A novel gene controlling homothallic life cycle was identified in the yeast Kazachstania naganishii isolated in Japan. This gene was isolated by means of complementing a mutation, mti1, which had led to heterothallism from original homothallism in the yeast. The configuration of original mutation in MTI1 gene revealed that a truncated product is formed due to occurrence of a stop codon by a nucleotide insertion. When the gene was disrupted with a marker, the disruptant spore clone was haploid and stably heterothallic. Disfunction of the gene caused inability to self‐diploidize due to defect of mating‐type interconversion. The gene MTI1 (for Mating Type Interconversion) is a weak homolog of the Saccharomyces cerevisiae VID22/ENV11, which has been reported to function in vacuolar protein processing. K. naganishii has a gene representing significant homology with the HO gene of S. cerevisiae on chromosome V, which has not been clarified to be involved in regulation of life cycle in K. naganishii. The MTI1 gene defined in this study is located on K. naganishii chromosome IV and does not represent significant homology to the above ScHO‐like gene and any other genes concerning life cycles of yeasts. From the viewpoint of gene evolution, it is extremely interesting that the MTI1 gene is a new type of gene controlling homothallism in addition to an HO‐type gene, leading to discovery of an unknown mechanism regulating life cycles in yeasts.

中文翻译：

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在日本分离的酵母 Kazachstania naganishii 中控制同源性的新基因的鉴定

在日本分离的酵母Kazachstania naganishii 中发现了一种控制同种生命周期的新基因。该基因是通过补充突变mti1 来分离的，mti1导致酵母中原始同源性的异源性。MTI1基因中原始突变的构型表明，由于核苷酸插入导致终止密码子的出现，形成了截短的产物。当基因被标记破坏时，破坏孢子克隆是单倍体和稳定的异源。由于交配型互变缺陷，该基因的功能障碍导致无法自二倍体化。基因MTI1接口（用于中号阿婷牛逼YPE我相互转化）是酿酒酵母 VID22 / ENV11的弱同源物，据报道其在液泡蛋白质加工中起作用。克。naganishii具有与S的HO基因具有显着同源性的基因。染色体 V 上的酿酒酵母，尚未阐明其参与K生命周期的调节。长西。本研究中定义的MTI1基因位于K 上。naganishii染色体 IV 并且不代表与上述ScHO 的显着同源性-like 基因和任何其他与酵母生命周期相关的基因。从基因进化的角度来看，非常有趣的是，MTI1基因是除HO型基因之外的一种新型控制同源性的基因，导致发现了调节酵母生命周期的未知机制。