Processing of the psbA 5' untranslated region in Chlamydomonas reinhardtii depends upon factors mediating ribosome association.
Processing of the psbA 5' untranslated region in Chlamydomonas reinhardtii depends upon factors mediating ribosome association.
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DOI：
10.1083/jcb.143.5.1145
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发表时间：
1998-11-30
期刊：
影响因子：
--
通讯作者：
Mayfield SP
中科院分区：
文献类型：
--
作者：
Bruick RK;Mayfield SP
叶绿体psbAmRNA的5′端非翻译区编码D1蛋白，在莱茵衣藻中被加工。加工发生在共有Shine-Dalgarno序列的上游，并导致从5′端去除54个核苷酸，包括先前鉴定为D1表达的重要结构的茎环元件。在C中检查此处理事件。在叶绿体或核基因组中含有突变的莱茵衣藻菌株阻断psbA翻译，揭示了加工和核糖体结合之间的相关性。psbA mRNA 5′非翻译区内的突变破坏Shine-Dalgarno序列，作为核糖体结合位点，阻止翻译并阻止mRNA加工。类似地，特异性影响D1蛋白合成的核突变特异性影响psbA mRNA的加工。在体外，茎环元件的损失并不禁止绑定的信息特异性蛋白质复合物所需的翻译激活psbA照明。这些结果是一致的叶绿体信息，介导的核编码因子，整合mRNA加工，信息稳定性，核糖体协会和翻译的分级成熟途径。
The 5′ untranslated region of the chloroplast psbA mRNA, encoding the D1 protein, is processed in Chlamydomonas reinhardtii. Processing occurs just upstream of a consensus Shine-Dalgarno sequence and results in the removal of 54 nucleotides from the 5′ terminus, including a stem-loop element identified previously as an important structure for D1 expression. Examination of this processing event in C. reinhardtii strains containing mutations within the chloroplast or nuclear genomes that block psbA translation reveals a correlation between processing and ribosome association. Mutations within the 5′ untranslated region of the psbA mRNA that disrupt the Shine-Dalgarno sequence, acting as a ribosome binding site, preclude translation and prevent mRNA processing. Similarly, nuclear mutations that specifically affect synthesis of the D1 protein specifically affect processing of the psbA mRNA. In vitro, loss of the stem-loop element does not prohibit the binding of a message-specific protein complex required for translational activation of psbA upon illumination. These results are consistent with a hierarchical maturation pathway for chloroplast messages, mediated by nuclear-encoded factors, that integrates mRNA processing, message stability, ribosome association, and translation.