title: Analyzing the metabolic stress response of recombinant Escherichia coli cultures expressing human interferon-beta in high cell density fed batch cultures using time course transcriptomic data.
abstract: Fed batch cultures expressing recombinant interferon beta under the T7 promoter were run with different exponential feeding rates of a complex substrate and induced at varying cell densities. Post-induction profiles of the specific product formation rates showed a strong dependence on the specific growth rate with the maximum product yield obtained at 0.2 h(-1). A study of the relative transcriptomic profiles as a function of pre-induction μ was therefore done to provide insight into the role of cellular physiology in enhancing recombinant protein expression. Hierarchical clustering analysis of the significantly regulated genes allowed us to identify biologically important groups of genes which fall under specific master regulators. The groups were: rpoH, ArcB, CreB, Lrp, RelA, Fis and Hfq. The response of these regulators, which exert a feedback control on the growth and product formation rates correlated well with the expression levels obtained. Thus at the optimum pre-induction μ, the alternative sigma factors and ribosomal machinery genes did not get depressed till the 6th hour post-induction unlike at other specific growth rates, demonstrating a critical role for the genes in sustaining recombinant protein expression.
authors: School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
authors: Anuradha B
authors: AB
authors: Singh
authors: Ashish K
authors: AK
authors: Sharma
authors: Krishna J
authors: KJ
authors: Mukherjee
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D019149:Bioreactors; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism; D006801:Humans; D016899:Interferon-beta / Q000096:biosynthesis*; D008025:Ligases / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis; D012097:Repressor Proteins / Q000378:metabolism; D013312:Stress, Physiological; D059467:Transcriptome
chemical_list: D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; C041610:arcA protein, E coli; D016899:Interferon-beta; D011494:Protein Kinases; C065271:arcB protein, E coli; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases