A high-throughput screen identifies RNA binding proteins that affect fertility inCaenorhabditis elegansand reveals a functional relationship between ADR-2 and SQD-1

Abstract

ABSTRACTRNA binding proteins play essential roles in coordinating germline gene expression and development in all organisms. Characterization of gross fertility defects, such as sterility, has identified RNA binding proteins that are critical regulators of germline gene expression; however, broader screens for RNA binding proteins involved in specific reproductive processes are lacking. Here, a reverse genetic screen was performed to identify RNA binding proteins that impact yolk and embryo production inCaenorhabditis eleganshermaphrodites. This screen makes use of animals expressing a vitellogenin (yolk protein) fusion with green fluorescent protein, in a genetic background that corrects for a previously identified fertility defect in this strain. From this screen, we identified 23 RNA binding proteins that regulate embryo production inCaenorhabditis elegans. This screen lays groundwork for future interrogations into the molecular roles of these proteins in yolk production and embryogenesis. Additionally, the screen uncovered a genetic interaction between ADR-2, a member of the Adenosine DeAminase Acting on RNA (ADAR) family, and SQD-1, a member of the heterogenous nuclear ribonucleoprotein (hnRNP) family. Transcriptome-wide assessment in animals depleted ofsqd-1revealed over 8000 misregulated transcripts, suggesting SQD-1 is a major regulator of gene expression. Consistent with this, microscopy and reproductive assays reveal thatsqd-1is essential for oogenesis. In the absence ofadr-2, the effects of loss ofsqd-1on gene expression are attenuated, as well as the defects in oogenesis. Together, these data indicate that both ADR-2 and SQD-1 are important regulators of germline gene expression and oogenesis.Article SummaryThe molecular information that controls early development is RNA. Interactions between RNA and RNA binding proteins are critical for successful reproduction across species. In this study, over 250 RNA binding proteins were assessed for effects on yolk and embryo production inCaenorhabditis elegans. Twenty-three regulators of these important reproductive steps were identified, including 7 novel regulators. This screen also revealed a genetic interaction between two RNA binding proteins, SQD-1 and ADR-2, which impacts germline gene expression, oogenesis, and fertility.