Reduction in platelet-derived growth factor receptor mRNA in v-src-transformed fibroblasts.
The status of the platelet-derived growth factor (PDGF) receptor in normal rat kidney (NRK) fibroblasts and in NRK fibroblasts transformed by the v-src oncogene or the polyoma middle T (pmt) antigen has been compared. v-src-NRK cells have 7-fold fewer surface binding sites for PDGF than NRK cells, but the affinity of the residual receptors for PDGF is reduced only 2-fold. Levels of the PDGF receptor measured by Western blotting or in an autophosphorylation assay in vitro are 8- and 4-fold lower respectively in v-src-NRK cells than in NRK cells. No PDGF-induced phosphorylation of the PDGF receptor is apparent after 32P-labelling of intact v-src-NRK cells, implying that the reduction in PDGF receptor levels is not a consequence of production of autocrine PDGF. A 10-fold reduction in the amount of mRNA for the PDGF receptor is also observed in v-src-NRK cells. No decrease in PDGF receptor protein or mRNA levels is observed in pmt-NRK cells. We conclude that levels of the PDGF receptor in v-src-transformed NRK fibroblasts are modulated by reduction in the level of PDGF receptor mRNA.
Zhang
Q X
QX
Ludwig Institute for Cancer Research, Melbourne Tumour Biology, Royal Melbourne Hospital, Vic., Australia.
Walker
F
F
Burgess
A W
AW
Baldwin
G S
GS
D000818:Animals; D002461:Cell Line, Transformed; D015536:Down-Regulation; D009857:Oncogenes; D010766:Phosphorylation; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017479:Receptors, Platelet-Derived Growth Factor / Q000235:genetics* / Q000378:metabolism
D012333:RNA, Messenger; D017479:Receptors, Platelet-Derived Growth Factor