Cloning and expression of human nerve growth factor subunit βin E.Coli

AIM: To obtain nerve growth factor subunit β(NGF β) gene from Chinese fetal hippocampus tissue, prove its sequence, clone the mature peptide sequence, and make it express in E.coli .METHODS: Total RNA was extracted, amplified by RT-PCR method. Its 650 bp DNA sequence was inserted into PCR Ⅱ vector. PCR/NGF β vector was used as the template to amplfy the C-terminate mature peptide sequence, then subcloned it into PG5 vector. The recombinant was transferred into E.coli BL21. BL21 was cultured and induced by IPTG. The activity of the expressed product was measured after purified and refolded.RESULTS: A complete cDNA sequence was determined as 1 047 nucleotides. The cloned 636 bp encoding 212 amino acids was proved homological to Genbank by sequence analysis. The expressed mature peptide showed an clear band of the prospected 14 kD by SDS-PAGE electrophoresis, and was testified by Western blot. The expression level was about 10% of the total cell lysate. CONCLUSION: The chinese NGF β gene was homological to the foreigners'. The recombinant NGF β was efficiently expressed in E.Coli and the recombinant protein has high immunological activities.