Brassinosteroids (BRs) are essential phytohormones regulating various developmental and physiological processes during normal growth and development.cog1-3D(cogwheel1-3D) was identified as an activation-tagged genetic modifier ofbri1-5, an intermediate BR receptor mutant in Arabidopsis (Arabidopsis thaliana).COG1encodes a Dof-type transcription factor found previously to act as a negative regulator of the phytochrome signaling pathway.cog1-3Dsingle mutants show an elongated hypocotyl phenotype under light conditions. A loss-of-function mutant or inducible expression of a dominant negative form ofCOG1in the wild type results in an opposite phenotype. A BR profile assay indicated that BR levels are elevated incog1-3Dseedlings. Quantitative reverse transcription-polymerase chain reaction analyses showed that several key BR biosynthetic genes are significantly up-regulated incog1-3Dcompared with those of the wild type. Two basic helix-loop-helix transcription factors,PIF4andPIF5, were found to be transcriptionally up-regulated incog1-3DGenetic analysis indicated that PIF4 and PIF5 were required for COG1 to promote BR biosynthesis and hypocotyl elongation. Chromatin immunoprecipitation and electrophoretic mobility shift assays indicated that COG1 binds to the promoter regions ofPIF4andPIF5, and PIF4 and PIF5 bind to the promoter regions of key BR biosynthetic genes, such asDWF4andBR6ox2, to directly promote their expression. These results demonstrated that COG1 regulates BR biosynthesis via up-regulating the transcription ofPIF4andPIF5.
- MeSH
- Arabidopsis genetika metabolismus MeSH
- biologické modely MeSH
- biosyntetické dráhy genetika MeSH
- bodová mutace genetika MeSH
- brassinosteroidy biosyntéza MeSH
- ethylmethansulfonát MeSH
- fenotyp MeSH
- hypokotyl růst a vývoj metabolismus MeSH
- promotorové oblasti (genetika) genetika MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné geny MeSH
- sekvence nukleotidů MeSH
- suprese genetická MeSH
- transkripční faktory bHLH genetika metabolismus MeSH
- transkripční faktory genetika metabolismus MeSH
- upregulace genetika MeSH
- vazba proteinů genetika MeSH
- Publikační typ
- časopisecké články MeSH