This project investigates how animal cells specialize to give rise to gametes (eggs and sperm). This Mid-Career Award will enable the PI, who is an expert in biochemistry, to gain expertise in molecular genetics and microscopy by working with a collaborator at a different institution. The project will also train students in classical RNA-protein biochemistry approaches as part of summer lab courses co-hosted by the PI and collaborator.<br/><br/>Transcriptional regulation of genes during development is insufficient to account for the observed temporal and spatial patterns in proteins required for differentiation and development. Instead, many mRNAs critical for development are also regulated at the level of translation initiation. Translation initiation is controlled by initiation factors such as eukaryotic initiation factor 4 (eIF4). In previous work, the PI’s lab studied how unique forms of the eIF4 protein selectively translate mRNA during the development of Caenorhabditis elegans, a simple nematode. The hypothesis for this proposal is that isoforms of eIF4E known as IFE-1 and IFE-3 selectively recruit dormant mRNAs to ribosomes for efficient protein synthesis. The first goal of this project is to use resolved polysome RNA Seq, a technology developed in the PIs lab, to identify all RNAs that rely on IFE-1 or IFE-3 for efficient translation. The second uses CRISPR/Cas9 technology to fluorescently tag each IFE to determine its localization in vivo, and allow characterization of its storage and retrieval complexes by proteomics.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.