Evolution and Comparative Genomics of the Transforming Growth Factor-β-Related Proteins in Nile Tilapia

The members of the transforming growth factor β (TGF-β) family of cell signaling polypeptides have garnered a great deal of interest due to its capacity from nematodes to mammals to regulate cell-based activities which control the growth of embryos and sustain tissue homeostasis. The current study designed a computational analysis of the TGF-β protein family for understanding these proteins at the molecular level. This study determined the genomic structure of TGF-β gene family in Nile tilapia for the first time. We chose 33 TGF-β genes for identification and divided them into two subgroups, TGF-like and BMP-like. Moreover, the subcellular localization of the Nile tilapia TGF-β proteins have showed that majority of the members of TGF-β proteins family are present into extracellular matrix and plasma except BMP6, BMP7, and INHAC. All TGF-β proteins were thermostable excluding BMP1. Each protein exhibited basic nature, excluding of BMP1, BMP2, BMP7, BMP10, GDF2, GDF8, GDF11, AMH, INHA, INHBB, and NODAL M. All proteins gave impression of being unstable depending on the instability index, having values exceeding 40 excluding BMP1 and BMP2. Each TGF-β protein was found to be hydrophobic with lowered values of GRAVY. Moreover, every single one of the discovered TGF-β genes had a consistent evolutionary pattern. The TGF-β gene family had eight segmental duplications, and the Ka/Ks ratio demonstrated that purifying selection had an impact on the duplicated gene pairs which have experienced selection pressure. This study highlights important functionality of TGF-β and depicts the demand for further investigation to better understand the role and mechanism of transforming growth factor β in fishes and other species.