Abstract
The ribosome plays a critical role in leaf morphogenesis in Arabidopsis thaliana. Loss-of-function mutants of ribosomal protein (r-protein) develop pointed leaves. We have isolated more than 20 mutants exhibiting such a phenotype. We found that the adaxial defect of asymmetric leaves2 (as2) was enhanced by these mutations, especially rpl4d. These results suggest that r-protein genes have a role for establishing the abaxial-adaxial polarity. But, how the ribosome regulates specific gene expression is not known. In order to assess whether the r-protein gene contributes to the activation of adaxial genes or the repression of abaxial genes, RPL4D with a target sequence of tasiR-ARF or microRNA165/166 was introduced into the as2 rpl4d double mutant. These constructs are expected to allow abaxial or adaxial region-specific expression of RPL4D. We are now investigating the effects of the region-specific expression of RPL4D on the establishment of an abaxial-adaxial polarity. We will discuss possible mechanisms of the regulation of abaxial-adaxial polarity via r-protein genes.
