Menees T M, Roeder G S
Department of Biology, Yale University, New Haven, Connecticut 06511-8112.
Genetics. 1989 Dec;123(4):675-82. doi: 10.1093/genetics/123.4.675.
Mutants at the MEI4 locus were detected in a search for mutants defective in meiotic gene conversion. mei4 mutants exhibit decreased sporulation and produce inviable spores. The spore inviability phenotype is rescued by a spo13 mutation, which causes cells to bypass the meiosis I division. The MEI4 gene has been cloned from a yeast genomic library by complementation of the recombination defect and has been mapped to chromosome V near gln3. Strains carrying a deletion/insertion mutation of the MEI4 gene display no meiotically induced gene conversion but normal mitotic conversion frequencies. Both meiotic interchromosomal and intrachromosomal crossing over are completely abolished in mei4 strains. The mei4 mutation is able to rescue the spore-inviability phenotype of spo13 and 52 strains (i.e., mei4 spo13 rad52 mutants produce viable spores), indicating that MEI4 acts before RAD52 in the meiotic recombination pathway.
在寻找减数分裂基因转换缺陷突变体的过程中，检测到了MEI4基因座的突变体。mei4突变体的孢子形成减少，产生不可育的孢子。spo13突变可挽救孢子不可育的表型，spo13突变会使细胞绕过减数分裂I期。通过重组缺陷互补从酵母基因组文库中克隆出了MEI4基因，并将其定位到V号染色体上靠近gln3的位置。携带MEI4基因缺失/插入突变的菌株未表现出减数分裂诱导的基因转换，但有正常的有丝分裂转换频率。在mei4菌株中，减数分裂的染色体间和染色体内交换均被完全消除。mei4突变能够挽救spo13和52菌株的孢子不可育表型（即mei4 spo13 rad52突变体产生可育孢子），这表明MEI4在减数分裂重组途径中作用于RAD52之前。
