Upstream Elements Regulating mir-241 and mir-48

Abstract

Caenorhabditis elegans is a free-living nematode that has been extensively used to study developmental timing, an evolutionarily conserved and important process that when disrupted can contribute to the etiology of some congenital human diseases. While proteins are known to be important to developmental timing, studies in recent years have also indicated the importance of short, non-coding RNAs, called microRNAs, which control gene expression. mir-241, mir-48, and mir-84 are microRNAs that all belong to the let-7 family of microRNAs, which act redundantly to influence development in C. elegans. A mutant phenotype of these microRNAs suggests that they function in the lateral hypodermal seam cells. mir-241 and mir-48 reside together on chromosome V and seem to be under the control of some of the same regulatory sequences located upstream of mir-241, the “mir-241 promoter”. The goal of this project was to identify and characterize a specific seam cell enhancer element within this promoter. We hypothesized that a subfragment of a 750 bp sequence drives mir-241/mir-48 expression in the seam cells. The most consistent seam cell expression was seen from a 275 bp fragment, thus suggesting this promoter element is important in directing mir-241/mir-48 seam expression.