Elucidating the role of PHD-finger protein PHF5A in neural crest specification

Abstract

In vertebrates, the neural crest (NC) belongs to a migratory population of multipotent stem cells which arise at the interface between the neural and non-neural ectoderm. Our previous studies showed that a RhoGAP Deleted in Liver Cancer 1 (DLC1) plays an important role in governing NC specification through regulating the expression of NC specifier genes (SOX9, FOXD3 and SNAIL2) but the underlying mechanisms remain unknown. Here, by mass spectrometry, we identified a DLC1 interacting factor, PHD Finger Protein 5A (PHF5A) which has been implicated in regulating gene transcription[1] and splicing[2]. By in ovo electroporation, we found that CRISPR/Cas9-targeted PHF5A downregulated SOX9 expression while neural marker SOX2 was upregulated, indicating a cell fate switch from NC to neural. In addition to the in vivo interaction between DLC1-PHF5A, we further showed the association of DLC1 and PHF5A with a splicing factor 3B subunit 1 (SF3B1), suggesting a splicing complex to regulate gene expression at the post-transcriptional level[2]. Indeed, both DLC1 knockdown and PHF5A knockout resulted in intron retention of SOX9 and SNAIL2. Altogether, our findings reveal that a non-transcription factor DLC1 recruits PHF5A-SF3B1 complex to regulate pre-mRNA splicing of NC specifier genes, unravelling new molecular mechanism of NCC fate specification.