GTPγS inhibits early c‐myc protein accumulation but not DNA synthesis in Swiss 3T3 fibroblasts

FEBS Letters

Metcalfe, James C.¹  Pennington, Stephen R.¹  Moore, John P.¹  Evan, Gérard I.¹  Hesketh, T.Robin¹ 

[1]Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 IQW, UK

关键词: GTPγS;    c-myc Protein;    DNA synthesis;    3T3 fibroblast;    Transient permeabilisation;    GTPγS;    guanosine 5'-O-(3-thiotriphosphate);    EGF;    epidermal growth factor;    DMEM;    Dulbecco's modified Eagle's medium;    FCS;    foetal calf serum;    TCA;    trichloroacetic acid;    SDS;    sodium dodecyl sulfate;   

DOI  :  10.1016/0014-5793(90)81095-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Quiescent Swiss 3T3 fibroblasts stimulated with epidermal growth factor and insulin showed large transient increases in c-myc mRNA and c-myc protein accumulation which were maximal at about 2 h after addition of the co-mitogens. When the cells were loaded with 0.1 mM of guanosine 5'-O-(3-thiotriphosphate) (GTPγS) by transient permeabilisation immediately before mitogenic stimulation, the increase in c-myc mRNA was similar to that observed in unloaded cells but the corresponding c-myc protein peak was reduced by at least 95%. The GTPγS completely blocked incorporation of [³⁵S]methionine into cell proteins for 3–4 h after addition of the mitogens, but not thereafter, and caused a delay in the subsequent onset of DNA synthesis by the same period. The data show that less than 5% of the early increase in c-myc protein normally observed after mitogenic stimulation is required for its obligatory role in the progression of cells to S phase implied by other evidence.

【 授权许可】

Unknown