Study on the post-transcriptional regulators of cyanobacteria and chloroplasts

1.单细胞蓝藻聚球菌（Synechococcus sp. PCC 6301）含有两个与叶绿体同源的rna结合结构域的蛋白质。这是rna结合蛋白（RNPs）在原核生物中存在的第一个证据，并证实了叶绿体RNPs起源于蓝藻。对烟草和拟南芥叶绿体RNPs编码基因的分析表明，叶绿体RNPs可分为三类。叶绿体RNPs被证明与多种叶绿体mRNA物种、非核糖体16S rRNA和含内含子的前trnas作为稳定的rna -蛋白复合物相关。这一观察结果强烈提示叶绿体RNPs参与RNA加工和RNA稳定性。我们发现了新型的rna结合蛋白。这些新型蛋白含有n端rna结合域和c端甘氨酸富集域，因此被命名为RGP （RNA-binding glycine-rich proteins）。RGP蛋白可能参与细胞核的转录后调控。基于rna结合域结构和核酸结合特性，我们讨论了上述三种rna结合蛋白的进化关系。

1.The unicellular cyanobacterium, Synechococcus sp. PCC 6301 has two proteins containing an RNA-binding domain homologous to the chloroplast counterparts. This is the first evidence of RNA-binding proteins (RNPs) in prokaryotes and confirms that chloroplast RNPs are of cyanobacterial origin.2.Analysis of the genes encoding chloroplast RNPs from tobacco and Arabidopsis thaliana indicated that chloroplast RNPs can be categorized into three groups.3.Chloroplast RNPs were demonstrated to be associated with a variety of chloroplast mRNA species, non-ribosomal 16S rRNA and intron-containing pre-tRNAs as stable RNA-protein complexes. This observation strongly suggests that the chloroplast RNPs are involved in RNA processing and RNA stability.4.We discovered novel types of RNA-binding proteins. These novel proteins contain an N-terminal RNA-binding domain and C-terminal glycine-rich domain, therefore they are named RGP (RNA-binding Glycine-rich Proteins). RGP proteins are possibly involved in post-transcriptional regulation in nucleus.5.Based on the RNA-binding domain structures and nucleic acids-binding properties, we discussed evolutionary relationship of the above three types of RNA-binding proteins.