Structural and functional analysis of transforming growth factor beta regulator 1 (TBRG1) in the red swamp crayfish Procambarus clarkii: The initial insight into TBRG1's role in invertebrate immunity

Abstract

The transforming growth factor beta regulator 1 (TBRG1) is a growth inhibitory protein that acts as a tumor suppressor in human cancers, gaining its name for the transcriptional regulation by TGF-β. While extensive research has been conducted on the tumor-related function of TBRG1 in mammals, its significance in invertebrates remains largely unexplored. In this study, a homolog of TBRG1 was first structurally and functionally analyzed in the red swamp crayfish Procambarus clarkii. The full-length cDNA sequence was 2143 base pairs (bp) with a 1305 bp open reading frame (ORF) encoding a deduced protein of 434 amino acids (aa). The changes of PcTBRG1 transcripts upon immune challenges indicated its involvement in innate immunity. After knocking down PcTBRG1, the decline of bacteria clearance capacity revealed the participation of PcTBRG1 in the immune response. Furthermore, the downregulation of AMPs' expression after the cotreatment of RNAi and bacteria challenge suggested that PcTBRG1 might participate in innate immunity through regulating AMPs’ expression. These results provided initial insight into the immune-related function of TBRG1 in invertebrates.