Randy Scholl

Department of Plant Biology, Ohio State University, Columbus, Ohio

Ribosomal protein (RP) genes have been studied extensively in E. coli, yeast and animals. Many genetic traits are associated with RPs: Resistance to trichothecene mycotoxins is conferred by ribosomal protein L3 (RPL3) of yeast, and the minute phenotype of Drosophila is the result of mutant RPs. We are studying regulation of the genes encoding Arabidopsis ribosomal protein L3 (ARP). Two genes of this family are expressed at the RNA level, one of which (ARP1) is very abundant at the RNA level in all studied tissues the second (ARP2) which is rarer. Differential expression among tissues of the two messages has been observed. The mRNA of ARP2 occurs largely in the poly(A)- fraction of all tissues examined. The role of flanking sequences in controlling differential polyadenylation and expression of ARP1 and ARP2 is being assessed. ARP2 is shown, by polysome analysis, to be translated. Assessment of whether the translated ARP2 mRNA is polyadenylated has been conducted. Phenotypic effects of ARPs are being studied via reverse genetics. Examination of relative expression at the protein level is also in progress.