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Brassinosteroid signal transduction - molecular genetics studies...

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  • Writer 이태화
  • 2014-01-22

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[분자.생명과학부/생물공학연구소 공동세미나]



 



제 목 : Brassinosteroid signal transduction - molecular genetics studies and beyond.






연 사 : Zhi Yong Wang [Department of Plant Biology]






일 시 : 2007년 5월 30일(수) 오후 2:45~3:45






장 소 : 생명과학과 1층 세미나실 104호



 



Abstract


     Brassinosteroids (BRs) play an essential role in plant growth and development. BR deficiency or insensitivity leads to a wide range of growth defects, including dwarfism, male sterility, delayed flowering, and light-grown morphology in the dark. Molecular genetic studies of Arabidopsis mutants with altered BR sensitivities have identified several BR signal transduction components, including two cell surface receptor-like kinases (BRI1 and BAK1), a GSK3-like kinase (BIN2), a phosphatase (BSU1), and two homologous transcription factors (BZR1 and BZR2/BES1). Subsequent biochemical and molecular biological studies have revealed the mechanisms of their functions and identified their interacting proteins as additional components of the BR signal transduction pathway. These studies demonstrate that when BR levels are low, BIN2 phosphorylates BZR1 and BZR2/BES1 to reduce their accumulation in the nucleus as well as their DNA binding activities. BRs bind to the extracellular domain of BRI1 to activate its kinase activity. Activated BRI1 dimerizes with and activates BAK1, which leads to inhibition of the BIN2 kinase, allowing dephosphorylation of the BZR1 and BZR2 /BES1 by the BSU1 phosphatase. Unphosphorylated BZR1 and BZR2 /BES1 bind to the promoters of target genes, which have been identified by chromatin immunoprecipitation coupled with microarray analysis. The network of BR-target genes connects BR signaling with specific developmental and physiological responses. Finally, the missing components of the BR signaling pathway are being identified by proteomic, biochemical, and refined genetic studies. These studies further establish the BR signaling pathway as a paradigm for cell-surface receptor kinase-mediated signal transduction underlying plant responses to environmental and hormonal signals.



 



※ 문의 : 생명과학과 황인환교수 (☎ 279-2128) ※




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