scholarly journals Transcriptional activation of cathepsin D gene expression by growth factors

2000 ◽  
Vol 24 (2) ◽  
pp. 193-202 ◽  
Author(s):  
F Wang ◽  
R Duan ◽  
J Chirgwin ◽  
SH Safe
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Reporter Gene ◽  
Cathepsin D ◽  
Mapk Pathway ◽  
Gene Promoter ◽  
Gene Activity ◽  
Reporter Gene Activity ◽  
Igf I ◽  
Mcf 7

Insulin-like growth factor-I (IGF-I), transforming growth factor alpha (TGFalpha) and epidermal growth factor (EGF) induced cathepsin D gene expression and reporter gene activity in MCF-7 human breast cancer cells transiently transfected with a construct (pCD1) containing a -2576 to -124 cathepsin D gene promoter insert. In contrast, IGF-I, but not TGFalpha or EGF, induced reporter gene activity in cells cotransfected with wild-type estrogen receptor (ER) expression plasmid and a construct (pCD2) containing estrogen-responsive downstream elements from -208 to -101. Promoter deletion and mutational analysis experiments identified four GC-rich sites and an imperfect palindromic estrogen responsive element required for IGF-I activation of the ER (ligand-independent). Subsequent studies with the mitogen-activated protein kinase (MAPK) inhibitor, PD98059, and a serine(118(-ER mutant confirmed the role of the MAPK pathway for IGF-I activation of the ER in MCF-7 cells. Thus, growth factor activation of ER can mediate transactivation vs ER/Sp1 binding to GC-rich sites and represents a novel pathway for ligand-independent ER action. The divergent pathways for IGF-I and TGFalpha/EGF activation of the ER observed in MCF-7 cells contrast with previous data indicating that pathways for growth factor activation of the ER are dependent on the gene and/or gene promoter and on cell context.

Analysis of Gene Expression in Streptococcus Mutans in Biofilms in Vitro

1997 ◽  
Vol 11 (1) ◽  
pp. 100-109 ◽  
Author(s):  
Robert A. Burne ◽  
Yi-Ywan M. Chen ◽  
Jana E.C. Penders
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Regulation Of Gene Expression ◽  
Gene Promoter ◽  
Gene Activity ◽  
Gene Fusions ◽  
Promoter Regions ◽  
Environmental Signals ◽  
Reporter Gene Activity

The purpose of this study was to develop methods for the consistent production of biofilms of S. mutans containing reporter gene fusions, and to examine the expression of genes involved in sucrose metabolism in adherent populations of this organism. Three strains of S. mutans harboring reporter gene fusions to the gene promoter regions of the gtfBC genes, ftf, and scrA were grown in a Rototorque biofilm fermenter in a tryptone-yeast extract-sucrose medium. Quasi-steady-state levels of reporter gene activity were measured after the biofilms were grown for either 48 hrs or 7 days. Also, induction of gene expression by the addition of sucrose to biofilm cells was monitored. Reporter gene activity was measurable from all gene fusion strains. This study (i) establishes the feasibility of doing detailed molecular and physiologic studies on immobilized populations of S. mutans, (ii) demonstrates that the polysaccharide synthesis machinery of S. mutans is differentially expressed in biofilms, and (iii) opens the way for a more detailed analysis of the environmental signals and signal transduction pathways governing the regulation of gene expression by S. mutans cells that are immobilized on a solid surface.

scholarly journals Inhibition of cellular proliferation by the Wilms' tumor suppressor WT1 is associated with suppression of insulin-like growth factor I receptor gene expression.

1995 ◽  
Vol 15 (7) ◽  
pp. 3516-3522 ◽  
Author(s):  
H Werner ◽  
Z Shen-Orr ◽  
F J Rauscher ◽  
J F Morris ◽  
C T Roberts ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Tumor Suppressor ◽  
Cell Line ◽  
Cellular Proliferation ◽  
Wilms Tumor ◽  
Gene Promoter ◽  
R Gene ◽  
Factor I ◽  
Igf I

We have investigated the regulation of the insulin-like growth factor I receptor (IGF-I-R) gene promoter by the Wilms' tumor suppressor WT1 in intact cells. The levels of endogenous IGF-I-R mRNA and the activity of IGF-I-R gene promoter fragments in luciferase reporter constructs were found to be significantly higher in G401 cells (a Wilms' tumor-derived cell line lacking detectable WT1 mRNA) than in 293 cells (a human embryonic kidney cell line which expresses significant levels of WT1 mRNA). To study whether WT1 could suppress the expression of the endogenous IGF-I-R gene, WT1-negative G401 cells were stably transfected with a WT1 expression vector. Expression of WT1 mRNA in G401 cells resulted in a significant decrease in the rate of cellular proliferation, which was associated with a reduction in the levels of IGF-I-R mRNA, promoter activity, and ligand binding and with a reduction in IGF-I-stimulated cellular proliferation, thymidine incorporation, and anchorage-independent growth. These data suggest that a major aspect of the action of the WT1 tumor suppressor is the repression of IGF-I-R gene expression.

scholarly journals Transcriptional Activation of Insulin-Like Growth Factor-Binding Protein-4 by 17β-Estradiol in MCF-7 Cells: Role of Estrogen Receptor-Sp1 Complexes*

Endocrinology ◽  
1999 ◽  
Vol 140 (6) ◽  
pp. 2501-2508 ◽  
Author(s):  
Chunhua Qin ◽  
Pomila Singh ◽  
Stephen Safe
Keyword(s):  
Gene Expression ◽  
Estrogen Receptor ◽  
Growth Factor ◽  
Binding Protein ◽  
Gene Promoter ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Human Estrogen Receptor ◽  
17Β Estradiol ◽  
Mcf 7

Abstract Insulin-like growth factor-binding protein-4 (IGFBP-4) is expressed in MCF-7 human breast cancer cells, and treatment of these cells with 17β-estradiol (E2) resulted in induction of IGFBP-4 gene expression (>3-fold) and protein secretion (>6-fold). To identify genomic sequences associated with E2 responsiveness, the 5′-promoter region (−1214 to +18) of the IGFBP-4 gene was cloned into a vector upstream from the firefly luciferase reporter gene, and E2 induced a 10-fold increase in luciferase activity in MCF-7 cells transiently transfected with this construct. Deletion analysis of this region of the IGFBP-4 gene promoter identified two GC-rich sequences at −559 to −553 and −72 to −64 that were important for E2-induced trans-activation. Gel mobility shift assays using 32P-labeled −569 to −540 and −83 to −54 oligonucleotides from the IGFBP-4 gene promoter showed that Sp1 protein bound these oligonucleotides to form a retarded band, and the intensity of the band was competitively decreased after coincubation with unlabeled IGFBP-4-derived and consensus Sp1 oligonucleotides. Mutation of the GC-rich sites within these sequences resulted in loss of the retarded band formation. Wild-type human estrogen receptor did not bind directly to the IGFBP-4 oligonucleotides; however, human estrogen receptor enhanced Sp1-DNA binding in a concentration-dependent manner. The results of this study demonstrate that at least two GC-rich sequences at −559 to −553 and− 72 to −64 are required for induction of IGFBP-4 gene expression by E2 in MCF-7 cells.

Regulation of insulin-like growth factor-I gene expression by growth factors in cultured vascular smooth muscle cells

1990 ◽  
Vol 125 (3) ◽  
pp. 381-386 ◽  
Author(s):  
K. E. Bornfeldt ◽  
H. J. Arnqvist ◽  
G. Norstedt
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Basic Fgf ◽  
Aortic Smooth Muscle ◽  
Factor I ◽  
Igf I ◽  
I Gene

ABSTRACT The aim of this investigation was to study the regulation of insulin-like growth factor-I (IGF-I) gene expression in cultured rat aortic smooth muscle cells. Near-confluent cells were deprived of serum for 24 h and then exposed to IGF-I, insulin, serum, basic fibroblast growth factor (basic FGF), platelet-derived growth factor (PDGF-BB; consisting of B-chain homodimer) or GH for 24 h. Levels of IGF-I mRNA were measured by solution hybridization. The level of IGF-I mRNA was markedly decreased by 10% (v/v) newborn calf serum (78 ± 4 (s.e.m.) % decrease), 1 nmol basic FGF/1 (53 ± 8%), and 1 nmol PDGF-BB/1 (40 ± 3%) when measured after 24 h. The effect of PDGF-BB was significant after 6 h and became more marked after 24 h. GH (1 nmol/l or 0.1 μmol/l or insulin (1 nmol/l had no effect after 24 h, whereas IGF-I (1 nmol/l and insulin (10 μmol/l increased IGF-I mRNA 64 ± 20% and 46±14% respectively. The increase caused by IGF-I was demonstrated after 3 h, and was most marked after 24 h. Using Northern blot analysis of cultured aortic smooth muscle cells, IGF-I transcripts of 7-4, 1.7 and 1.1–0.8 kilobases were observed. Exposure of the cells to 10% serum, 1 nmol basic FGF/1 or 1 nmol PDGF-BB/1 for 48 h increased the cell number by 104 ±7%, 64 ± 3% and 61±22% respectively, while IGF-I, insulin and GH had little effect. In conclusion, IGF-I, and high concentrations of insulin, increased IGF-I mRNA in vascular smooth muscle cells, whereas factors which were stronger mitogens decreased IGF-I gene expression. Journal of Endocrinology (1990) 125, 381–386

Cell type-specific requirement of the MAPK pathway for the growth factor action of gastrin

1999 ◽  
Vol 276 (6) ◽  
pp. G1363-G1372 ◽  
Author(s):  
Vinzenz M. Stepan ◽  
Chris J. Dickinson ◽  
John del Valle ◽  
Masashi Matsushima ◽  
Andrea Todisco
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Growth Factor ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Cell Type ◽  
Ar42j Cells ◽  
Cell Type Specific ◽  
Ar42j Cell ◽  
Stimulation Of

Gastrin (G17) has a CCKBreceptor-mediated growth-promoting effect on the AR42J rat acinar cell line that is linked to induction of both mitogen-activated protein kinase (MAPK) and c- fos gene expression. We investigated the mechanisms that regulate the growth factor action of G17 on the rat pituitary adenoma cell line GH3. Both AR42J and GH3cells displayed equal levels of CCKBreceptor expression and similar binding kinetics of125I-labeled G17. G17 stimulation of cell proliferation was identical in both cell lines. G17 stimulation of GH3cell proliferation was completely blocked by the CCKBreceptor antagonist D2 but not by the MEK inhibitor PD-98059 or the protein kinase C inhibitor GF-109203X, which completely inhibited G17 induction of AR42J cell proliferation. G17 induced a c- fos SRE-luciferase reporter gene plasmid more than fourfold in the AR42J cells, whereas it had no effect in the GH3cells. In contrast to what we observed in the AR42J cells, G17 failed to stimulate MAPK activation and Shc tyrosyl phosphorylation and association with the adapter protein Grb2. Epidermal growth factor induced the MAPK pathway in the GH3cells, demonstrating the integrity of this signaling system. G17 induced Ca2+mobilization in both the GH3and AR42J cells. The calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide inhibited AR42J cell proliferation by 20%, whereas it completely blocked G17 induction of GH3cell growth. The Ca2+ionophore ionomycin stimulated GH3cell proliferation to a level similar to that observed in response to G17, but it had no effect on AR42J cell proliferation. Thus there are cell type specific differences in the requirement of the MAPK pathway for the growth factor action of G17. Whereas in the AR42J cells G17 stimulates cell growth through activation of MAPK and c- fos gene expression, in the GH3cells, G17 fails to activate MAPK, and it induces cell proliferation through Ca2+-dependent signaling pathways. Furthermore, induction of Ca2+mobilization in the AR42J cells appears not to be sufficient to sustain cell proliferation.

Gene expression in skeletal muscle

2002 ◽  
Vol 30 (2) ◽  
pp. 285-290 ◽  
Author(s):  
G. Goldspink
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Molecular Motors ◽  
Mechanical Activity ◽  
Reading Frame ◽  
Metabolic Genes ◽  
Igf I ◽  
Systemic Factors ◽  
Repair Factor ◽  
Qualitative Changes

Muscle has an intrinsic ability to change its mass and phenotype in response to activity. This process involves quantitative and qualitative changes in gene expression, including that of the myosin heavy chain isogenes that encode different types of molecular motors. This, and the differential expression of metabolic genes, results in altered fatigue resistance and power output. The regulation of muscle mass involves autocrine as well as systemic factors. We have cloned the cDNAs of local and systemic isoforms of insulin-like growth factor-I (IGF-I) from exercised muscle. Although different isoforms are derived from the IGF-I gene by alternative splicing, the RNA transcript of one of them is only detectable following injury and/or mechanical activity. Thus this protein has been called mechano growth factor (MGF). Because of a reading-frame shift, MGF has a different 3′ sequence and a different mode of action compared with systemic or liver IGF-I. Although MGF has been called a growth factor, it may be regulated as a local repair factor.

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