TSPYL1 as a crucial regulator of TGFβ signalling in Epithelial-to-Mesenchymal Transition, 2022

Abstract

Testis-specific protein, Y-encoded-like 1 (TSPYL1) contains a highly conserved nucleosome assembly protein domain originally identified in TSPY. The TSPYL1 gene is ubiquitously expressed and homozygous mutations cause sudden infant death with dysgenesis of the testes syndrome. The function of TSPYL1 is entirely unknown. In this study, we discovered that knockdown of TSPYL1 induced Epithelial-to-Mesenchymal Transition (EMT) in both Be2C neuroblastoma cells and A549 lung carcinoma cells. TGF-β is a well-known EMT inducer. Knockdown of TSPYL1 promoted the TGF-βinduced Smad2/3 phosphorylation, confirming the upregulation of TGF-β signalling which might cause EMT. Subsequently, we identified the target genes of TSPYL1 through CUT&RUN sequencing. TGFBR1 was shortlisted for further study as it encodes the subunit of receptors for TGF-β. ChIP-PCR confirmed that TSPYL1 bound the promoter of TGFBR1. Furthermore, knockdown of TSPYL1 significantly increased the transcript and protein levels of TGFBR1. Mechanistically, we found that TSPYL1 interacted with FOXA1, a known repressor of EMT. Whether FOXA1 recruits TSPYL1 to the promoter of TGFBR1 is being tested. Collectively, our results demonstrate that TSPYL1 is a key negative regulator of EMT. TSPYL1 may co-operate with FOXA1 to repress the expression of TGFBR1, and serve to maintain the epithelial phenotype.