Randy Scholl

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. Since trichothecenes are produced by some plant pathogenic fungi, we are studying Arabidopsis ribosomal protein L3 (ARP). Our previous studies have shown that there are three members of the ARP family, one of which (ARP1) is very abundant at the RNA level in all studied tissues, a second (ARP2) which is rarer and a third (ARP3) which is a processed pseudogene. The mRNA of ARP2 occurs largely in the poly(A)- fraction of all tissues examined, which is often associated with regulatory effects. 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. ARP2 has relatively high expression in roots, and the significance of this is being examined. Phenotypic effects of ARPs are being studied via reverse genetics.