Open AccessAmplification of the uvrA gene product of Escherichia coli to 7% of cellular protein by linkage to the pL promoter of pKC30.
Author(s) -
George H. Yoakum,
Anthony T. Yeung,
William B. Mattes,
Lawrence I. Grossman
Publication year - 1982
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.79.6.1766
Subject(s) - plasmid , gene , escherichia coli , biology , microbiology and biotechnology , gene product , transcription (linguistics) , population , gene expression , genetics , chemistry , linguistics , philosophy , demography , sociology
We have constructed a hybrid pKC30-uvrA plasmid (pGHY5003) in which transcription of the uvrA gene can be induced under pL control to amplify the uvrA gene product to 7% of cellular protein. To construct pGHY5003, we developed a genetic selection using the basal level of expression (30 degrees C) from pL in thermosensitive cI857 lysogens to isolate appropriately tailored repair genes inserted at the Hpa I site of pKC30 from recombinant DNA mixtures with a variety of products. In addition, a post-UV-irradiation radiolabeling method was adapted to screen inserts for temperature-inducible polypeptide synthesis directed by transcription under pL control rapidly. This should prove generally useful for isolating genes inserted at the Hpa I site of plasmid pKC30 with the following characteristics: (i) genetically functional hybrid plasmids selected from a large population of exonucleolytically tailored fragments ligated into Hpa I of pKC30 and (ii) production of high-level amplification for the gene product of interest by screening for post-UV-irradiation temperature inducibility of polypeptides synthesized from hybrid plasmids. The level of amplification obtained for the uvrA gene product from pGHY5003 is approximately 10,000-fold higher than estimates of the level of uvrA protein in logarithmic phase Escherichia coli.