Effect of overexpression of Arabidopsis Dof5.8 from the MP promoter.
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ABSTRACT: Vascular formation in the leaves of higher plants begins with the selection of cells poised to become preprocambial cells, some of which eventually develop into procambial cells. The initiation of this process is accompanied by auxin-responsive and MONOPTEROS (MP) transcription factor-mediated modulations in gene expression. Here, we show that MP directly activates the expression of Dof5.8, which encodes a transcriptional repressor. Consistently, mutations within Dof5.8 enhanced the phenotype of a weak allele of mp, resulting in abnormal root and cotyledon development. However, although mp mutants showed reduced vascular patterns in cotyledons, the mp dof5.8 double mutants displayed both reduced and more complex vascular patterns in individual cotyledons. Thus, Dof5.8 appears to be associated with both positive and negative regulatory mechanisms for vascular network formation in leaves. Furthermore, both over-expression of Dof5.8 and expression of a Dof5.8 construct engineered to possess enhanced repressor activity in preprocambial cells prevented the formation of procambium for secondary and higher order veins, suggesting a predominantly negative regulatory role for Dof5.8. These results imply that proper vascular patterns in leaves are formed through the modulation of both positive and negative regulation by Dof5.8. MP may direct this fine-tuning mechanism by mediating the expression of Dof5.8. Gene expression in 4-day-old shoots was compared between the Dof5.8-overexpressing lines and control lines.
ORGANISM(S): Arabidopsis thaliana
SUBMITTER: Shuichi Yanagisawa
PROVIDER: E-GEOD-47808 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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