From owner-cellbiol@net.bio.net Tue Feb 25 22:00:00 1997 Path: biosci!rutgers.rutgers.edu!uwm.edu!cs.utexas.edu!howland.erols.net!cam-news-hub1.bbnplanet.com!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!dispatch.news.demon.net!demon!genesys.demon.co.uk!genesys.demon.co.uk!duncan From: "Dr. Duncan Clark" Newsgroups: bionet.microbiology,bionet.molbio.proteins,bionet.cellbiol Subject: Re: Temperature control in the T7 RNA polymerase/promoter system. (For protein expression)? Date: Wed, 26 Feb 1997 15:40:15 +0000 Organization: GeneSys Ltd Distribution: world Message-ID: References: <5f0jic$1ete$1@snunews.snu.ac.kr> NNTP-Posting-Host: genesys.demon.co.uk X-NNTP-Posting-Host: genesys.demon.co.uk MIME-Version: 1.0 X-Newsreader: Turnpike Version 3.01 Lines: 28 Xref: biosci bionet.microbiology:9090 bionet.molbio.proteins:10099 bionet.cellbiol:6767 In article <5f0jic$1ete$1@snunews.snu.ac.kr>, newera@plaza.snu.ac.kr writes >Why is the temperature control for growing E. coli under the T7 RNA >polymerase/promoter system required? The induction of T7 RNA polymerase in this system is temperature controlled. The T7 RNA pol is downstream of a lambda PL promoter which in turn is controlled by a temperature sensitive cI repressor gene. the heat shift from 30 to 42 inactivates the cI repressor, inducing expression of the T7 pol. Once the T7 pol is produced it in turn controls the overexpression of the gene down stream of the T7 promoter. Lambda PL promoters and the cI857 expression system have been around for years before the T7 expression system. It's just in this case onentrols the other. In my hands this sometimes give better expression than BL21(DE3) inducing the T7 RNA pol with IPTG. Duncan -------------------------------------------------------------------------------- The problem with being on the cutting edge is that you occasionally get sliced from time to time.... Duncan Clark DNAmp Ltd. TEl/FAX 01252376288 http://www.dnamp.com http://www.genesys.demon.co.uk .