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Genomic analysis of high‐cell‐density recombinant Escherichia coli fermentation and “cell conditioning” for improved recombinant protein yield
Author(s) -
Gill R. T.,
DeLisa M. P.,
Valdes J. J.,
Bentley W. E.
Publication year - 2000
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/1097-0290(20010105)72:1<85::aid-bit12>3.0.co;2-h
Subject(s) - microbiology and biotechnology , biology , recombinant dna , fusion protein , gene , fusion gene , gene expression , t7 rna polymerase , escherichia coli , transcription (linguistics) , rna , cell , bacteriophage , biochemistry , linguistics , philosophy
The Escherichia coli stress gene transcription profile and response to recombinant protein overexpression were substantially altered at high cell density when compared with low cell density. Reverse trascription–polymerase chain reaction RT‐PCR‐amplified mRNA from low (4 g[DCW]/L) and high‐cell‐density (43.5 g [DCW]/L) conditions were hybridized with a DNA microarray of Kohara clones encompassing 16% of the E. coli genome, and differentially displayed genes were identified. Transcript‐specific RNA dot blots indicated that molecular chaperones ( groEL, ibpA, degP ), proteases ( degP, ftsH ), the lysis gene mltB , and DNA damage/bacteriophage‐associated gene transcript levels ( ftsH, recA, alpA, uvrB ) increased 10‐ to 43‐fold at high cell density. In addition, overexpression of recombinant green fluorescent protein (GFP uv )/chloramphenicol acetyltransferase (CAT) fusion protein did not change the rates of cell growth or cell lysis. The stress gene transcription profile at high cell density was used to evaluate “cell conditioning” strategies to alter the levels of chaperones, proteases, and other intracellular proteins prior to recombinant protein overexpression. Interestingly, the addition of 1 g/L dithiothreitol (DTT) 20 min prior to induction of a GFP uv /CAT fusion protein resulted in a twofold increase in CAT activity when compared with the unconditioned controls. In addition, RNA dot blots of five stress genes confirmed that cell conditioning strategies significantly altered the dynamic stress gene response to foreign protein overexpression. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 72: 85–95, 2001.