RESUMEN
Objective:To construct a fusion protein of extracellular domain peptide fragment of muscle specific kinase ( MuSK) and fluorescent protein mCherry ,and used as antigen in the detection of antibodies against MuSK ( MuSKAb ) in the sera of patients with myasthenia gravis ( MG).Methods:The mCherry gene was amplified by PCR from vector pRSET-B and cloned into pGEM-T Easy Vector,and furthermore, cloned into Eukaryotic expression vector pMT /BiP/V5-His ( MuSK), which contains MuSK extracellular domain 22-452 amino acid peptide fragment gene to construct the fluorescent fusion protein gene MuSK -mCherry.The recombinant vector was subsequently transfected into drosophila S 2 cells for expression.The expressed fusion proteins were verified in confocal mi-croscope ,and used as antigen in the detection of MuSKAb in sera of MG patents in fluorescence immunoprecipitation test .Results:The fluorescent fusion protein MuSK-mCherry was successfully constructed and expressed.The MuSKAb in sera of patents with MG could be detected in fluorescence immunoprecipitation test using the constructed MuSK-mCherry fusion protein as antigen.Conclusion: It is available to use the constructed fluorescent fusion protein MuSK-mCherry as antigen in fluorescence immunoprecipitation test for the detection of MuSKAb in sera of patents with MG.