Bellefleur

Curran, Ronald; Oates, Joyce Carol

doi:10.2307/40137017

Cited by 1 publication

(2 citation statements)

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“…We have previously shown that boiling of cell lysates in 0.5% NaDod-S04 prior to precipitation with M2 antiserum prevented precipitation of p39 and p37, suggesting that these proteins are complexed with fos proteins (34). Low amounts of the p39/37 were precipitated 16 hr after NGF addition, indicating that small amounts of fos proteins were present at later times (data not shown). It is possible that late after induction, the fos proteins are too heterogeneous, due to postsynthetic modification, to be detected by gel electrophoresis (20).…”

Section: P-labeled V-fos Probe (17)mentioning

confidence: 93%

“…A direct link between proto-oncogenes and cell-growth regulation was established when it was discovered that the proto-oncogne sis encodes the B chain ofplatelet-derived growth factor (PDGF) and erbB gene product is a truncated form of epidermal growth factor (EGF) receptor (10-13). We have been studying the proto-oncogenefos, whose viral cognate, v-fos, is the transforming gene of two murine retroviruses that induce osteosarcomas in vivo and transform fibroblasts in vitro (14)(15)(16)(17). The viral and cellular fos proteins differ at their COOH termini, but both are found in the nucleus and both induce transformation (18)(19)(20).…”

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confidence: 99%

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Induction of the proto-oncogene fos by nerve growth factor.

Kruijer¹,

Schubert²,

Verma³

1985

Proc. Natl. Acad. Sci. U.S.A.

310

172

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Nerve growth factor (NGF) causes the differentiation of PC12 cells to sympathetic neuron-like cells and also induces a rapid but transient expression of fos mRNA and protein. fos mRNA transcripts can be detected 5 min after the addition of NGF, are maximally abundant after 30 min, and then their levels decrease. fos protein synthesis parallels the expression of fos mRNA, and the induced fos proteins are located in the nucleus. cAMP, epidermal growth factor, the phorbol ester phorbol 12-myristate 13-acetate, and K+ depolarization also induce thefos gene. Growth of PC12 cells in the presence of dexamethasone, which induces differentiation into chromaffim-like cells, is not accompanied byfos expression. We propose that while fos gene induction is associated with the differentiation of PC12 cells to sympathetic nerve, its enhanced expression is primarily involved in the anabolic responses induced by NGF and many growth factors.It is the general consensus that proto-oncogenes are involved in the regulation of cell growth and differentiation (1-3). They are conserved during evolution and expressed in a tissue-and stage-specific manner during development (3-5). The expression of some proto-oncogenes is induced when resting cells proliferate in response to mitogens (6)(7)(8)(9). A direct link between proto-oncogenes and cell-growth regulation was established when it was discovered that the proto-oncogne sis encodes the B chain ofplatelet-derived growth factor (PDGF) and erbB gene product is a truncated form of epidermal growth factor (EGF) receptor (10-13). We have been studying the proto-oncogenefos, whose viral cognate, v-fos, is the transforming gene of two murine retroviruses that induce osteosarcomas in vivo and transform fibroblasts in vitro (14)(15)(16)(17). The viral and cellular fos proteins differ at their COOH termini, but both are found in the nucleus and both induce transformation (18)(19)(20). Finally, the expression offos is inducible in response to mitogens and certain differentiation-specific agents (21-23).To investigate further the role of fos gene in growth and differentiation, we have studied its induction by nerve growth factor (NGF) in the clonal rat pheochromocytoma cell line, PC12. In the presence of NGF, PC12 cells acquire properties of sympathetic neurons, including neurite outgrowth (24), increased electric excitability (25), and changes in neurotransmitter synthesis (26). NGF may also act as a weak mitogen in these cells (27). In contrast to the effect of NGF, when PC12 cells are grown in the presence of dexamethasone, they acquire the characteristics of chromaffin cells (28). We report here that the fos gene is rapidly and transiently expressed when NGF is added to PC12 cells, but no expression ofthefos gene is detected in PC12 cells upon the addition of dexamethasone. MATERIALS AND METHODSPC12 cells were grown in Dulbecco's modified Eagle's medium containing 10% fetal calf serum and 5% horse serum as described (28). For induction, the culture medium was aspirated and replaced by N2...

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Section: P-labeled V-fos Probe (17)mentioning

confidence: 93%

mentioning

confidence: 99%