The cytokine receptor repertoire specifies autocrine growth factor production in factor-dependent cells.
Mechanisms of helper virus-induced growth factor-independence were examined in FDC-P1 cells and FDC-P1 cells expressing the erythropoietin receptor (FDER cells). Retroviral mutagenesis of FDC-P1 cells led to factor-independent (FI) colonies from which cell lines could readily be established; whereas control cells exhibited at least 20 to 40-fold lower rates of factor-independence. From 44 independent experiments using either FDC-P1 or FDER cells, 205 autonomous cell lines were obtained. Sixteen colonies displayed a novel ("satellite-inducing") appearance in agar and produced up to 4.1 x 10(5) U/mL granulocyte-macrophage colony-stimulating factor (GM-CSF) (some with altered GM-CSF transcript sizes) and/or interleukin-3 (IL-3). Retroviral mutagenesis of FDER cells increased the repertoire of autocrine growth factors now responsible for stimulating autocrine proliferation: 3% of FI cell lines produced erythropoietin (Epo) (0.5 U/mL). Unexpectedly, in every autonomous FDC-P1 cell line, reverse transcriptase-PCR demonstrated expression of a growth factor normally required for proliferation. Thus, a profound selection for cells able to produce growth factors as the mechanism for achieving autonomous proliferation was documented. The ectopic expression of a receptor lacking a cognate ligand ("orphan") followed by retroviral mutagenesis and selection for autocrine mutants may offer an effective method for identifying new ligands.
Rasko
J E
JE
Walter and Eliza Hall Institute of Medical Research, Victoria, Australia.
Metcalf
D
D
Gough
N M
NM
Begley
C G
CG
D000818:Animals; D017660:Autoreceptors / Q000502:physiology*; D002455:Cell Division / Q000235:genetics; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral / Q000235:genetics*; D002999:Clone Cells; D004921:Erythropoietin / Q000096:biosynthesis / Q000235:genetics; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology*; D006378:Helper Viruses / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000502:physiology*; D007377:Interleukin-3 / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology*; D051379:Mice; D008979:Moloney murine leukemia virus / Q000502:physiology; D016296:Mutagenesis; D016133:Polymerase Chain Reaction; D017978:Receptors, Growth Factor / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology
D017660:Autoreceptors; D007377:Interleukin-3; D017978:Receptors, Growth Factor; D011994:Recombinant Proteins; D004921:Erythropoietin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor