McCormac D J, Barkan A
Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229, USA.
Plant Cell. 1999 Sep;11(9):1709-16. doi: 10.1105/tpc.11.9.1709.
To elucidate mechanisms that regulate chloroplast translation in land plants, we sought nuclear mutations in maize that disrupt the translation of subsets of chloroplast mRNAs. Evidence is presented for a nuclear gene whose function is required for the translation of the chloroplast atpB/E mRNA. A mutation in atp1 results in a failure to accumulate the chloroplast ATP synthase complex due to reduced synthesis of the AtpB subunit. This decrease in AtpB synthesis does not result from a change in atpB mRNA structure or abundance. Instead, the atpB mRNA is associated with abnormally few ribosomes in atp1-1 mutants, indicating that atp1 function is required during translation initiation or early in elongation. Previously, only one nuclear gene that is required for the translation of specific chloroplast mRNAs had been identified in a land plant. Thus, atp1 will be a useful tool for dissecting mechanisms of translational control in chloroplasts.
为阐明调控陆地植物叶绿体翻译的机制，我们在玉米中寻找破坏叶绿体mRNA亚群翻译的核突变。本文提供了证据，证明存在一个对叶绿体atpB/E mRNA翻译起作用的核基因。atp1突变导致叶绿体ATP合酶复合体积累失败，原因是AtpB亚基合成减少。AtpB合成的减少并非源于atpB mRNA结构或丰度的变化。相反，在atp1-1突变体中，atpB mRNA与异常少的核糖体相关联，表明在翻译起始或延伸早期需要atp1发挥功能。此前，在陆地植物中仅鉴定出一个对特定叶绿体mRNA翻译起作用的核基因。因此，atp1将成为剖析叶绿体翻译控制机制的有用工具。
