PMID- 8857193
OWN - NLM
STAT- MEDLINE
DCOM- 19970206
LR  - 20191210
IS  - 8756-7938 (Print)
IS  - 1520-6033 (Linking)
VI  - 12
IP  - 2
DP  - 1996 Mar-Apr
TI  - Growth and induction kinetics of inducible and autoinducible expression of 
      heterologous protein in suspension cultures of recombinant mouse L cell lines.
PG  - 226-33
AB  - Mouse Ltk- cells were transfected with four different plasmids for autoinducible 
      and highly-inducible expression of the bacterial lacZ gene and cultivated in 
      suspension. Two selection genes, thymidine kinase (tk) and neomycin resistance 
      (neor), were used to select the clones in both cell lines. The resulting two cell 
      lines, designated M4 and R2, differ in that the inducible MMTV promoter from 
      mouse mammary tumor virus (MMTV) controls glucocorticoid receptor (gr) gene and 
      lacZ gene expression in the M4 cell line ("autoinducible"), while the 
      constitutive rous sarcoma virus (RSV) promoter controls gr gene expression and 
      the MMTV promoter controls lacZ gene expression in the R2 cell line 
      ("highly-inducible"). Both cell lines were stable with respect to reproducibility 
      of growth rate in spinner flasks and inducibility of beta-galactosidase 
      expression. The exponential growth rate of R2 cells was slower than that of M4 
      cells before induction because the R2 cell line continuously expressed gr genes 
      under the constitutive RSV promoter, and the percent reduction of exponential 
      growth rate mainly caused by gr gene expression was about 20%. The inducibility 
      of the M4 cell line was greater than that of the R2 cell line because in the M4 
      cell line MMTV promoter controlled gr and lacZ gene expression autoinducibly. 
      Maximum induction of the M4 cell line occurred after induction with the hormone 
      dexamethasone (Dex) at 10(-7) M, and the final beta-galactosidase content 
      increased 400-fold after induction. The optimum conditions for inducer 
      concentration and induction time were determined, and the highest production of 
      beta-galactosidase occurred when Dex was added after the cell concentration had 
      reached its maximum in batch culture. Dex (10(-9) M) is a critical inducer 
      concentration in view of inducibility between M4 and R2 cell lines. The 
      inducibility of R2 cell line is higher than that of the M4 cell line from 0 to 
      10(-9) M Dex, but the inducibility of M4 was higher than that of the R2 cell line 
      at Dex concentrations of more than 10(-9) M.
FAU - Gu, M B
AU  - Gu MB
AD  - Department of Chemical Engineering, University of Colorado, Boulder 80309-0424, 
      USA.
FAU - Todd, P
AU  - Todd P
FAU - Kompala, D S
AU  - Kompala DS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Biotechnol Prog
JT  - Biotechnology progress
JID - 8506292
RN  - 0 (Receptors, Glucocorticoid)
RN  - 0 (Recombinant Proteins)
RN  - 0 (Suspensions)
RN  - 7S5I7G3JQL (Dexamethasone)
RN  - EC 3.2.1.23 (beta-Galactosidase)
MH  - Animals
MH  - Dexamethasone/pharmacology
MH  - Gene Expression
MH  - L Cells/*metabolism
MH  - Mice
MH  - Receptors, Glucocorticoid/biosynthesis/genetics
MH  - Recombinant Proteins/*biosynthesis
MH  - Suspensions
MH  - beta-Galactosidase/biosynthesis
EDAT- 1996/03/01 00:00
MHDA- 1996/03/01 00:01
CRDT- 1996/03/01 00:00
PHST- 1996/03/01 00:00 [pubmed]
PHST- 1996/03/01 00:01 [medline]
PHST- 1996/03/01 00:00 [entrez]
AID - bp950074s [pii]
AID - 10.1021/bp950074s [doi]
PST - ppublish
SO  - Biotechnol Prog. 1996 Mar-Apr;12(2):226-33. doi: 10.1021/bp950074s.