Expression of nuclear genes for chloroplast ribosomal proteins.

我确定了两个基因编码的叶绿体核糖体蛋白L12编码的核基因组中的水稻（水稻）。这些基因被命名为rpl 12 -1和rpl 12 -2（rpl 12，核糖体蛋白L12）。用特异性探针进行的北方分析表明，这两个基因都被转录。每个基因的表达似乎有不同的调节机制。还表明rpl 12 -1的表达以器官特异性方式控制。在单子叶植物和双子叶植物中，成熟肽部分的推导氨基酸序列比转运肽部分的保守。利用已报道的植物rpl 12 s转运肽区的核苷酸序列构建了系统发育树。这棵树包括了在进化过程中何时获得转运肽以及何时复制基因的估计。根据我们的假设，核转位的叶绿体核糖体蛋白L12基因在单子叶植物和双子叶植物分化后获得转运肽，然后在单子叶植物和双子叶植物中独立发生基因复制，然后水稻和黑麦分支分开。为了确定该基因产物的亚细胞定位，我们将其N端区域与绿色荧光蛋白（GFP）融合，并在水稻幼苗中瞬时表达。仅在叶绿体中检测到局部荧光，表明该核基因编码叶绿体核糖体蛋白S9。水稻RPS 9的N端区域与水稻叶绿体核糖体蛋白L12的转运肽区域具有很高的序列相似性，表明这些转运肽具有共同的谱系。

I identified two genes coding for chloroplast ribosomal protein L12 encoded in the nuclear genome of rice (Oryza sativa). The genes were designated rpl12-1 and rpl12-2 (rpl12, ribosomal protein L12). Northern analysis with specific probes revealed that both genes are transcribed. The expression of each gene seems to have different regulation machinery. It is also suggested that the expression of rpl12-1 is controlled in an organ-specific manner. The deduced amino acid sequences of the mature peptide parts are more conserved than those of the transit peptide parts in both monocotyledonous and dicotyledonous plants. A phylogenetic tree was constructed using the nucleotide sequences of the transit peptide region of reported plant rpl12s. The tree includes estimates of when the transit peptides were acquired and when the genes were duplicated in the course of evolution. According to our hypothesis, the nuclear-translocated chloroplast ribosomal protein L12 gene obtained its transit peptide after the divergence of monocots and dicots, then gene duplications occurred independently in monocots and dicots, and then rice and rye branched apart.I have cloned a novel nuclear gene for a ribosomal protein of rice and Arabidopsis that is like the bacterial ribosomal protein S9 (RPS9). To determine the subcellular localization of the gene product, we fused the N-terminal region and green fluorescent protein (GFP), and expressed it transiently in rice seedlings. Localized fluorescence was detectable only in chloroplasts, indicating this nuclear gene encodes chloroplast ribosomal protein S9. The N-terminal region of rice RPS9 was found to have a high sequence similarity to the transit peptide region of the rice chloroplast ribosomal protein L12, suggesting that these transit peptides have a common lineage.