PARENT SESSION
Posters P3D Genomic, proteomic and related technologies. Abstracts (720-730)

Chloroplastic RNase in Arabidopsis. Masahiro Kishine^*,1, Atsushi Takabayashi¹, Tsuyoshi Endo¹, Fumihiko Sato¹, ¹ Graduate School of Biostudies, Kyoto, Japan

ABSTRACT- Many characteristics of the gene expression system in chloroplast resemble those of bacteria because chloroplast is believed to have an evolutionally prokaryotic origin. To understand the physiological roles of homologue genes of bacterial RNases which localization are expected to be in chloroplast, we screened Arabidopsis mutants with the disruption by T-DNA. Based on the analysis of leaf color, growth and chlorophyll fluorescence, we identified three putative chloroplastic RNase mutants; polynucleotide phosphorylase (PNPase), RNase R and RNase E. PNPase mutant have etiolated leaves in proximal regions. RNase R and RNase E mutants could not grow photoautotrophically. Further RNA gel blot analysis for chloroplast rRNA and mRNA indicated that PNPase mutant accumulated slightly longer RNA than the mature RNA, probably due to the unprocessing 3′ RNA end. RNase R mutant showed the reduced accumulation of all rRNA species, suggesting the essential function in rRNA maturation. RNase E mutants showed the accumulation of precursor of rbcL operon. These results indicate the importance of RNases for efficient RNA metabolism in chloroplast and chloroplast function.

KEY WORDS: RNase