Heteroduplex DNA formation and homolog pairing in yeast meiotic mutants.
Heteroduplex DNA formation and homolog pairing in yeast meiotic mutants.
复制标题
酵母减数分裂突变体中异源双链 DNA 的形成和同源配对。
DOI：
10.1093/genetics/141.1.75
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发表时间：
1995
期刊：
影响因子：
3.3
通讯作者：
Roeder,GS
中科院分区：
文献类型：
--
作者：
Nag,DK;Scherthan,H;Rockmill,B;Bhargava,J;Roeder,GS
以前对酿酒酵母的研究已经发现了几个减数分裂特异基因，它们的产物是野生型减数分裂重组和正常联会复合体(SC)形成所必需的。对这些突变体中的几个进行了物理检测，以检测减数分裂重组中的异源双链DNA(HDNA)中间体。在rec102、mei4和Hop1突变体中未检测到hDNA；在Red1、MEK1和mer1菌株中观察到hDNA水平降低，在ZIP1中观察到高于野生型水平的hDNA。这些结果表明，在减数分裂重组途径中，REC102、MEI4、HOP1、Red1、MEK1和MER1基因产物在hDNA形成之前起作用，而ZIP1起作用晚。检测hDNA形成的相同突变体通过染色体特异DNA探针的原位杂交来监测减数分裂染色体配对，以扩散减数分裂核。在ZIP1和MEK1突变体中，同源配对发生在野生型水平，但在mei4、rec102、Hop1、Red1和mer1菌株中显著减少。即使是不能重组或不能使任何SC或SC前体发生减数分裂的突变体也会经历大量的减数分裂染色体配对。原位杂交结果显示，Mer1、Red1和Hop1菌株的减数分裂过程中存在染色质凝集缺陷。
Previous studies of Saccharomyces cerevisiae have identified several meiosis-specific genes whose products are required for wild-type levels of meiotic recombination and for normal synaptonemal complex (SC) formation. Several of these mutants were examined in a physical assay designed to detect heteroduplex DNA (hDNA) intermediates in meiotic recombination. hDNA was not detected in the rec102, mei4 and hop1 mutants; it was observed at reduced levels in red1, mek1 and mer1 strains and at greater than the wild-type level in zip1. These results indicate that the REC102, MEI4, HOP1, RED1, MEK1 and MER1 gene products act before hDNA formation in the meiotic recombination pathway, whereas ZIP1 acts later. The same mutants assayed for hDNA formation were monitored for meiotic chromosome pairing by in situ hybridization of chromosome-specific DNA probes to spread meiotic nuclei. Homolog pairing occurs at wild-type levels in the zip1 and mek1 mutants, but is substantially reduced in mei4, rec102, hop1, red1 and mer1 strains. Even mutants that fail to recombine or to make any SC or sc precursors undergo a significant amount of meiotic chromosome pairing. The in situ hybridization procedure revealed defects in meiotic chromatin condensation in mer1, red1 and hop1 strains.