Abstract
Rice EL5 gene encodes an ubiquitin ligase (E3) containing a trans-membrane motif and a RING-H2 finger domain. Since transgenic rice plants overexpressing mutated EL5 lacking E3 activity showed rootless phenotype, it is suggested that EL5 functions as E3 during crown root and lateral root development after meristem differentiation in rice.
In this study, we conducted expression analyses of the EL5. Northern-blot analyses revealed that EL5 mRNA was abundant in the basal region of shoots and roots. The expression was induced by auxin, cytokinin and jasmonic acid in the basal region, and by cytokinin and jasmonic acid in roots. Transgenic rice plants with the EL5 promoter::GUS gene showed strong GUS activity mainly in vascular bundles of the basal region of shoots. Cytokinin strongly induced the GUS activity in roots. Western-blot analyses indicated that EL5 was localized to membranes after N-terminal processing and regulated by its E3 activity.
