Synonymous Codon Usage Bias and Overexpression of a Synthetic Gene Encoding Interferon α2b in Yeast / 中国病毒学

To achieve higher level expression of Interferon α2b (IFN-α2b) in methylotrophic yeast (Pichia pastoris), a cDNA fragment coding for the mature IFN-α2b was designed and synthesized based on the synonymous codon bias of P. pastoris and optimized G+C content. The synthetic IFN-α2b was inserted into the secreted expression vector pPICZαA, and then integrated into P. pastoris GS115 genome by electroporation. Multi-copy integrants in the Mut+ recombinant P. pastoris strain were screened by high concentrations of Zeocin. 120 hours culturing allowed expression of the IFN-α2b transformant up to 810 mg/L as detected by SDS-PAGE and quantitative methods. In addition, Western blot analysis showed that the recombinant proteins had immunogenicity. The significant antiviral activity of the recombinant IFN-α2b protein was verified by WISH/ VSV system, which was 3.3×105 IU/mL.

Molecular Cloning and Sequencing of HCV E2 Gene / 中国病毒学

HCV RNA positive serum was first selected by RT-PCR test kit from several anti-HCV positive sera obtained from Xi'an.HCV RNA extrac ted from the elected sera was converted to cDNA by reverse transcription with ra ndom primer.Half-nested PCR was performed.The amplified product was 852 bp.The purified PCR product was digested by restriction endonucleases and then ligated to epressio vector pET-22b\++.Its nucleotide sequence was determined by dideoxy chain termination method.A comparison of the sequence with several isolates rep orted previously showed that the sequence belonged to HCV type Ⅱ.