Abstract
Dof5.8 transcription factor is expressed in provascular cells of leaf primordium in Arabidopsis. Here we show possible involvement of Dof5.8 in vascular development. Based on similar cell-type specificities of the promoters for Dof5.8 and an auxin-responsive marker DR5, we investigated auxin- and the auxin-responsive MONOPTEROS (ARF5) transcription factor-dependent activation of the Dof5.8 promoter in protoplasts. The result revealed that the Dof5.8 promoter and the promoter of OBP1 (Dof3.4), the closest gene of Dof5.8, were similarly activated by auxin and MONOPTEROS. Furthermore, both the provascular-specific expression and the MONOPTEROS-dependent activation of Dof5.8 were shown to require the 5' upstream region of the gene. The ectopic expression of Dof5.8 using the DEX inducible system delayed the xylem differentiation from procambial cells. These results suggest that Dof5.8 is one of the target genes of MONOPTEROS in vascular development in leaves. (This work was supported by PROBRAIN.)
