The Snail Family Member Worniu Is Continuously Required in Neuroblasts to Prevent Elav-Induced Premature Differentiation

SummarySnail family transcription factors are best known for regulating epithelial-mesenchymal transition (EMT). The Drosophila Snail family member Worniu is specifically transcribed in neural progenitors (neuroblasts) throughout their lifespan, and worniu mutants show defects in neuroblast delamination (a form of EMT). However, the role of Worniu in neuroblasts beyond their formation is unknown. We performed RNA-seq on worniu mutant larval neuroblasts and observed reduced cell-cycle transcripts and increased neural differentiation transcripts. Consistent with these genomic data, worniu mutant neuroblasts showed a striking delay in prophase/metaphase transition by live imaging and increased levels of the conserved neuronal differentiation splicing factor Elav. Reducing Elav levels significantly suppressed the worniu mutant phenotype. We conclude that Worniu is continuously required in neuroblasts to maintain self-renewal by promoting cell-cycle progression and inhibiting premature differentiation.

Graphical AbstractFigure optionsDownload high-quality image (239 K)Download as PowerPoint slideHighlights
► Worniu regulates multiple processes to maintain neuroblast “stemness”
► worniu prevents the upregulation of neural differentiation genes, including Elav
► Upregulated Elav in worniu mutants inhibits neuroblast cell cycle and polarity
► Overexpressing Worniu elevates nuclear Prospero, which inhibits self-renewal