Analysis Offgf20-Regulated Genes In Organ Of Corti Progenitors By Translating Ribosome Affinity Purification

Background Understanding the mechanisms that regulate hair cell (HC) differentiation in the organ of Corti (OC) is essential to designing genetic therapies for hearing loss due to HC loss or damage. We have previously identified Fibroblast Growth Factor 20 (FGF20) as having a key role in HC and supporting cell differentiation in the mouse OC. To investigate the genetic landscape regulated by FGF20 signaling in OC progenitors, we employ Translating Ribosome Affinity Purification combined with Next Generation RNA Sequencing (TRAPseq) in theFgf20lineage. Results We show that TRAPseq targeting OC progenitors effectively enriched for RNA from this rare cell population. TRAPseq identified differentially expressed genes (DEGs) downstream of FGF20, includingEtv4,Etv5,Etv1,Dusp6,Hey1,Hey2,Heyl,Tectb,Fat3,Cpxm2,Sall1,Sall3, and cell cycle regulators such asCdc20. Analysis ofCdc20conditional-null mice identified decreased cochlea length, while analysis ofSall1-null andSall1-Delta Zn2-10mice, which harbor a mutation that causes Townes-Brocks syndrome, identified a decrease in outer hair cell number. Conclusions We present two datasets: genes with enriched expression in OC progenitors, and DEGs downstream of FGF20 in the embryonic day 14.5 cochlea. We validate select DEGs via in situ hybridization and in vivo functional studies in mice.