Molecular cloning of human FL gene and its expression in E.coli / 中国生化药物杂志

ABSTRACT

Purpose　The aim is to obtain the cDNA sequence of encoding extramembrane human FL gene with high level expression in E.coli. Methods　The primers were designed based on the known FL cDNA sequence. The total RNA was isolated from fetal liver cells , and then RT-PCR was performed. The fragment was cloned into pUC-18T vector, and further sequenced by automatic sequence analyzer. The gene was inserted into GST fusion expression vector between BamH Ⅰ and EcoR Ⅰ sites. The recombinant plasmid was transformed into E.coli strain DH5 α and induced with 1mmol/L IPTG.Results　The 546bp DNA fragment was amplified by RT-PCR method from fetal liver cells and its sequence was identical to the published sequence encoding human FL. The expressed fusion protein, with molecular weight of about 22kD, was about 10% of the total bacteria protein by SDS-PAGE and densitometry analysis.Conclusion　cDNA was cloned successfully. This study provided a basis for the further fundamental research and clinical application of FL.