XPRESSION OF VITREOSCILLA HEMOGLOBIN GENE
透明颤菌血红蛋白基因在阿维链霉菌中的表达

Two expression vectors, pWY101 and pWY102, were constructed by cloning Vitreoscilla hemoglobin gene(vhb) with its native oxygen-regulated promoter into E. coli-Streptomyces shuttle vector plJ653. They were introduced into Streptomyces averrnitilis, but Western blotting experiment failed to detect vhb gene expression, pHZ1252 is another shuttle vector for expressing VHb, in which vhb structural gene is controlled by a strong, thiostrepton-inducible Streptomyces promoter PtipA' pHZ1252 was transformed into S. avermitilis and expressed VHb which had biological activity after thiostrepton induction, pHZ1252 was structurally unstable in S. averrnitilis, occurring deletion recombination. However, the rest part of pHZ1252 was stable in S. averrnitilis and still contained vhb gene and PtipA. Plasmid pHZ1252 isolated from S. averrnitilis was unable to transform E. coli, showing the loss of part of E. coli plasmid from pHZ1252.