| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
In this study, we analyzed the expression of three chioroplast RNA polymerase sigma factor genes (sigA, sigB and sigC) isolated from the nuclear genome of the unicellular red alga, Cyanidium caldarium RK-1. Total RNA was isolated periodically during the culture under 12 hours / 12 hours light dark cycles, and the expression of the sig mRNAs were analyzed by northern hybridization methods. While the sigA mRNA was detected irrespective of the light condition, the sigB and/or sigC mRNA was detected only from the RNA from the light conditioned cells. Therefore, these sigma factor genes are shown to be differentially photo-regulated by the external light condtions. Since Cyanidium cells are extremely hard to disrupt, and not suitable for the biochemical analysis, we subsequently isolated the chioroplast sigma factor genes from another unicellular red alga, Cyanidioschyzon merolae. We isolated two genes, sigA and sigB, that correspond to the sigA and sigB (sigC) genes of C.caldarium, respectively. The expression of these sigma factor genes as well as the representative chloroplast genes, rbcL, psbA and cpcG, were monitored by northern hybridization analysis. All of the examined genes were found to be induced by lights. However, each expression pattern has specific pattern, and differential regulations were strongly suggested.
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