Abstract: M7 lysin is located in the mussel sperm acrosome.As an important protein for fertilization,it can dissolve vitelline membrane and determine the specificity of sperm-egg recognition of mussel.At present,the M7 lysin sequences ofMytilus edulis Linnaeus,M.galloprovincialis and M.trossulus have been recognized,but it hasn’t been reported in M.coruscus. In this study,we cloned M7 lysin of M.coruscus with homology cloning method,and it was expressed in E.coli Rosseta(DE3).The results showed that the amplified product was about 540 bp fragment.The further sequencing revealed that the cDNA of open reading frame was 543 bp,and it had high similarity with those of M.edulis,M.galloprovincialis and M.trossulus.The protein included 180 amino acids through online translation,its molecular weight was 20 ku,and its isoelectric point was 8.48.The phylogenetic tree from the amino acid sequence of M7 lysin showed that M.edulis and M.galloprovincialis had closest relationship,followed by M.trossulus, and finally M.coruscus. The results suggested that M7 lysin could be used as molecular markers to study mussel’s evolution.The protein of 25 ku was showed in SDS-PAGE when M7 lysin was expressed in the prokaryotes,which included the amino acid sequences in vector.This band was consistent with the expected molecular weight.Disulfide bonds’ positions in M7 lysin were highly conservative,which was similar to C-type lectin carbohydrates identification area(CRD).We speculated that M7 lysin dissolved the yolk membrane through combining its sugar and sugar-based protein.The conclusions helped us to reveal the mussel’s reproductive mechanism,and further provide a reference for the cross breeding of mussels.