Poster: Regulation of gene expression

Abs # 759: Functional study of CIA2 gene by genome-wide Arabidopsis oligo microarray analysis

Presenter:	Sun, Chih-Wen , cwsun@cc.ntnu.edu.tw
Authors	Sun, Chih-Wen  (A)   Kuo, Min-Yan  (B)   Li, Hsou-min  (B)
Affiliations:	(A): Department of Life Science, National Taiwan Normal University (B): Institute of Molecular Biology, Academia Sinica

The biosynthesis and maintenance of chloroplasts reply on the coordination between the expression of nuclear and plastid genomes. However, the former seems to play a more important role in regulating chloroplast development since more than ninety percent of chloroplastic proteins are nuclear-encoded and then post-translationally imported into chloroplasts. We had previously isolated an Arabidopsis mutant, cia2, which was defective in protein import into chloroplasts (Sun, et. al., The Plant Cell, 2001). Further studies revealed that CIA2 gene encoded a transcription factor, and was capable in controlling the gene expression of certain chloroplastic translocon genes. In order to explore more chloroplastic genes whose expressions are regulated by CIA2 in nucleus, we used Agilent 60-mer oligo microarray consisting of 21,500 Arabidopsis gene elements to compare the expression differences between wild-type Arabidopsis (ecotype Col) and mutant. The analyses of the results indicated that the expressions of many nucleus-encoded plastid-specific ribosomal genes were decreased approximately to 2 folds in cia2 mutant. It hence concludes that CIA2 protein is able to regulate the expression of plastid-specific ribosomal genes in the nucleus, and sequentially controls the translational machinery in chloroplasts. This research is supported by grants to C-W Sun and H-M Li from the National Science Council of Taiwan.