,000:1), with an average spacing of 2.8 cM. As an additional resource for genomic studies involving human chromosome 10, we report the cytogenetic localization of a series of YAC and PAC clones recognized by at least one genetic marker. Somatic cell hybrids provide a powerful source of partial chromosome paints useful for detailed clinical cytogenetic and primate chromosome evolution investigations. Furthermore, correlation of the above physical, genetic, and cytogenetic data contribute to an emerging consensus map of human chromosome 10.

Animals↗
PubMedDate not supplied

Liability to chromosome damage in lymphocytes of "cancer family" subjects: a study of spontaneous and induced chromosomal fragility.

Spontaneous chromosomal fragility was detected in seven tumor patients and one healthy member from two families with a high recurrence of cancer. Major chromosome lesions, such as terminal deletions and rearranged chromosomes, were found at levels significantly higher than those reported for control individuals. The prevalence of these aberrations in comparison to minor ones (chromosome gaps and chromatid breaks) in this group of patients seems to indicate that the fragility observed is the end-point of a process of chromosomal instability, which may have already been brought to expression. Study of other parameters of genetic instability in the most unstable karyotypes showed that the chromosome damage observed was neither paralleled by abnormal SCE frequency nor sustained by defective DNA repair mechanisms or expression of inherited or constitutional fragile sites. As all the subjects investigated here had previously been shown to display intraindividual variations in the C-banded region of chromosome 1, it is possible that spontaneous fragility and acquired C-heterochromatin polymorphism may be markers that, combined with chromosomal instability, create genetic predisposition to cancer.

Adult↗
PubMed2005

Chromosome 18 pairing behavior in human trisomic oocytes. Presence of an extra chromosome extends bouquet stage.

Little is known about the first meiotic prophase stages in the human female because these occur during fetal life, and only a few studies have addressed aneuploid human oocytes. In this paper, the synaptic process in the meiotic prophase in three 47, XX+18 cases is analyzed. A complete study of the dynamics of centromeres and telomeres, cohesin core and synapsis development in aneuploid female meiosis was performed. Investigation of chromosome dynamics in prophase of trisomy 18 oocytes show that these events follow the major patterns seen earlier in euploid oocytes. However, there is a significant delay in the resolution of bouquet topology which could relate to the presence of a surplus chromosome 18 axial element in zygotene oocytes. Pachytene oocytes displayed normal synapsis among the three chromosome 18s. However, in some oocytes the surplus chromosome 18 core was aligned to the bivalent 18. As ataxia telangiectasia and Rad3 related kinase (ATR) has been described as a marker for late-pairing chromosomes in mice, ATR distribution was analyzed in human meiocytes--spermatocytes, euploid oocytes and trisomic oocytes. In contrast to the observations made in mice, no preferential staining for late-pairing chromosomes was observed in humans. In the cases studied, bivalent synapses progressed as in a normal ovary, contrasting with the hypothesis that a surplus chromosome can modify pairing of other chromosomes.

Ataxia Telangiectasia Mutated Proteins↗
PubMed1992

A molecular deletion of distal chromosome 4p in two families with a satellited chromosome 4 lacking the Wolf-Hirschhorn syndrome phenotype.

We report two families with a satellited chromosome 4 short arm (4ps). Satellites and stalks normally occur on the short arms of acrocentric chromosomes; however, the literature cites several reports of satellited nonacrocentric chromosomes, which presumably result from a translocation with an acrocentric chromosome. This is the first report of 4ps chromosomes. Our families are remarkable in that both unaffected and affected individuals carry the 4ps chromosome. The phenotypes observed in affected individuals, although dissimilar, were sufficient to encourage a search for a deletion of chromosome 4p. By Southern blot analysis and fluorescence in situ hybridization, a deletion of material mapping approximately 150 kb from chromosome 4pter was discovered. This deletion is notable because it does not result in the Wolf-Hirschhorn syndrome and can result in an apparently normal phenotype. We speculate that homology between subterminal repeat sequences on 4p and sequences on the acrocentric short arms may explain the origin of the rearrangement and that position effect may play a role in the expression of the abnormal phenotype.

Abnormalities, Multiple↗
PubMed1988

[Genome mapping of the silver fox. I. Determination of the chromosomal location of 8 fox genes and the search for homologous regions on fox and human chromosomes].

Twenty-three silver fox-Chinese hamster somatic cell hybrids were analysed for the expression of fox enzyme loci and the segregation of fox chromosomes. This analysis made it possible to assign the gene PGD to chromosome 2, MDH2 to chromosome 3. NP to chromosome 10. APRT, ENO1, PGM1 to chromosome 12, MDH1 and IDH1 to chromosome 16. Possible use of the above-mentioned clone panel for fox gene mapping is analysed. An attempt to reveal homologous regions on fox and human chromosomes was made by comparative analysis of prometaphase fox and human chromosomes containing the homologous genes. The means and perspectives of verification of the hypothesis proposed are discussed.

Animals↗
PubMed1987

Similarity in dynamics of single or double minute chromosomes incidence and number of chromosomal aberrations during long-term treatment of a human cell line with methotrexate.

The human cell line VUPT was treated with gradually increasing concentrations of methotrexate for 500 days. During this period of time the frequency of cells containing single or double minute chromosomes and the number of chromosomal aberrations were estimated. When the concentration of the drug increased, so did the frequency of cells with minute chromosomes, but after several days of adaptation to the given concentration of the drug the minute chromosomes disappeared again. The dynamics of the frequency of chromosomal aberrations resembled that of the minute chromosomes, but the change in the former cytogenetic parameter generally preceded corresponding changes in the latter. The results indicate a possible relationship between the development of chromosomal aberrations and the formation of minute chromosomes.

Cell Line↗
PubMed1998

Quantitative FISH by image cytometry for the detection of chromosome 1 imbalances in breast cancer: a novel approach analyzing chromosome rearrangements within interphase nuclei.

Interphase cytogenetics have become a widespread tool for investigation of chromosome rearrangements in solid tumors. The most recurrent chromosome alteration within breast cancer affects chromosome 1, leading principally to gain of the long arm and/or loss of the short arm. We have developed a new method for detection of chromosome 1 arm imbalances in interphase nuclei. The method is based on quantitation of the fluorescence signals emitted by the hybridized two-color paintings of the short and long arms using image cytometry. The chromosome arm imbalance was determined by calculating the ratio of both fluorescence emissions of each arm. The ratio of the paintings of normal lymphocytes was used as a reference. Three breast cancer cell lines, 13 fresh tumor samples, and 6 fine-needle samplings of breast cancer were analyzed using an automated image cytometer. Whenever possible, classic cytogenetics and in situ hybridization on metaphases were performed as controls. Fluorescence ratios representing the imbalances of chromosome 1 arms with values between 1 and 3.2 were measured. Data between classic cytogenetics and interphase cytogenetics were well-correlated (r = 0.89). This method, which enables an easy detection of intrachromosomal imbalances without need of metaphase preparations, detects malignant cells and can be extended to other carcinomas for which chromosome 1 arm imbalances are recurrent or chromosome alterations specific of other malignancies. In comparison to other interphase fluorescence in situ hybridization techniques, it avoids every spot scoring problem encountered when using centromeric probes and the difficulties in interpreting structural rearrangements.

Adult↗