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Ring chromosome

About: Ring chromosome is a research topic. Over the lifetime, 1546 publications have been published within this topic receiving 31061 citations. The topic is also known as: supernumerary circular chromosome.


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Journal ArticleDOI
TL;DR: This is the first report of r( 9) analyzed by WGS to delineate the mechanism of ring chromosome formation from repairing of subtelomeric DSBs, which resulted in the formation of this r(9) with distal deletions and an interstitial duplication.
Abstract: Constitutional ring chromosome 9, r(9), is a rare chromosomal disorder. Cytogenomic analyses by karyotyping, array comparative genomic hybridization (aCGH) and whole genome sequencing (WGS) were performed in a patient of r(9). Karyotyping detected a mosaic pattern of r(9) and monosomy 9 in 83% and 17% of cells, respectively. aCGH detected subtelomeric deletions of 407 kb at 9p24.3 and 884 kb at 9q34.3 and an interstitial duplication of 5.879 Mb at 9q33.2q34.11. WGS revealed double strand breaks (DSBs) at ends of 9p24.3 and 9q34.3, inverted repeats at ends of subtelomeric and 9q33.2q34.11 regions, and microhomology sequences at the junctions of this r(9). This is the first report of r(9) analyzed by WGS to delineate the mechanism of ring chromosome formation from repairing of subtelomeric DSBs. The loss of telomeres by subtelomeric DSBs triggered inverted repeats induced intra-strand foldback and then microhomology mediated synthesis and ligation, which resulted in the formation of this r(9) with distal deletions and an interstitial duplication. Review of literature found seven patients of r(9) with clinical and cytogenomic findings. These patients and the present patient were registered into the Human Ring Chromosome Registry and a map correlating critical regions and candidate genes with relevant phenotypes was constructed. Variable phenotypes of r(9) patients could be explained by critical regions and genes of DOCK8, DMRT, SMARCA2, CD274, IL33, PTPRD, CER1, FREM1 for 9p deletions, and the EHMT1 gene for 9q34 deletion syndrome. This interactive registry of r(9) could provide information for cytogenomic diagnosis, genetics counseling and clinical management.

8 citations

Journal ArticleDOI
TL;DR: The novel continuous cell line WT-Pe.1 was established in vitro from Wilms tumor with histological features of diffuse anaplasia with numerous abnormalities including ring chromosomes, double-minutes, homogeneous staining regions, radial structures, dicentrics, and several marker chromosomes.

8 citations

Journal ArticleDOI
TL;DR: Ring Chromosome 14 Mosaicism: An Unusual Case Associated with Developmental Delay and Epilepsy, Characterized by Genome Array-CGH is described.
Abstract: Ring Chromosome 14 Mosaicism: An Unusual Case Associated With Developmental Delay and Epilepsy, Characterized by Genome Array-CGH Anna Lisa Nucaro,* Melania Falchi, Tiziana Pisano, Rossano Rossino, Francesca Boscarelli, Giusi Stoico, Angela Milia, Caterina Montaldo, Carlo Cianchetti, and Dario Pruna INN-CNR, Cittadella Universitaria, Monserrato, Cagliari, Italy Clinica di Neuropsichiatria Infantile, Azienda Ospedaliero-Universitaria, Cagliari, Italy Dipartimento di Scienze Pediatriche e Medicina Clinica, Azienda Ospedaliero-Universitaria, Cagliari, Italy Dipartimento di Scienze Chirurgiche e Odontostomatologiche, Universit a di Cagliari, Cagliari, Italy Technogenetics Bouty, Company, Sesto San Giovanni, Italy Dipartimento di Biologia Sperimentale, Universit a di Cagliari, Cagliari, Italy

8 citations

Journal ArticleDOI
TL;DR: Image cytometric measurements demonstrated a dose-dependent effect of aflatoxin B2 (AFB2) treatments on the components of mitotic cell cycle in Vicia faba L. root meristematic cells, indicating that this toxin acts as an inhibitor of cell cycle progression at the G1 transition point.
Abstract: Image cytometric measurements demonstrated a dose-dependent effect of aflatoxin B2 (AFB2) treatments on the components of mitotic cell cycle in Vicia faba L. root meristematic cells. The most evident effect appears to be the accumulation of cells in the G0/G1 phase at the expense of other phases of the cycle (S phase, G2 phase, M phase). These results indicate that this toxin acts as an inhibitor of cell cycle progression at the G1 transition point. In addition, a dose-dependent increase in a fraction of cells having 4C DNA results from the AFB2 treatments. The inhibition of mitotic activity induced by AFB2 treatments is associated with a reduction in seedling growth. Cytological examination of dividing cells revealed an abundance of dose-dependent chromosome abnormalities produced by the applied treatments of AFB2. Chromosomal abnormalities associated with stickiness of chromosomes or due to an action on the mitotic apparatus are the dominant abnormalities induced by this toxin. Some of these abnormalities, particularly chromosome lagging and multipolar ana-telophase configurations, may account for the formation of cells with 4C DNA value. However, true clastogenic chromosomal aberrations including chromosome breaks and ring chromosomes at metaphase and chromosomal bridges at ana-telophase were scored in substantial proportion of cells. The induction of whole chromosome breaks at metaphase is congruent with the indication by the cytometric measurements that AFB2 acts on the G, transition point. The capacity of this toxin to induce clastogenic aberrations may be regarded as an indication of its genotoxic potential. This is also indicated by the formation of micronuclei in interphase cells.

8 citations

Journal ArticleDOI
TL;DR: The present cytological evidence for parasynapsis in Oenothera is not regarded as satisfactory, although if parasynapis occurred it would afford a basis for much at least of the chromosome ring formation in Oensothera.
Abstract: The term mutation should be used in a generic sense to include inherited changes of any kind in the germplasm. Various types of mutations, such as trisomics, polyploids, translocations and gene mutations, can then be classified. The remarkable constancy in the structural arrangement and spatial relationships of the elements making up the germinal material under normal conditions is emphasized. The term catenation is proposed for the linkage of chromosomes in a ring or chain, now known to occur in a number of plants. The causes of catenation, especially in Oenothera, are discussed, and the theory of hybridization combined with some translocations between non-homologous chromosomes is supported. The present cytological evidence for parasynapsis in Oenothera is not regarded as satisfactory, although if parasynapsis occurred it would afford a basis for much at least of the chromosome ring formation in Oenothera.

8 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202310
202221
202123
202019
201919
201836