Analysis of proximal X chromosome pairing in early female mouse meiosis.
The initiation and progression of homologous chromosome pairing at meiosis were investigated in female mice. The proximal end of the X chromosome was identified in fetal oocytes using fluorescence in situ hybridisation with the repeat copy probe 70-38. The X centromeres appeared to be randomly positioned in the nuclei from pre-meiotic interphase to leptotene. The observations indicated no pre-synaptic association for the proximal end of the X chromosome. There was a significant increase in the number of paired X centromeres from mid-zygotene to late zygotene. The proximal end of the X chromosome is therefore a generally late pairing region with no significant association seen before mid-zygotene. The centromeric heterochromatin of all chromosomes could be seen to associate into varying numbers of clusters during pre-leptotene through to pachytene. These clusters do not seem to be directly involved in bringing homologues together, as X centromeres did not consistently localise to the same cluster.
O'Keeffe
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Mammalian Genetics Unit, Medical Research Council, Harwell, Didcot, Oxon OX11 0RD, UK.
Hultén
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Tease
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D000818:Animals; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D005865:Gestational Age; D007038:Hypotonic Solutions / Q000494:pharmacology; D008297:Male; D008540:Meiosis; D051379:Mice; D008809:Mice, Inbred C3H; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D011418:Prophase / Q000235:genetics; D014960:X Chromosome
D007038:Hypotonic Solutions