ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Much controversy regarding the relationship between nutrients and serum in regulation of cell growth can be reconciled by recognizing that serum contains multiple factors which regulate different events in the cell cycle. Serum was fractioned into a platelet-derived growth factor (PDGF), which induces cells to become competent to synthesize DNA, and plasma which allows competent cells to traverse G0/G1 and enter the S phase. Nutrients are not required for the cellular response to PDGF; however amino acids are required for plasma to promote the entry of PDGF-treated, competent cells into S phase. The nutrient independent, PDGF-modulated, growth regulatory event (competence) is located 12 hours prior to the G1/S phase boundary in quiescent, density-arrested Balb/c-3T3 cells. The nutrient dependent, plasma-modulated event is located six hours prior to the G1/S phase boundary and corresponds in time to a plasma dependent growth arrest point. Moreover, plasma controls the concentration of amino acids required for DNA synthesis. Infection of density-arrested Balb/c-3T3 cells with SV40 overrides both the nutrient independent and the nutrient dependent growth regulatory events.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1040990314
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