| Research Abstract |
A cDNA library was constructed with poly(A)^+RNA prepared from 10-day-old rice seedlings. I have isolated three nuclear genes, rpl9, rpl12-1, rpl12-2, rpl13, rpl15, rp121, rpl24, rpl28, rps1 and rps9, that encode chloroplast ribosomal proteins L9, L12, L13, L15, L21, L24, L28, S1 and S9 respectively. Using these clones as probes, these nuclear encoded genes were located on molecular linkage map of rice. Seven loci were located on 5 differnt chromosomes of rice. They were not clustered but dispersed throughout the rice genome.
Expression analysis of rpl12-1, rpl12-2, rpl13, rpl24 by Northern blotting reveals that these genes were expessed in leaves of 10-day-old rice seedlings regardless of the presence of light, but not in roots. These data suggest that nuclear encoded ribosomal protein genes were expressed in an organ specific manner.
The genomic clones of rpl13 and rpl24 were isolated, and transcription start sites were determined by S1-nulcease mapping and primer extension. It is suggested that both genes have multiple sites of transcription initiation, and that each site was employed for transcription initiation differently in specific organ.
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