The GATA Factor elt-1 Regulates C. elegans Developmental Timing by Promoting Expression of the let-7 Family MicroRNAs

Postembryonic development in caenorhabditis elegans is a powerful model for the study of the temporal regulation of development and for the roles of micrornas in controlling gene expression. stable switch-like changes in gene expression occur during development as stage-specific micrornas are expressed and subsequently down-regulate other stage-specific factors,driving developmental progression. key genes in this regulatory network are phylogenetically conserved and include the post-transcriptional microrna repressor lin-28; the nuclear hormone receptor daf-12; and the micrornas lin-4,let-7,and the three let-7 family mirnas (mir-48,mir-84,and mir-241). daf-12 is known to regulate transcription of mir-48,mir-84 and mir-241,but its contribution is insufficient to account for all of the transcriptional regulation implied by the mutant phenotypes. in this work,the gata-family transcription factor elt-1 is identified from a genetic enhancer screen as a regulator of developmental timing in parallel to daf-12,and is shown to do so by promoting the expression of the let-7,mir-48,mir-84,and mir-241 micrornas. the role of elt-1 in developmental timing is shown to be separate from its role in cell-fate maintenance during post-embryonic development. in addition,analysis of chromatin immnoprecipitation (chip) data from the modencode project and this work suggest that the contribution of elt-1 to the control of let-7 family microrna expression is likely through direct transcription regulation. © 2015 cohen et al.