Cloning and sequencing of the cDNA for thecphoncogene from neoplastic hamster fibroblasts reveal partial homology with thedblexchange factor

摘要

AbstractThe combination of in vitro transformation protocols and transfection assays allowed us to isolate a new transforming gene,cph, from neoplastic Syrian hamster embryo fibroblasts chemically initiated with a single dose of 3‐methylcholanthrene. Cosmid clones encompassingcphgenomic sequences were able to transform NIH/3T3 cells and showed a synergistic action with H‐rasin the transformation of the murine fibroblasts. In the present study, we describe the molecular cloning of the hamstercphoncogene cDNA. Nucleotide sequence analysis of a full‐length cDNA clone (pBl‐19), isolated from a cDNA library from neoplastic hamster cells withcphgenomic probes demonstrated that the clonedcphcDNA does not show any significant global homology to sequences deposited in established databases, confirming thatcphis a novel gene. ThecphcDNA contained an open reading frame with coding capacity for a protein of about 26 kDa, which was synthesized from pBl‐19 by using in vitro transcription‐translation assays. The cph protein deduced from the cDNA nucleotide sequence contained a dbl‐homologous (DH) domain. The fact that the DH domain has been found primarily among GDP‐exchange factors suggests that cph may be a new member of this family of proteins. © 1995