| 摘要 |
PURPOSE:To ensure succession of parent and daughter cells and improve stability holding properties by containing a specific DMA fragment and a DNA fragment containing a structural gene capable of expressing with a promoter thereof. CONSTITUTION:A chromosomic DNA of Escherichia.coli is excised with restriction enzymes BamHI and Hind III to provide a tryptophanase operon DNA fragment of about 3.2kb length, which is then excised with restriction enzymes AluI and RsaI to afford a DNA fragment (A) of about 630 bp length containing a promoter of tryptophanase operon (tna) and a regulator gene tnaC on the downstream side of the promoter. A tryptophanase structural gene (tnaA) or tryptophanase synthase structural gene (trpA and trpB) is then contained to provide a DNA fragment (B). The fragments (A) and (B), a DNA fragment (S) derived from pBR322 and a DNA fragment (F) of mini-F fragment are contained to produce a plasmid pMTP4, etc. |
