Cytochemical and molecular peculiarities of heterochromatic regions of bovine chromosomes have been studied, using specific fluorochrome staining induced decondensation, in situ hybridization, pretreatment of restriction enzymes. The heterochromatin of autosomes demonstrated a strong homogeneity. In chromosome Y two small specific heterochromatic regions were found lacking a long repeated tandem block of nucleotides enriched in GC base pairs and having no tandem block of Bkm repeats (10(4) b.p.). This class repeats are probably interspersed in the bovine genome. A rather seldom character of mammalian karyotypes is the absence of cytochemical heterochromatin in the X chromosome.
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Nat Commun
January 2025
Instituto de Biología Funcional y Genómica, Zacarías González 2, Salamanca, 37007, Spain.
Accurate gametogenesis requires the establishment of the telomere bouquet, an evolutionarily conserved, 3D chromosomal arrangement. In this spatial configuration, telomeres temporarily aggregate at the nuclear envelope during meiotic prophase, which facilitates chromosome pairing and recombination. The mechanisms governing the assembly of the telomere bouquet remain largely unexplored, primarily due to the challenges in visualizing and manipulating the bouquet.
View Article and Find Full Text PDFbioRxiv
November 2024
Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
To maintain genome stability, proliferating cells must enact a program of telomere maintenance. While most tumors maintain telomeres through the action of telomerase, a subset of tumors utilize a DNA-templated process termed Alternative Lengthening of Telomeres or ALT. ALT is associated with mutations in the ATRX/DAXX/H3.
View Article and Find Full Text PDFNat Commun
January 2025
Infinity, Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, Inserm U1291, CNRS U5051, Toulouse, France.
Protective immune responses require close interactions between conventional (Tconv) and regulatory T cells (Treg). The extracellular mediators and signaling events that regulate the crosstalk between these CD4 T cell subsets have been extensively characterized. However, how Tconv translate Treg-dependent suppressive signals at the chromatin level remains largely unknown.
View Article and Find Full Text PDFbioRxiv
December 2024
Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
The centromere effect (CE) is a meiotic phenomenon that ensures meiotic crossover suppression in pericentromeric regions. Despite being a critical safeguard against nondisjunction, the mechanisms behind the CE remain unknown. Previous studies have shown that various regions of the pericentromere, encompassing proximal euchromatin, beta and alpha heterochromatin, undergo varying levels of crossover suppression, raising the question of whether distinct mechanisms establish the CE in these different regions.
View Article and Find Full Text PDFEMBO J
January 2025
Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
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