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PubMed1996

Genomic structure, chromosomal localization, start of transcription, and tissue expression of the human p40-phox, a new component of the nicotinamide adenine dinucleotide phosphate-oxidase complex.

p40-phox is a newly isolated cytosolic component of the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase that copurifies with p67-phox. Although its function is not well defined, preliminary evidence indicates that it is a component of the cytosolic complex. We report the characterization of the human p40-phox gene, which is single copy and spans approximately 18 kb with 10 exons. Based on fluorescent in situ hybridization (FISH) studies and analysis of somatic hybrid cell lines, the chromosomal location of p40-phox is human chromosome 22q13.1. The start of transcription has been mapped to bp -156. The expression of p40-phox message is restricted to hematopoietic cells. In addition to identifying the mRNA transcript on Northern blot analysis in cells known to express components of the NADPH-oxidase, polymorphonuclear leukocytes, monocytes, B lymphoblastoid cell lines, and eosinophils, p40-phox is also expressed in two other cell types of white cell lineage, mast cells, and basophils. In addition, the mRNA for p40-phox is expressed in megakaryocytic cells, but not in erythroid cells.

Base Sequence↗
PubMed1997

Recurring structural chromosome abnormalities in peripheral blood lymphocytes of patients with mycosis fungoides/Sézary syndrome.

Cytogenetic analysis was performed on peripheral blood lymphocyte cultures from 19 patients with mycosis fungoides (MF)/Sézary syndrome (SS) stimulated with either phytohemagglutinin, a conventional mitogen, or a combination of interleukin-2 (IL-2) plus IL-7. The use of both PHA-stimulated and IL-2 plus IL-7-stimulated cultures enhanced the ability to identify clonal abnormalities. Clonal abnormalities were observed in 11 patients (53%) including one with monosomy for the sex chromosome as the sole abnormality. Five of the 11 patients with clonal abnormalities had normal peripheral white blood cell counts, indicating detectability of clones in the absence of frankly leukemic disease. The presence of clonal abnormalities correlated with advanced stage disease and a significantly reduced survival duration from the time of cytogenetic studies. Clonal abnormalities involving chromosomes 1 and 8 were observed in six cases. In five cases with aberrations of chromosome 1, loss of material involved the region between 1p22 and 1p36. In an additional case, a reciprocal translocation involving 1p33 was observed. Clonal abnormalities involving chromosomes 10 and 17 were observed in 5 cases, clonal abnormalities involving chromosome 2 in 4 cases, and clonal abnormalities involving chromosomes 4, 5, 6, 9, 13, 15, 19, and 20 in 3 cases. In 2 cases a der(8)t(8;17)(p11;q11) was observed. Regions of the genome that encode T-cell receptors were not involved in abnormalities. The region between 1p22 and 1p36 is identified as a region of the genome that requires detailed analysis toward the identification of potential gene(s) involved in the process of malignant transformation and/or progression in MF/SS.

Adult↗
PubMed2001

Human-specific duplication and mosaic transcripts: the recent paralogous structure of chromosome 22.

In recent decades, comparative chromosomal banding, chromosome painting, and gene-order studies have shown strong conservation of gross chromosome structure and gene order in mammals. However, findings from the human genome sequence suggest an unprecedented degree of recent (<35 million years ago) segmental duplication. This dynamism of segmental duplications has important implications in disease and evolution. Here we present a chromosome-wide view of the structure and evolution of the most highly homologous duplications (> or = 1 kb and > or = 90%) on chromosome 22. Overall, 10.8% (3.7/33.8 Mb) of chromosome 22 is duplicated, with an average sequence identity of 95.4%. To organize the duplications into tractable units, intron-exon structure and well-defined duplication boundaries were used to define 78 duplicated modules (minimally shared evolutionary segments) with 157 copies on chromosome 22. Analysis of these modules provides evidence for the creation or modification of 11 novel transcripts. Comparative FISH analyses of human, chimpanzee, gorilla, orangutan, and macaque reveal qualitative and quantitative differences in the distribution of these duplications--consistent with their recent origin. Several duplications appear to be human specific, including a approximately 400-kb duplication (99.4%-99.8% sequence identity) that transposed from chromosome 14 to the most proximal pericentromeric region of chromosome 22. Experimental and in silico data further support a pericentromeric gradient of duplications where the most recent duplications transpose adjacent to the centromere. Taken together, these data suggest that segmental duplications have been an ongoing process of primate genome evolution, contributing to recent gene innovation and the dynamic transformation of genome architecture within and among closely related species.

Animals↗
PubMed1990

Cytogenetics of breast cancer.

Chromosome counts were performed on 1,100 cells from 17 malignant breast carcinomas and on 168 cells of four normal tissue samples after amethopterin treatment and G-banding. Karyotypes were established from 216 cells of 11 tumor-derived cultures and from 47 cells of four nonmalignant tissue-derived cultures. Karyotypes of cells from nonmalignant samples showed a normal diploid chromosomal constitution with no consistent loss or gain of a specific chromosome. Structural chromosomal abnormalities were not observed. Tumor-derived cultures could be distinguished from normal cultures on the basis of a significantly increased incidence of numerical changes and structural chromosomal aberrations. In nine of 11 tumor-derived cultures, numerically normal cells were shown to be pseudodiploid, with frequencies ranging to 43% (mean, 13.2%) of the diploid cells. In agreement with previous reports, cytogenetic analyses showed predominantly diploid cells. Clonal numerical changes of chromosomes 17, 18, 20, and 21 could be detected in three tumor samples. Clonal structural abnormalities could be observed in two of 11 analyzed tumours. A t(6;12)(p21;p13) and an enlarged chromosome 7 (7q+) were found in a patient with invasive ductal carcinoma. An inversion of chromosome 7 [inv(7)(q11.2q32)] was observed in one case, also diagnosed as invasive ductal carcinoma. The significance of these findings in relation to clinical data is discussed.

Adult↗
PubMed1997

[Structural-functional chromosome organization in response to stress].

Published data and the results of experiments conducted at the Laboratory of Genetics of Higher Nervous Activity, Pavlov Institute of Physiology, on the effect of stress on chromosome structure and function are reviewed briefly. Experiments were performed on inbred rats selected for excitation threshold and mutant Drosophila with altered metabolism of secondary mediators.

Adaptation, Physiological↗
PubMed2003

A new FISH assay to simultaneously detect structural and numerical chromosomal abnormalities in mouse sperm.

De novo aberrations in chromosome structure represent important categories of paternally transmitted genetic damage. Unlike numerical abnormalities, the majority of de novo structural aberrations among human offspring are of paternal origin. We report the development of a three-color fluorescence in situ hybridization (FISH) assay (CT8) to detect mouse sperm carrying structural and numerical chromosomal abnormalities. The CT8 assay uses DNA probes for the centromeric and telomeric regions of chromosome 2, and a probe for the subcentromeric region of chromosome 8. The CT8 assay was used to measure the frequencies of sperm carrying certain structural aberrations involving chromosome 2 (del2ter, dup2ter, del2cen, dup2cen), disomy 2, disomy 8, and sperm diploidy. Analysis of approximately 80,000 sperm from eight B6C3F1 mice revealed an average baseline frequency of 2.5 per 10,000 sperm carrying partial duplications and deletions of chromosome 2. Extrapolated to the entire haploid genome, approximately 0.4% of mouse sperm are estimated to carry structural chromosomal aberrations, which is more than fivefold lower than the spontaneous frequencies of sperm with chromosome structural aberrations in man. We validated the CT8 assay by comparing the frequencies of abnormal segregants in sperm of T(2;14) translocation carriers detected by this assay against those detected by chromosome painting cytogenetic analysis of meiosis II spermatocytes. The CT8 sperm FISH assay is a promising method for detecting structural chromosome aberrations in mouse sperm with widespread applications in genetics, physiology, and genetic toxicology.

Animals↗
PubMed1997

In vitro assessment of asbestos fibers genotoxicity.

This study was carried out in order to assess the genotoxic effect of in vitro exposure to commercial chrysotile asbestos. V 79 cell line, known as a well-established cellular model, was used for detection of asbestos genotoxic potency. Conventional structural chromosomal aberration analysis and sister chromatid exchange (SCE) method were both used for asbestos genotoxicity assessment. Within the experimental protocol applied, V 79 cells were treated with asbestos in concentrations of 100 and 200 micrograms/ml F-10 (HAM) media during 90 days, respectively. Analysis of changes in chromosome structure as well as of cell ploidy was performed each tenth day of the experimental course, consecutively. Two hundred well spread metaphases were taken into account for chromosomal aberration analysis. Frequency of sister chromatid exchanges was observed in 50 cells per sample. The results of cytogenetic tests revealed structural chromosomal damages, SCE-elevation and changes in cell ploidy. Cytogenetic effect of asbestos obviously depended on the dose applied and on the period of incubation. The results of this study suggest that significant cytogenetic changes occurring after asbestos treatment might directly or indirectly be the part of the biological events responsible for eliciting asbestos-induced carcinogenesis.

Animals↗
PubMed2000

Higher-order structure of interphase chromosomes and radiation-induced chromosomal exchange aberrations.

PURPOSE: To discuss the effects of chromosome structure on the inter- and intrachromosomal exchanges in the framework of the model, which argues that the higher-order chromosome structure contains 10-30 Mbp loop clusters (micelles). RESULTS AND CONCLUSIONS: Intermicelle contacts determine exchange-type chromosome aberrations. Ratios of inter- to intrachromosomal exchanges calculated in the model are similar to the experimental data (literature) for human lymphocytes and flat fibroblasts. The frequency of interchanges is affected by nuclear shape; this might explain the greater number of interchanges observed in 3-D spherical lymphocytes vs. that in 2-D flat fibroblasts. Chromosome configuration (linear vs. folded Rab1) affects the pattern of micelle contacts. The model predicts that chromosomes in haploid Tradescantia microspores have the folded Rab1 orientation; this explains quantitatively the low value of the ratio of dicentrics to centric rings observed in these cells.

Chromosome Aberrations↗
PubMed2004

Detection of structural and numerical chromosomal abnormalities by ACM-FISH analysis in sperm of oligozoospermic infertility patients.

BACKGROUND: Modern reproductive technologies are enabling the treatment of infertile men with severe disturbances of spermatogenesis. The possibility of elevated frequencies of genetically and chromosomally defective sperm has become an issue of concern with the increased usage of ICSI, which can enable men with severely impaired sperm production to father children. Several papers have been published reporting aneuploidy in oligozoospermic patients, but relatively little is known about chromosome structural aberrations in the sperm of these patients. METHODS: We examined sperm from infertile, oligozoospermic individuals for structural and numerical chromosomal abnormalities using a multicolour ACM fluorescence in situ hybridization (FISH) assay that utilizes DNA probes specific for three regions of chromosome 1 to detect human sperm that carry numerical chromosomal abnormalities plus two categories of structural aberrations: duplications and deletions of 1pter and 1cen, and chromosomal breaks within the 1cen-1q12 region. RESULTS: There was a significant increase in the average frequencies of sperm with duplications and deletions in the infertility patients compared with the healthy concurrent controls. There was also a significantly elevated level of breaks within the 1cen-1q12 region. There was no evidence for an increase in chromosome 1 disomy, or in diploidy. CONCLUSIONS: Our data reveal that oligozoospermia is associated with chromosomal structural abnormalities, suggesting that oligozoospermic men carry a higher burden of transmissible, chromosome damage. The findings raise the possibility of elevated levels of transmissible chromosomal defects following ICSI treatment.

Adult↗
PubMed1998

Chromosome studies in first polar bodies from hamster and human oocytes.

Most studies on preconception diagnosis published so far have used polymerase chain reaction (PCR) analysis to identify single gene defects. Although fluorescent DNA probes have been used to obtain a partial cytogenetic diagnosis of aneuploidies in first polar bodies without defined chromosome structures, the analysis of structural chromosome anomalies in the interphase nucleus is not adequate. We describe a procedure to obtain first polar body chromosome complements from hamster and human oocytes. In 63.6% (105 of 165) of hamster first polar bodies the chromosome complement showed a defined chromosome morphology and in 94.1% (16 of 17) of human oocytes fixed after follicular puncture it was possible to obtain high quality, well spread chromosome complements. First polar body chromosomes are fuzzy and shorter than oocyte chromosomes, but fluorescent in-situ hybridization results obtained in human first polar bodies clearly show that it is possible to detect whole chromosomes, centromeres and unique sequences, including the terminal regions of small chromosomes. This suggests that in fresh oocytes, DNA loss resulting from apoptotic chromosome fragmentation has not yet occurred. Using the procedure described, first polar bodies could be used to analyse the meiotic segregation of maternal structural abnormalities and to detect numerical chromosome anomalies in humans.

Aneuploidy↗
PubMed2004

DNA damage processing and aberration formation in plants.

Various types of DNA damage, induced by endo- and exogenous genotoxic impacts, may become processed into structural chromosome changes such as sister chromatid exchanges (SCEs) and chromosomal aberrations. Chromosomal aberrations occur preferentially within heterochromatic regions composed mainly of repetitive sequences. Most of the preclastogenic damage is correctly repaired by different repair mechanisms. For instance, after N-methyl-N-nitrosourea treatment one SCE is formed per >40,000 and one chromatid-type aberration per approximately 25 million primarily induced O6-methylguanine residues in Vicia faba. Double-strand breaks (DSBs) apparently represent the critical lesions for the generation of chromosome structural changes by erroneous reciprocal recombination repair. Usually two DSBs have to interact in cis or trans to form a chromosomal aberration. Indirect evidence is at hand for plants indicating that chromatid-type aberrations mediated by S phase-dependent mutagens are generated by post-replication (mis)repair of DSBs resulting from (rare) interference of repair and replication processes at the sites of lesions, mainly within repetitive sequences of heterochromatic regions. The proportion of DSBs yielding structural changes via misrepair has still to be established when DSBs, induced at predetermined positions, can be quantified and related to the number of SCEs and chromosomal aberrations that appear at these loci after DSB induction. Recording the degree of association of homologous chromosome territories (by chromosome painting) and of punctual homologous pairing frequency along these territories during and after mutagen treatment of wild-type versus hyperrecombination mutants of Arabidopsis thaliana, it will be elucidated as to what extent the interphase arrangement of chromosome territories becomes modified by critical lesions and contributes to homologous reciprocal recombination. This paper reviews the state of the art with respect to DNA damage processing in the course of aberration formation and the interphase arrangement of homologous chromosome territories as a structural prerequisite for homologous rearrangements in plants.

Arabidopsis↗
PubMedDate not supplied

Cytogenetic observations after meglumine antimoniate therapy for visceral leishmaniasis.

Few data are available concerning the genotoxic effects of antimonial salts therapy in humans. A patient suffering from visceral leishmaniasis was treated for 15 days with a cumulative dose meglumine antimoniate 42.5 g. Peripheral blood lymphocytes sampled before treatment, 7 days later, and at the end of therapy (day 15) were examined for the presence of structural chromosome aberrations, sister chromatid exchanges (SCEs), and micronuclei in binucleated cells. The treatment resulted in an increase of binucleated cells carrying micronuclei, with no changes in chromosome structural aberrations or in mean SCE frequency. On the basis of these observations and of experimental results reported in the literature, we conclude that therapy with meglumine antimoniate apparently does not represent a mutagenic or carcinogenic risk to humans.

Animals↗
PubMed1996

Genomic instability in MycER-activated Rat1A-MycER cells.

The deregulated expression of c-Myc protein is associated with the non-random locus-specific amplification of the dihydrofolate reductase (DHFR) gene. This study was performed to determine whether additional chromosomal aberrations occur when c-Myc protein levels are up-regulated for prolonged periods. To this end, we have used Rat1A-MycER cells, which allow the experimental regulation of Myc protein levels. We examined the genomic stability of Rat1A-MycER cells cultivated in either the absence or the presence of estrogen, which reportedly activates the chimeric MycER protein in these cells. Following prolonged periods of MycER activation, Rat1A-Mycer cells exhibited irreversible chromosomal aberrations. The aberrations included numerical changes, chromosome breakage, the formation of circular chromosomal structures, chromosome fusions, and extrachromosomal elements.

Animals↗
PubMed2026

Chromosome painting in plants: history and future perspectives.

Chromosome painting was developed in mammalian species nearly four decades ago and rapidly became a powerful tool for chromosome identification, comparative cytogenetics, and evolutionary genome analysis. Comparative chromosome painting among diverse mammals generated much of the foundational knowledge of chromosome structure, chromosomal rearrangements, and karyotype evolution before the advent of whole-genome sequencing. Although chromosome painting was first demonstrated in plants in 2001, its applications remained largely restricted to a few plant lineages until the development of oligonucleotide (oligo)-based chromosome painting in 2015. During the last decade, oligo-based chromosome painting has transformed plant cytogenetics, enabling many investigations that were previously impossible. These studies have provided new insights into meiotic chromosome pairing, crossover formation, chromosome fusion, karyotype stability, and chromosome evolution across diverse plant lineages. This review summarizes the history of technological development of chromosome painting in plants, highlights major discoveries enabled by oligo-based chromosome painting, and discusses future opportunities, particularly the integration of chromosome painting with three-dimensional chromosome and genome biology.

Chromosome Painting↗
PubMed1982

Similar dose-related chromosome non-disjunction in young and old female mice after X-irradiation.

Radiation-induced chromosome non-disjunction has been investigated in young and old female mice. Chromosome numbers were screened in maternal and paternal pronuclei of 1-cell embryos. To avoid bias due to preparatory artefacts, only the numbers of hyperploid pronuclei were used as measures of chromosome non-disjunction. Spontaneous non-disjunction occurred more frequently in oocytes of old females (1.54%) compared to young females (0.19%). After X-irradiation, both young and old females displayed significant linear increases in non-disjunction with absorbed dose. The slopes of the regressions did not differ significantly. Maternal pronuclei of 1-cell embryos recovered from irradiated females occasionally contained chromosome structural aberrations. The numbers of aberrations showed significant linear relationships to absorbed dose in young and old females. No significant difference was present between the numbers of aberrations in young and old females. Analyses of numerical and structural chromosome anomalies have demonstrated, therefore, no increase in sensitivity to radiation to occur with maternal age.

Aging↗