Chloroplast ribosome release factor 1 (AtcpRF1) is essential for chloroplast development
Chloroplast ribosome release factor 1 (AtcpRF1) is essential for chloroplast development
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DOI：
10.1007/s11103-007-9166-7
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发表时间：
2007-07-01
影响因子：
5.1
通讯作者：
Shinozaki, Kazuo
中科院分区：
文献类型：
--
作者：
Motohashi, Reiko;Yamazaki, Takanori;Shinozaki, Kazuo
为了研究参与叶绿体发育的核基因的功能，我们利用激活子/解离（Ac/Ds）转座子标签系统对拟南芥白化和淡绿色突变体进行了系统分析。在这项研究中，我们重点关注其中一个白化突变体，命名为apg3 - 1（代表白化（albino）或淡绿（pale green）突变体3）。一个编码核糖体释放因子1（RF1）同源物的基因因Ds转座子插入APG3基因而被破坏；T - DNA插入同一基因导致了相似的表型（apg3 - 2）。APG3基因（At3g62910）有15个外显子，编码一个含转运肽的422个氨基酸的蛋白质，该转运肽的功能是将蛋白质靶向叶绿体。APG3的氨基酸序列与大肠杆菌的RF1有40.6%的同源性，利用大肠杆菌rf1突变体进行的互补分析表明，APG3在大肠杆菌中作为RF1发挥作用，尽管在大肠杆菌RF2缺陷（rf2）突变体中互补未成功。这些结果表明APG3蛋白是大肠杆菌RF1的直系同源物，对叶绿体翻译机制至关重要；因此它被命名为AtcpRF1。由于apg3 - 1植株的叶绿体几乎没有内部类囊体膜，并且通过免疫印迹分析未检测到与光合作用相关的叶绿体蛋白，所以AtcpRF1被认为对叶绿体发育至关重要。
To study the functions of nuclear genes involved in chloroplast development, we systematically analyzed albino and pale green Arabidopsis thaliana mutants by use of the Activator/Dissociation (Ac/Ds) transposon tagging system. In this study, we focused on one of these albino mutants, designated apg3-1 (for (a) under bar lbino or (p) under bar ale (g) under bar reen mutant (3) under bar). A gene encoding a ribosome release factor 1 (RF1) homologue was disrupted by the insertion of a Ds transposon into the APG3 gene; a T-DNA insertion into the same gene caused a similar phenotype (apg3-2). The APG3 gene (At3g62910) has 15 exons and encodes a protein (422-aa) with a transit peptide that functions in targeting the protein to chloroplasts. The amino acid sequence of APG3 showed 40.6% homology with an RF1 of Escherichia coli, and complementation analysis using the E. coli rf1 mutant revealed that APG3 functions as an RF1 in E. coli, although complementation was not successful in the RF2-deficient (rf2) mutants of E. coli. These results indicate that the APG3 protein is an orthologue of E. coli RF1, and is essential for chloroplast translation machinery; it was accordingly named AtcpRF1. Since the chloroplasts of apg3-1 plants contained few internal thylakoid membranes, and chloroplast proteins related to photosynthesis were not detected by immunoblot analysis, AtcpRF1 is thought to be essential for chloroplast development.