Abstract: microRNA (miRNA) is a class of non-coding RNA, which usually regulates target genes by bonding with the 3′noncoding region (3′UTR) of mRNA and forms an induced silence complex. There is an intimate connection between miR-155 and immunity. Also, miR-155 plays irreplaceable role in differentiation and function of immune cells, including dendritic cells, macrophages, B cells and T cell. There are collected 25 kinds of miR-155 species in miRBase datebase, ranging from coelenterate to human being and other higher animals. Among them there are six kinds of aquatic animals, including the Atlantic salmon, zebrafish, spot fork tail madtoms, catfish, and brocade carp, etc. For providing references for the study of the function of miR-155, we reviewed the immune function of miR-155, the progress of its target genes and the researches in aquatic animals.

Key words: target genes, miR-155；immune regulation, aquatic animals