Analysis of chloroplast division mechanism by genome information, gene expression profile and reverse genetics.

我利用拟南芥的基因表达谱，选择了120个与ARC3、叶绿体分裂因子FtsZ基因共表达的基因，并从一个库存中心获得了每个基因的T-DNA系。我用PCR方法从种子中筛选了T-DNA插入的同源系。用光学显微镜观察了属系细胞中叶绿体的数量和大小。At1g56050和At1g26230的T-DNA细胞系细胞中存在少量异常大的叶绿体，提示At1g56050和At1g26230是新的叶绿体分裂因子。利用酵母双杂交系统分析了ARC3蛋白与At1g56050或At1g26230的相互作用。结果表明，At1g56050蛋白与ARC3蛋白相互作用。提示At1g56050 （gtp结合蛋白）是新的叶绿体分裂因子。DNA阵列分析显示，野生型和突变体之间的基因表达谱基本相同，但突变体中At5g42825的表达量高于野生型。At5g42825基因没有明确的蛋白编码区，提示At5g42825可能具有天然RNAi的功能。

I selected 120 genes that are co-expressed with ARC3 and FtsZ genes, chloroplast division factor, using a gene expression profile in Arabidopsis thaliana, and I got the T-DNA line of the each gene from a stock center. I screened the homo lines of T-DNA insertion from the seeds by PCR. A number or size of chloroplasts in the homo line cells were observed with an optical microscope. The T-DNA lines of At1g56050 and At1g26230 had a small number of abnormally large chloroplasts in the cells, suggesting that At1g56050 and At1g26230 were the novel chloroplast division factors. The interaction of ARC3 protein and At1g56050 or At1g26230 were analyzed with yeast two-hybrid system. The results indicated that At1g56050 protein interacted with ARC3 protein. It was suggested that At1g56050 (GTP-binding protein) was the novel chloroplast division factor.DNA array analysis revealed that gene expression profile between wild type and arc3 mutant plants was almost same but the expression of At5g42825 in the mutant was higher than that of wild type. At5g42825 gene has no clear protein coding region, suggesting that At5g42825 might have a function as native RNAi.