CHLOROPLAST GENE-EXPRESSION IN NUCLEAR, PHOTOSYNTHETIC MUTANTS OF MAIZE
CHLOROPLAST GENE-EXPRESSION IN NUCLEAR, PHOTOSYNTHETIC MUTANTS OF MAIZE
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DOI：
10.1002/j.1460-2075.1986.tb04378.x
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发表时间：
1986-07-01
期刊：
影响因子：
11.4
通讯作者：
TAYLOR, WC
中科院分区：
文献类型：
--
作者：
BARKAN, A;MILES, D;TAYLOR, WC
为了评估核基因在叶绿体生物发生中的可能作用，对5个玉米核病光合作用突变体的叶绿体蛋白和叶绿体RNA进行了鉴定。每个突变体都缺乏一组特有的多肽。免疫印迹分析的高灵敏度和高分辨率表明，在任何情况下多肽都不是完全缺失的。缺乏细胞色素f/b6或光系统I复合体的突变体表现出这些复合体的所有核心亚单位的配位减少，从而保持正确的化学计量比。在Northern blots上分析了编码大多数受影响的叶绿体编码蛋白的RNA转录本。一般来说，突变幼苗中的叶绿体RNA在大小或丰度上没有改变，即使相应的蛋白质是大麦可以检测到的。因此，在大多数情况下，核损伤在转录后水平上作用于叶绿体内，以阻止叶绿体编码多肽的表达。一种名为hcf-38的突变体确实显示出许多叶绿体转录本的丰度和大小发生了惊人的变化。因此，HCF-38基因座可能编码一种在叶绿体转录或RNA加工中起作用的产物。
To assess possible roles of nuclear genes in chloroplast biogenesis, five photosynthetic mutants of maize with nuclear lesions were characterized with respect to their chloroplast proteins and chloroplast RNAs. Each mutant is deficient in a characteristic set of polypeptides. The high sensitivity and resolution of immunoblot analysis revealed that in no case are polypeptides completely missing. Mutants deficient in the cytochrome f/b6 or photosystem I complex show a coordinate reduction of all of the core subunits of these complexes such that the correct stoichiometries are maintained. RNA transcripts encoding most of the affected plastid-encoded proteins were analyzed on Northern blots. In general, chloroplast RNAs in mutant seedlings were not altered in size or abundance, even when the corresponding protein was barley detectable. Therefore, in most cases the nuclear lesions act within the chloroplast at a post-transcriptional level to prevent expression of chloroplast-encoded polypeptides. One mutant, hcf-38, does show striking alterations in the abundance and size of many chloroplast transcripts. The hcf-38 locus might therefore encode a product that functions in chloroplast transcription or RNA processing.