Maturation and translation mechanisms involved in the expression of a myb gene of rice.

We have isolated two overlapping cDNAs coding for a MYB-related protein expressed in aerobic and anaerobic rice (Oryza sativa) roots and coleoptiles. Analysis of their sequences reveals some peculiar features, suggesting the presence of post-transcriptional regulation events: an upstream ORF, two unspliced introns and a putative leucine zipper in the ORF coded by the unspliced RNA. Transient expression in protoplasts indicates that the upstream ORF inhibits expression of a downstream coding sequence. Finally, we demonstrated that anoxia, in roots, increases the ratio between the spliced and the unspliced mRNA and affects the expression of other myb-related genes.