Dynamics of packaging and division of the yeast mitochondrial nuclei.

对酵母线粒体核(mt-核)的包装和分裂机制进行了形态和生化研究。研究了酿酒酵母从厌氧培养向好氧培养转变过程中mt核的动态变化。在培养的过渡过程中，mt核在6h内从巨大的聚集体转变为小颗粒。在本研究中，我们测定了单个巨大mt核和小mt核的DNA含量。接下来，我们发现在厌氧生长的细胞中，在巨大的mt核中几乎没有检测到两种mt核蛋白，但在向有氧条件转移的过程中，这两种蛋白都出现在小mt核中。在免疫荧光显微镜下，我们发现线粒体的动态形态变化与mt核的变化是平行的，细胞质中的肌动蛋白斑块也由聚集的形式转变为小斑块，以响应th…。更多的有氧条件。研究了蛋白质组分在mt-核包装中的作用，得到了以下结果。我们鉴定了一种新的mt-核蛋白，命名为Mnp1p。该蛋白是一种22 kDa的酸性蛋白，与大肠杆菌核糖体蛋白L7/L12有同源性。为了从进化的角度考察mt-核蛋白的多样性，我们从酵母近缘念珠菌中分离出mt-核，并鉴定了几种mt-核蛋白。此外，我们还纯化了一种新的30 kDa DNA结合蛋白，推测为Abf2p同源物。我们还成功地从毕赤酵母中纯化了一个26 kDa的类Abf2p蛋白。比较了野生型细胞和Abf2p缺陷细胞的mt核对核酸酶的敏感性。我们发现，来自Abf2p缺陷细胞的mt核比来自野生型细胞的mt核更耐微球菌核酸酶消化。在研究过程中，我们证明了与mt-核相关的一个主要核酸酶是Nuc1p核酸酶。包装到mt-核中的mtDNA被微球菌核酸酶均匀消化，而不是间断消化。较少

Morphological and biochemical approaches were performed on the mechanisms of packaging and division of yeast mitochondrial nuclei (mt-nuclei).1. Dynamic changes in mt-nuclei during the transition from anaerobic to aerobic culture were investigated in the yeast Saccharomyces cerevisiae. During transition of the culture, the mt-nuclei changes their morphology from giant aggregates to small particles within 6 h. In the present study, we determined DNA content of individual giant mt-nuclei and small mt-nuclei. Next, we found that two species of mt-nuclei proteins were hardly detected in giant mt-nuclei in anaerobically-grown cells, but both proteins appeared in the small mt-nuclei during transfer to aerobic conditions. Using immnofluorescence microscopy, we demonstrated that the dynamic morphological changes in mitochondria occur parallel to the changes of the mt-nuclei and that the actin patches in the cytoplasm also changes from the aggregated forms to the small patches in response to th … More e aerobic conditions.2. Roles of protein components on packaging of the mt-nuclei were investigated, and following results were obtained.We identified a novel mt-nuclei protein named as Mnp1p. This protein was a 22-kDa acidic protein and had a homology with E. coli ribosomal protein, L7/L12. In order to examine the diversity of the mt-nuclei proteins from evolutionary aspects, we isolated the mt-nuclei from the yeast Candida parapsilosis and identified several mt-nuclei proteins. Furthermore, we purified a novel 30-kDa DNA-binding protein, a putative Abf2p homolog. We also successfully purified a 26-kDa Abf2p-like protein from the yeast Pichia jadinii.3. Nuclease sensitivity of the mt-nuclei was compared between mt-nuclei from wild-type cells and Abf2p-deficient cells. We found that the mt-nuclei from Abf2p-deficient cells were more resistant to micrococcal nuclease digestion than the mt-nuclei from wild type cells. During the course of study, we demonstrated that a major nuclease associated with mt-nuclei is a Nuc1p nuclease. MtDNA that is packaged into the mt-nuclei was digested uniformly rather than discontinuously with micrococcal nuclease. Less