ISSN:
0730-2312
Keywords:
PDGF A
;
PDGF B
;
BHK cells
;
gene transfection
;
growth selection
;
foreign genes
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
The genes for platelet-derived growth factor (PDGF) A and PDGF B chains are expressed in a variety of biological situations. Active PDGF consists of two distinct but homologous polypeptide chains, PDGF A and PDGF B, which are found as heterodimers or homodimers. We report a novel situation in which there is selective expression of mRNA encoding PDGF B in cell lines derived from baby hamster kidney (BHK) following transfection with various gene/cDNA constructs and following growth selection with methotrexate. The process of transfection itself, and not expression of the proteins encoded by the transfected genes/cDNAs (hormones, enzymes, and structural proteins), induces expression of PDGF B. No PDGF B mRNA is detectable in control cell lines. Low levels of mRNA encoding PDGF A are constitutively present and are not changed by transfection and/or growth selection. PDGF-like activity is present in the medium whenever PDGF B mRNA is detected. The composition of the secreted PDGF dimer cannot be established from our data, but quantitative analysis of mRNA suggests that the PDGF is a B-B dimer. However, the data show that transcription of the PDGF A and PDGF B genes in BHK cells is regulated independently, similar to that reported for some human tumor cells. Furthermore, the selective expression of PDGF B in response to the introduction of foreign genes and to growth selection may be an important aspect of the reaction of these cells to nonoptimal growth conditions, allowing survival and growth of the cells that express PDGF B.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcb.240390110
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