Funtionelle Charakterisierung von mTERF-homologen mitochondriellen Proteinen in pflanzlichen Systemen am Beispiel des kernkodierten Faktors MOC1 aus C. reinhardtii

线粒体在细胞代谢中起着至关重要的作用，但迄今为止，关于线粒体基因的表达是如何调节的知识仍然很少。在过去的几年里，主要集中在动物系统的研究工作，导致了进化保守的mTERF（线粒体转录终止因子）蛋白质家族的鉴定。mTERF因子存在于高等和低等真核生物中，并参与线粒体基因表达的不同步骤，从线粒体基因组的复制到线粒体mRNA的翻译。光合生物的测序基因组也包含mTERF基因，但除了一种莱茵衣藻mTERF蛋白外，没有其他植物mTERF的数据。梭reinhardtii蛋白，命名为MOC1，通过随机诱变方法鉴定，并显示为正常光合光适应所必需的。MOC1无效突变体Stm6的检查显示，线粒体基因表达，特别是呼吸电子传递链的编码组分的表达，在光照下异常。在植物细胞中，线粒体参与与叶绿体和细胞核的复杂的细胞器间相互作用，但线粒体基因表达变化背后的分子基础，特别是在光下，还不清楚。该研究项目的目的是充分表征mTERF蛋白在莱茵衣藻中的作用，并将涉及使用突变株stm6。在该项目中，mTERF蛋白干预基因表达的分子机制将得到解决。因此，我希望获得重要的一般性的见解mTERF蛋白在植物系统中的功能。

Mitochondria play a fundamentally important role in cellular metabolism, but as yet there is still very little knowledge about how the expression of mitochondrial genes is regulated. Research efforts over the past few years, mainly concentrated on animal systems, have led to the identification of the evolutionary conserved mTERF (mitochondrial transcription termination factor) protein family. mTERF factors exist in higher and lower eukaryotes and are involved in different steps of mitochondrial gene expression, ranging from replication of the mitochondrial genome to translation of mitochondrial mRNAs. Sequenced genomes of photosynthetic organisms also contain mTERF genes, but apart from one Chlamydomonas reinhardtii mTERF protein no data exist for other plant mTERFs. The C. reinhardtii protein, designated MOC1, was identified by a random mutagenesis approach and shown to be essential for normal photosynthetic light-acclimation. Examination of the MOC1 null mutant, Stm6, revealed that mitochondrial gene expression, and in particular the expression of mitochondria-encoded components of the respiratory electron transport chain, was aberrant in the light. In plant cells, mitochondria are known to participate in complex interorganellar interactions with chloroplasts and the nucleus, but as yet the molecular basis behind changes in mitochondrial gene expression, especially in the light, are unclear. The aim of this research project is to fully characterize the role of mTERF proteins in Chlamydomonas reinhardtii and will involve the use of the mutant strain stm6. Within the project the molecular mechanism by which mTERF proteins intervene in gene expression will be addressed. As a result I expect to gain important genral insights into the function of mTERF proteins in plant systems.