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Evidence that the C‐terminal domain (CtD) autoinhibits neural repression by Drosophila E(spl)M8
Author(s) -
Kahali Bhaskar,
Kim JeeEun,
Karandikar Umesh,
Bishop Clifton P.,
Bidwai Ashok P.
Publication year - 2010
Publication title -
genesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.093
H-Index - 110
eISSN - 1526-968X
pISSN - 1526-954X
DOI - 10.1002/dvg.20581
Subject(s) - ctd , phosphorylation , biology , psychological repression , microbiology and biotechnology , c terminus , drosophila (subgenus) , genetics , gene , amino acid , gene expression , oceanography , geology
Analysis of the retinal defects of a CK2 phosphomimetic variant of E(spl)M8 (M8S 159 D) and the truncated protein M8* encoded by the E(spl)D allele, suggest that the nonphosphorylated CtD “autoinhibits” repression. We have investigated this model by testing for inhibition (in “ trans ”) by the CtD fragment in its nonphosphorylated (M8‐CtD) and phosphomimetic (M8SD‐CtD) states. In N + flies, ectopic M8‐CtD compromises lateral inhibition, i.e., elicits supernumerary bristles as with loss of N signaling. This antimorphic activity of M8‐CtD strongly rescues the reduced eye and/or bristle loss phenotypes that are elicited by ectopic M8SD or wild type M8. Additionally, the severely reduced eye of N spl / Y ; E(spl)D /+ flies is also rescued by M8‐CtD. Rescue is specific to the time and place, the morphogenetic furrow, where “founding” R8 photoreceptors are specified. In contrast, the phosphomimetic M8SD‐CtD that is predicted to be deficient for autoinhibition, exhibits significantly attenuated or negligible activity. These studies provide evidence that autoinhibition by the CtD regulates M8 activity in a phosphorylation‐dependent manner. genesis 48:44–55, 2010. © 2009 Wiley‐Liss, Inc.