GSE185172
Tbx2 and Tbx3 regulate cell fate progression of the otic vesicle for inner ear development
The morphogenesis of the otic vesicle (OV) to form inner ear organs serves as an excellent model system to understand cell fate acquisition on a single cell level. Tbx2 and Tbx3 (Tbx2/3) encode closely related T-box transcription factors that are expressed widely in the mammalian otic vesicle (OV). Inactivation of both genes in the Pax2-Cre lineage (Tbx2/3cKO) results in failed morphogenesis of the OV into inner ear organs. To understand the basis of these defects, single cell RNA-sequencing (scRNA-seq) was performed on the OV lineage using Pax2-Cre, in controls versus Tbx2/3cKO embryos, at stage E10.5. We identified a multipotent population termed otic progenitors that are localized to the anterior ventrolateral region of the OV in controls and are marked by expression of Fgf18, Sox3, and Cxcl12. The otic progenitor population was increased three-fold in Tbx2/3cKO embryos, concomitant with dysregulation of genes in these cells as well as reduced progression to more differentiated states of prosensory and nonsensory cells. An ectopic neural population of cells was detected in the posterior OV of Tbx2/3cKO embryos due to increased expression of Neurog1 and NeuroD1 but with reduced maturation. As all three cell fates were affected in Tbx2/3cKO embryos, we suggest that Tbx2/3 promotes progression of multipotent otic progenitors to more differentiated cell types in the OV. Overall design: Single Cell RNA-sequencing from micro dissected tissue around the otic vesicle and cochleovestibular ganglion of Pax2-Cre;Rosa26-GFPf/+ and Pax2-Cre;Tbx2f/f;Tbx3f/f;Rosa26-GFPf/+ embryos at E10.5