Complex expression pattern of the CEF-4 cytokine in transformed and mitogenically stimulated cells.
The transformation of chicken embryo fibroblasts (CEF) by the Rous sarcoma virus leads to the constitutive expression of the cellular gene designated CEF-4. With specific antisera, we confirmed that transformed cells actively synthesize and secrete a 6 kDa polypeptide corresponding to the CEF-4 gene product. The expression of CEF-4 was investigated by Northern and immunoprecipitation analyses. Upon activation of pp60v-src in cells infected by a ts mutant of RSV, the expression of CEF-4 was biphasic with an early transient and a late constitutive period of expression. CEF-4 was expressed in cells transformed by a variety of oncogenes, but the level of constitutive expression differed quantitatively among transformed cells. Cells transformed by v-myc alone did not express CEF-4. Unlike other members of the interleukin 8 gene family, CEF-4 was induced in response to a broad spectrum of growth factors and inflammatory agents. Dexamethasone repressed the induction of CEF-4 by lipopolysaccharides but had little or no effect on the response to serum or pp60v-src. These data emphasize the complexity of CEF-4 expression and suggest the existence of multiple levels or pathways of CEF-4 regulation in normal and transformed cells.
Gonneville
L
L
Département de Biochimie, Université de Montréal, Québec, Canada.
Martins
T J
TJ
Bédard
P A
PA
D000818:Animals; D030161:Avian Proteins; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D002472:Cell Transformation, Viral / Q000235:genetics*; D002642:Chick Embryo; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics*; D008070:Lipopolysaccharides; D008938:Mitosis / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism*; D011817:Rabbits; D016192:Resting Phase, Cell Cycle; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D030161:Avian Proteins; D016207:Cytokines; C071280:EMF-1 protein, Gallus gallus; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta