REGULATION OF YEAST MATING-TYPE INTERCONVERSION - FEEDBACK-CONTROL OF HO GENE-EXPRESSION BY THE MATING-TYPE LOCUS
REGULATION OF YEAST MATING-TYPE INTERCONVERSION - FEEDBACK-CONTROL OF HO GENE-EXPRESSION BY THE MATING-TYPE LOCUS
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DOI：
10.1073/pnas.80.10.3035
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发表时间：
1983-01-01
期刊：
影响因子：
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通讯作者：
HERSKOWITZ, I
中科院分区：
文献类型：
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作者：
JENSEN, R;SPRAGUE, GF;HERSKOWITZ, I
酵母交配型相互转化的最终产物是稳定的α/α。二倍体细胞携带HO基因的单倍体细胞在2步过程中产生二倍体细胞：首先，细胞由于HO催化的遗传重排（盒取代）而转换交配类型;然后，相反类型的细胞交配以形成/α。二倍体交配型互变不发生在a/α中。二倍体，尽管存在HO基因。通过筛选酵母克隆库（构建在载体YEp 13中）中允许通过ho细胞进行交配型转换的质粒，鉴定携带HO基因的质粒。负责交配型互变的酵母片段通过同源性整合在HO位点，从而证实其携带HO。使用HO基因作为探针表明，具有活跃的交配型互变系统的菌株产生HO RNA; HO/HO细胞不需要，并且这种抑制需要MATa 1和MATa 2基因的产物。因此，在a/α中不发生配对型相互转换。HO/HO细胞中，因为HO基因产物不合成。交配型基因座在遗传学上被认为是一个调控基因座，它在RNA产生水平上控制着一个非连锁基因（HO）的表达。HO基因处于负反馈控制下：在成功完成二倍化（a/α形成）后，其表达被抑制。二倍体）。
The ultimate product of yeast mating-type interconversion is a stable a/.alpha. diploid cell. A haploid cell carrying the HO gene gives rise to a diploid cell in a 2-step process: first, the cell switches mating type as a result of genetic rearrangement (cassette substitution) catalyzed by HO; then, cells of opposite type mate to form a/.alpha. diploids. Mating-type interconversion does not occur in a/.alpha. diploids despite the presence of the HO gene. A plasmid carrying the HO gene was identified by screening a yeast clone bank (constructed in vector YEp13) for plasmids that allow mating-type switching by ho cells. The yeast segment responsible for mating-type interconversion integrates by homology at the ho locus, thus confirming that it carries HO. Using the HO gene as a probe showed that strains with an active mating-type interconversion system produoce HO RNA; a/.alpha. HO/HO cells do not and that this inhibition requires products of the MATa1 and MATa2 genes. Thus, mating-type interconversion does not occur in a/.alpha. HO/HO cells because the HO gene product is not synthesized. The mating-type locus, proposed on genetic grounds to be a regulatory locus, controls expression of an unlinked gene (HO) at the level of RNA production. The HO gene is under negative feedback control: its expression is inhibited after successful completion of diploidization (formation of a/.alpha. diploids).