Knock-out analysis of duplicated socs1 using CRISPR/Cas9 in Megalobrama amblycephala

In this study, the suppressor of cytokine signaling 1 (SOCS1) genes socs1a and socs1b of Megalobrama amblycephala were used as genetic editing objects, and we screened out appropriate target synthetic guide RNA (gRNA) by online analysis. According to the mixture injection (gRNA and Cas9 protein) in the 1-2 cell stage embryos, the results of identifications of socs1 expression level by qRT-PCR and gene mutants by sequencing showed that we successfully established socs1 knock-out mutant. Compared with wild type, the growth performance and body mass of SOCS1a^+/− and SOCS1b^+/− were significantly increased, Meanwhile, the expression levels of inflammatory cytokines TNF-α and IL-6 were significantly increased, while the expression levels of IL-1β were not changed. After Aeromonas hydrophila injection, in contrast to the wild type, significant increases in levels of IL-6 and TNF-α mRNA were observed in both socs1a and socs1b heterozygous mutants. The duplicated socs1 knockout blunt snout bream has been successfully obtained by the CRISPR/Cas9 gene editing system, which provides a basis for further study of the socs1 gene. Meanwhile, our experimental results will provide a basis and reference for the CRISPR/Cas9 gene editing techniques in other aquaculture species.