Tissue Specific Regulation of Intestinal Proliferation through CDC-25.1 Export

@inproceedings{citeulike:3325564, abstract = {Alexandra Segref and Iain L. Johnstone. The cdc-25.1(ij48) hypermorphic allele has been previously identified in our lab in a mutant screen to detect animals with altered numbers of intestinal cells [1]. The ij48 lesion comprises a single S to F mutation (S46F) in a highly conserved putative N terminal DSG consensus site, which may act as a regulatory binding site for an F-box protein. Consistent with this notion, the CDC-25 protein is supplied maternally to all embryonic cells, but its abundance decreases and is undetectable after the 100 cell stage of embryogenesis [1]. Intriguingly, in cdc-25.1 ij48 mutants, proliferation of other tissues is unaffected, but removal of CDC-25 by RNAi results in reduced cell divisions in most or all lineages [1, 2]. Thus, there is general requirement for CDC-25 function in all embryonic blastomeres. Until now no obvious difference has been observed for the localisation or abundance of CDC-25 compared to CDC-25 S46F. Deciphering the mechanism that controls the site of the ij48 lesion will provide significant insights into the tissue specific regulation of the C. elegans cell cycle. We have performed an RNAi screen for candidates that negatively regulate CDC-25 andidentified an F-box protein, which mimics the ij48 intestinal specific cell proliferation phenotype when depleted from the embryo by RNAi. Knock-down of the F-box protein by RNAi in an ij48 background does not result in a synergistic effect, implying it may function through S46. In accordance with this result, CDC-25 protein levels are significantly increased in embryonic extracts derived from the ij48 mutant as compared to wild type and knock-down of the F-box protein does increase CDC-25 but not CDC-25 S46F protein levels. Surprisingly, the increased abundance of CDC-25 S46 is not restricted to intestinal cells suggesting the intestinal proliferation is more sensitive to CDC-25 protein levels than other cell types. We are currently examining whether the RNAi effect observed is the result of a direct physical interaction between CDC-25 and the F-box molecule.. 1.. Clucas, C., et al., Oncogenic potential of a C.elegans cdc25 gene is demonstrated by a gain-of-function allele. EMBO J, 2002. 21(4): p. 665-74.. 2.. Ashcroft, N.R., et al., RNA-Mediated interference of a cdc25 homolog in Caenorhabditis elegans results in defects in the embryonic cortical membrane, meiosis, and mitosis. Dev Biol, 1999. 206(1): p. 15-32..}, author = {Segref, Alexandra and Iain}, citeulike-article-id = {3325564}, citeulike-linkout-0 = {http://www.wormbase.org/db/misc/paper?name=WBPaper00027541}, journal = {European Worm Meeting}, keywords = {c\_elegans, caenorhabditis\_elegans, cdc-251, celegans, elegans, k06a57, meeting\_abstract, nematode, wormbase}, posted-at = {2008-09-23 22:05:32}, priority = {3}, title = {Tissue Specific Regulation of Intestinal Proliferation through CDC-25.1}, url = {http://www.wormbase.org/db/misc/paper?name=WBPaper00027541}, year = {2006} }

TY - CONF ID - citeulike:3325564 L3 - citeulike-article-id:3325564 N2 - Alexandra Segref and Iain L. Johnstone. The cdc-25.1(ij48) hypermorphic allele has been previously identified in our lab in a mutant screen to detect animals with altered numbers of intestinal cells [1]. The ij48 lesion comprises a single S to F mutation (S46F) in a highly conserved putative N terminal DSG consensus site, which may act as a regulatory binding site for an F-box protein. Consistent with this notion, the CDC-25 protein is supplied maternally to all embryonic cells, but its abundance decreases and is undetectable after the 100 cell stage of embryogenesis [1]. Intriguingly, in cdc-25.1 ij48 mutants, proliferation of other tissues is unaffected, but removal of CDC-25 by RNAi results in reduced cell divisions in most or all lineages [1, 2]. Thus, there is general requirement for CDC-25 function in all embryonic blastomeres. Until now no obvious difference has been observed for the localisation or abundance of CDC-25 compared to CDC-25 S46F. Deciphering the mechanism that controls the site of the ij48 lesion will provide significant insights into the tissue specific regulation of the C. elegans cell cycle. We have performed an RNAi screen for candidates that negatively regulate CDC-25 andidentified an F-box protein, which mimics the ij48 intestinal specific cell proliferation phenotype when depleted from the embryo by RNAi. Knock-down of the F-box protein by RNAi in an ij48 background does not result in a synergistic effect, implying it may function through S46. In accordance with this result, CDC-25 protein levels are significantly increased in embryonic extracts derived from the ij48 mutant as compared to wild type and knock-down of the F-box protein does increase CDC-25 but not CDC-25 S46F protein levels. Surprisingly, the increased abundance of CDC-25 S46 is not restricted to intestinal cells suggesting the intestinal proliferation is more sensitive to CDC-25 protein levels than other cell types. We are currently examining whether the RNAi effect observed is the result of a direct physical interaction between CDC-25 and the F-box molecule.. 1.. Clucas, C., et al., Oncogenic potential of a C.elegans cdc25 gene is demonstrated by a gain-of-function allele. EMBO J, 2002. 21(4): p. 665-74.. 2.. Ashcroft, N.R., et al., RNA-Mediated interference of a cdc25 homolog in Caenorhabditis elegans results in defects in the embryonic cortical membrane, meiosis, and mitosis. Dev Biol, 1999. 206(1): p. 15-32.. JF - European Worm Meeting TI - Tissue Specific Regulation of Intestinal Proliferation through CDC-25.1 KW - c_elegans KW - caenorhabditis_elegans KW - cdc-251 KW - celegans KW - elegans KW - k06a57 KW - meeting_abstract KW - nematode KW - wormbase AU - Segref, Alexandra AU - Iain PY - 2006/// UR - http://www.wormbase.org/db/misc/paper?name=WBPaper00027541 ER -