UBE2G1 Is a Critical Component of Immune Response to the Infection of in Large Yellow Croaker ().

The large yellow croaker () is one of the most economically valuable mariculture fish in China. Infection of can cause an outbreak of "internal organ white-spot disease", which seriously affects the aquaculture of the large yellow croaker. Ubiquitylation is closely related to the post-translation modification of proteins and plays a vital role in many hosts' immune defense pathways, while the E2-binding enzyme is a key factor in ubiquitination. Our previous genome-wide association study found that the ubiquitin-binding enzyme E2G1 (designed ) was one of the candidate genes related to disease resistance in large yellow croaker. In this study, we analyzed the molecular characteristics, function, and immune mechanism of the . The full-length cDNA is 812 bp, with an open reading frame of 513 bp, encoding 170 amino acid residues. The results of the RT-qPCR and immunohistochemistry analysis revealed that its transcription and translation were significantly activated by the infection of in large yellow croaker. Immunocytochemistry experiments verified the co-localization of UBE2G1 and the ubiquitin proteins in the head kidney cells of large yellow croaker. Through GST pull-down, we found that UBE2G1 interacted with NEDD8 to co-regulate the ubiquitination process. The above results indicate that UBE2G1 is essential in the regulation of ubiquitination against infection in large yellow croaker, which lays a foundation for further study on the resistance mechanism of internal organ white-spot disease.