Mitochondrial Factors Associated with Pollen Development

菜豆（Phaseolus vulgaris）的线粒体发生突变，导致雄性不育。突变是显性的，非致死性的，可以被核基因组抑制因子抑制。一种名为pvsORF239的线粒体不育相关蛋白仅存在于花粉壁上的雄性不育植物的生殖组织中。它似乎是翻译后调控的。通过在这种蛋白质中发现的特定特征，它被主动地从线粒体运输到发育中的花粉的胼胝质层的可能性将通过遗传方法进行研究。其他需要研究的方面是线粒体蛋白酶在营养组织线粒体中蛋白质的快速周转中的可能参与，以及核抑制因子的功能，如果有的话，在蛋白质的运输或周转中。为了在更容易处理的生物体中研究这些问题，该系统将被引入酵母中进行进一步研究。通过对普通豆细胞质雄性不育系统的研究，我们将进一步了解线粒体输出机制、植物线粒体基因表达的组织特异性调控以及线粒体诱导表型核抑制的分子基础。

Mackenzie 9630252 A mutation in the mitochondra of the common bean, Phaseolus vulgaris, results in male sterility. The mutation is dominant, non-lethal and can be suppressed by nuclear genome suppressors. A mitochondrial sterility-associated protein, designated pvsORF239, is found only in reproductive tissues of the male-sterile plant localized to the pollen wall. It appears to be posttranslationally regulated. The possibility that, by virtue of specific characteristics found in this protein, it is actively transported from the mitochondrion to the callose layer of the developing pollen will be investigated by genetic methodology. Other aspects to be investigated are the possible involvement of a mitochondrial protease in the rapid turnover of the protein in the mitochondria of vegetative tissues and the function of nuclear suppressors, if any, in either the transport or turnover of the protein. In order to pursue these questions in a more tractable organism, the system will be introduced into yeast for further study. %%% This investigation of the cytoplasmic male sterility system in common bean will give added insight into our limited understanding of mitochondrial export mechanisms, the tissue-specific regulation of plant mitochondrial gene expression and the molecular basis of nuclear suppression of a mitochondrially-induced phenotype.