SUPPRESSION OF PLATELET-DERIVED GROWTH-FACTOR ALPHA-RECEPTOR AND BETA-RECEPTOR MESSENGER-RNA LEVELS IN HUMAN FIBROBLASTS BY SV40 T T ANTIGEN/

It is known that down-regulation of cell surface platelet-derived grow th factor (PDGF) receptors accompanies transformation by SV40. In this work human embryonic lung fibroblasts were used as a model system to study the effects of SV 40 on PDGF receptor expression. It is shown th at transformation by SV 40 early region leads to a total loss of PDGF alpha-receptor and partial loss of beta-receptor mRNA. Microinjection experiments revealed that receptor down-regulation was a primary effec t, and not only secondary to transformation and clonal selection. Tota l loss of PDGF alpha-receptor expression requires both large T and sma ll t, and down-regulation of the PDGF alpha-receptor occurs independen tly of p53 and Rb binding to large T. (C) 1996 Wiley-Liss, Inc.