RNA recognition by the C. elegans oocyte maturation determinant OMA-1

Abstract Maternally supplied mRNAs encode proteins that pattern early embryos in many species. In the nematode Caenorhabditis elegans, a suite of RNA-binding proteins regulates expression of maternal mRNAs during oogenesis, the oocyte-to-embryo transition, and early embryogenesis. To understand how these RNA-binding proteins contribute to development, it is necessary to determine how they select specific mRNA targets for regulation. OMA-1 and OMA-2 are redundant proteins required for oocyte maturation, an essential part of meiosis that prepares oocytes for fertilization. Both proteins have CCCH-type tandem zinc finger (TZF) RNA-binding domains. Here, we define the RNA-binding specificity of OMA-1, and demonstrate that OMA-1/2 are required to repress the expression of a glp-1 3′UTR reporter in developing oocytes. OMA-1 binds with high affinity to a conserved region of the glp-1 3′UTR previously shown to interact with POS-1 and GLD-1, RNA-binding proteins required for glp-1 reporter repression in the posterior of fertilized embryos. Our results reveal that OMA-1 is a sequence specific RNA-binding protein required to repress expression of maternal transcripts during oogenesis, and suggest that interplay between OMA-1 and other factors for overlapping binding sites helps to coordinate the transition from oocyte to embryo.