[果蝇卵母细胞中染色中心的结构、同源配对的起始及交叉形成的调控]

[The structure of the chromocenter in the oocytes, the initiation of homologous pairing and the regulation of the formation of crossing over in Drosophila].

作者信息

Chubykin V L

出版信息

Tsitologiia. 1995;37(5-6):481-90.

Abstract

The structure of chromocenter and pairing of homologs in Drosophila oocytes with different X-chromosome inversions (sc7, sc9, BM1, y4, sc4sc8), and acrocentric compound C(1)DX were studied. Disturbances of chromosome pairing in compound C(1)DX, inversion of heterozygotes and some homozygotes (BM1, sc4sc8) were observed. Besides, disturbances of precentromeric heterochromatin regions pairing and nonassociation of X-bivalents with chromocenter were observed. It turned out that inversion loops were formed only in chromocenter formation peculiarities. It is supposed that disturbance of homologous pairing in inversion homozygotes is associated with transference of sites initiating the homologous pairing. These sites are in pretelomeric and adjacent heterochromatin regions. Interchromosomal effects of chromosome aberrations on crossingover and, probably, modification of its frequency by other factors are associated with the state of precentrometic heterochromatin homologous pairing in chromocenter. The formation of crossover exchanges is completed with a total pairing in these chromosome regions and subsequently with reorganization of the meiotic chromosome structure.

摘要

研究了果蝇卵母细胞中具有不同X染色体倒位（sc7、sc9、BM1、y4、sc4sc8）以及近端着丝粒复合染色体C(1)DX的染色中心结构和同源染色体配对情况。观察到复合染色体C(1)DX、杂合子和一些纯合子（BM1、sc4sc8）的染色体配对紊乱。此外，还观察到着丝粒前异染色质区域配对紊乱以及X二价体与染色中心不关联。结果表明，倒位环仅在染色中心形成特性中形成。据推测，倒位纯合子中同源配对的紊乱与启动同源配对的位点转移有关。这些位点位于端粒前和相邻的异染色质区域。染色体畸变对交换的染色体间效应以及可能由其他因素对其频率的改变与染色中心着丝粒前异染色质同源配对状态有关。交换交换的形成在这些染色体区域完全配对后完成，随后伴随着减数分裂染色体结构的重组。