Functional analysis of decapping and EVH1/WH1 domains in dDcp1,Drosophila Decapping protein 1.
Date Issued
2004
Date
2004
Author(s)
Lee, Pei-Chen
DOI
en-US
Abstract
Based on the analysis of protein sequence, the human homologue of Drosophila CG11183, SMIF, a transcriptional co-activator, interacts with Smad4 by the EVH1/WH1 domain in N-terminal region of dDcp1 involving in transforming growth factorβ(TGFβ) signaling pathway. Thus, CG11183 was named dSMIF(Drosophila homologue of SMad Interacting Factor)originally. However, up to now, the evidences that CG11183 participate in TGFβ signaling pathway in vivo are not manifested certainly. Human SMIF was also identified as a decapping enzyme subsequently, named hDcp1a. CG11183 mutant results in the embryonic abdomen deletion phenotypes. It was proven that CG11183 possesses decapping activity involved in posterior localization and degradation regulation of osk mRNA. Therefore, we confirmed that CG11183 is a Drosophila decapping enzyme, dDcp1.
dDcp1 possesses two different molecular properties. The N-terminus of dDcp1 belongs to an EVH1/WH1 domain which is responsible for protein-protein interaction and the decapping activity of dDcp1 has been corroborated in vitro. In this thesis, to better understand the function of dDcp1 and the capability of EVH1/WH1 domain, we mutated the residues which are critical for decapping activity and ligand binding of EVH1/WH1 domain and expressed the mutant proteins in dDcp1 null background by transgenic flies to analyze the phenotype caused by these mutant proteins and the mechanism of dDcp1 posterior localization. To gain insight the mechanism of Dcp1 posterior localization, a series of dDcp1 deleted fragments are also used to analyze in the same experiment.
The residues responsible for decapping activity and protein-protein interaction in EVH1/WH1 domain are both required for Drosophila survival. The development of ovary is not affected substantially when the residues of dDcp1 which critical for decapping activity are mutated, but the embryos die in early embryogenesis. However, the posterior localization of dDcp1 is not affected. On the other hand, oocyte determination and polarity of oocyte are disrupted as the residues important to ligand binding are mutated but the posterior localization of dDcp1 is not affected. The results of deletion analysis display that dDcp1N300owns most of the biological activity sufficienlyt for oogenesis. And although the frangment, dDcp1N183, do not affect the expression of Osk , dDcp1N183 can not concentrate at the posterior pole of oocyte.
Subjects
去頭蓋酵素
果蠅
drosophila
decapping
EVH1/WH1
Type
other
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