Chromosome

About: Chromosome is a research topic. Over the lifetime, 17538 publications have been published within this topic receiving 660077 citations. The topic is also known as: chromosomes & GO:0005694.

Chromosome painting with human chromosome-specific DNA libraries reveals the extent and distribution of conserved segments in bovine chromosomes

Abstract: Commercially available human chromosome-specific DNA libraries covering the whole karyotype were hybridized to normal bovine metaphase spreads to characterize the conserved chromosomal segments between man and cattle. All chromosome libraries except the Y chromosome library displayed a signal on at least part of one or more bovine chromosomes. The labeling was clearly visualized and permitted precise delineation of the hybridized bovine chromosomal segments. This study indicates that the reorganization of the genetic material between human and bovine genomes is not as great as expected from classical comparative cytogenetics based on banding patterns. However, apart from interchromosomal rearrangements between ancestral forms of human and bovine chromosomes, a majority of intrachromosomal rearrangements must have occurred in these species during evolution to explain the differences in the banding patterns of their chromosomes. These results show that chromosome painting with heterologous chromosome-specific DNA libraries can provide useful information in comparative studies on karyotypes and gene maps of distantly related mammalian species. The observations are discussed in relation to published data on gene mapping in man and cattle.

A Third Wilms' Tumor Locus on Chromosome 16q

Abstract: Loss of heterozygosity studies have been used to identify chromosomal regions which are frequently deleted and thus indicate areas which may harbor tumor suppressor genes. As a result, both the WT1 gene located in chromosome 11p13 and an unidentified gene(s) within chromosome 11p15 have been implicated in Wilms' tumorigenesis. Cytogenetic and linkage studies suggest that additional non-chromosome 11 sites are involved in Wilms' tumor. Because these sites may also involve loss of heterozygosity, loci on 33 autosomal arms were screened for allele loss in a series of Wilms' tumors. We found that in addition to loss on chromosome 11p (11 of 25 informative tumors) there was significant loss on chromosome 16q (9 of 45 informative tumors), while the total frequency of allele loss excluding these loci was low (9 of 426 total informative loci). These data indicate that losses of both chromosome 11p and 16q alleles are nonrandom events and suggest that 16q is the location of a third tumor suppressor gene underlying Wilms' tumorigenesis. The parental origin of the lost chromosome 16q allele was determined in eight sporadic tumors. Alleles of paternal and of maternal origin were each lost in four sporadic tumors indicating that, unlike chromosome 11p, alleles of either parental origin are lost on 16q.

The Drosophila Su(var)2-10 locus regulates chromosome structure and function and encodes a member of the PIAS protein family

Abstract: The conserved heterochromatic location of centromeres in higher eukaryotes suggests that intrinsic properties of heterochromatin are important for chromosome inheritance. Based on this hypothesis, mutations in Drosophila melanogaster that alter heterochromatin-induced gene silencing were tested for effects on chromosome inheritance. Here we describe the characterization of the Su(var)2-10 locus, initially identified as a Suppressor of Position-Effect Variegation. Su(var)2-10 is required for viability, and mutations cause both minichromosome and endogenous chromosome inheritance defects. Mitotic chromosomes are improperly condensed in mutants, and polytene chromosomes are structurally abnormal and disorganized in the nucleus. Su(var)2-10 encodes a member of the PIAS protein family, a group of highly conserved proteins that control diverse functions. SU(VAR)2-10 proteins colocalize with nuclear lamin in interphase, and little to no SU(VAR)2-10 is found on condensed mitotic chromosomes. SU(VAR)2-10 is present at some polytene chromosome telomeres, and FISH analyses in mutant polytene nuclei revealed defects in telomere clustering and telomere–nuclear-lamina associations. We propose that Su(var2-10 controls multiple aspects of chromosome structure and function by establishing/maintaining chromosome organization in interphase nuclei.