The c-sis gene encodes a precursor of the B chain of platelet-derived growth factor.

Abstract

The relationship between platelet‐derived growth factor (PDGF) and the proto‐oncogene c‐sis has been determined by amino acid sequence analysis of PDGF and nucleotide sequence analysis of c‐sis genomic clones. The nucleotide sequences of five regions of the human c‐sis gene which are homologous to sequences of the transforming region (v‐sis) of simian sarcoma virus (SSV) were determined. By alignment of the c‐sis and v‐sis nucleotide sequences the predicted amino acid sequence of a polypeptide homologous to the putative transforming protein p28sis of SSV was deduced. Both predicted sequences use the same termination codon and additional coding sequences may lie 5′ to the homologous regions. Amino acid sequence analysis of the PDGF B chain shows identity to the amino acid sequence predicted from the c‐sis sequences over 109 amino acid residues. Polymorphism may exist at two amino acid residues. These results suggest that c‐sis encodes a polypeptide precursor of the B chain. A partial amino acid sequence of the PDGF A chain is also described. This chain is 60% homologous to the B chain and cannot be encoded by that part of c‐sis which has been sequenced but could be encoded by sequences which lie 5′ to the five regions of v‐sis homology in c‐sis, or at a separate locus.

Platelet-derived growth factor and vascular endothelial growth factor expression in disc herniation tissue: an immunohistochemical study

“…It appears either in the form of an A-A or a B-B homodimer or as an A-B heterodimer [15]. It stimulates the growth of vascular endothelial cells [26] and fibroblasts [29].…”

Specific cleavage of the fibroblast receptor for platelet‐derived growth factor by an endogenous Ca2+‐dependent thiol protease

“…Pure PDGF was prepared as described [30] and EGF was purchased from Collaborative Research. Iodoacetamide, phenylmethylsulfonyl fluoride (PhMeS02F) and sodium-ATP were from Sigma, and staphyloccocal V 8 protease was from Miles Laboratories.…”

“…Briefly, 10 pg membranes were incubated at 0°C in 20 mM Hepes pH 7.4, 0.06 M NaCl, 1 mg/ml bovine serum albumin, 3 mM MnC12, 10 pM [32P]ATP (2.3 pCi radioactivity) with or without 75 nM PDGF, in a final volume of 40 pl. 30 rnin after the addition of PDGF the reaction was initiated by the addition of [32P]ATP; the reaction was stopped after another 10 min by adding 40 p1 sodium dodecyl sulphate (SDS)-containing sample buffer (80 mM Tris/HCl, pH 8.8, 3.6% SDS, 10 mM dithiothreitol and 0.01% bromophenol blue) and heating at 95 "C for 3 min.…”

Effect of the different dimeric forms of the platelet‐derived growth factor on cellular responses in mouse Swiss 3T3 fibroblasts

“…The A and B subunits share 60°70 homology and the B chain is the product of the c-sis gene, the normal counterpart of the v-sis oncogene carried by the simian sarcoma virus [3]. All three possible dimeric forms of PDGF have been isolated from different sources: PDGF purified from human platelets (hPDGF) mainly consists of the AB heterodimer [4], porcine PDGF (pPDGF) is a BB homodimer [5], as is the transforming product of the simian sarcoma virus.…”