Isolation and oncogenic potential of a novel human src-like gene.

Abstract

We have isolated cDNA molecules representing the complete coding sequence of a new human gene which is a member of the src family of oncogenes. Nucleotide sequence analysis revealed that this gene, termed slk, encoded a 537-residue protein which was 86% identical to the chicken proto-oncogene product, p60CSrc, over a stretch of 191 amino acids at its carboxy terminus. In contrast, only 6% amino acid homology was observed within the amino-terminal 82 amino acid residues of these two proteins. It was possible to activate slk as a transforming gene by substituting approximately two-thirds of the slk coding sequence for an analogous region of the v-fgr onc gene present in Gardner-Rasheed feline sarcoma virus. The resulting hybrid protein molecule expressed in transformed cells demonstrated protein kinase activity with specificity for tyrosine residues.Normal cellular genes which have given rise to retrovirus onc sequences represent the most abundant class of genes capable of acquiring oncogenic properties. In addition to these, dominant transforming genes present in certain tumor cells have been found by their ability to induce foci of transformation when transfected into susceptible assay cells (for a review, see reference 1). More recently, other genes implicated in the malignant process by virtue of their amplification in tumor cells have been identified because of their genetic relatedness to known oncogenes (15,17,32). Of the transforming genes identified to date, roughly half encode products which possess structural or enzymatic relatedness to protein-tyrosine kinases. This family includes altered versions of genes encoding cell surface receptors for certain growth factors (8,35,40), as well as a much larger number that have not yet been linked to normal cellular functions.The prototype protein-tyrosine kinase gene v-src (6) and its close relatives, v-yes (16) and v-fgr (23), were each identified initially within oncogenic retroviruses as components derived from distinct cellular genes (38). In an effort to search for new src-related genes within the human genome, we have taken a more general approach not reliant upon the identification of novel oncogenic viruses or transforming genes, but dependent only upon normal gene expression. In the present study, we report the isolation of cDNA molecules representing the complete coding sequence of a new human src-related gene and demonstrate that the gene can acquire transforming properties by substituting a portion of its coding sequence for a related onc gene in a retrovirus vector. New England Nuclear Corp.) per ml or with 4 ml methionine-free Dulbecco modified Eagle medium containing 125 ,uCi of [35S]methionine (New England Nuclear) per ml. Radiolabeled cells were lysed with 1 ml of lysing buffer (10 mM sodium phosphate [pH 7.5], 100 mM NaCl, 1% Triton X-100, 0.5% sodium deoxycholate, and 0.1 mM phenylmethylsulfonyl fluoride) per petri dish, clarified by centrifugation at 100,000 x g for 30 min, and divided into five identical aliquots. Extracts were incubated wi...

Calcium dependent activation of the NF‐AT transcription factor by p59fyn

“…The protein tyrosine kinase p59fyn [7,8] is found physically associated with the intracellular domain of the TCR complex and is therefore likely to be involved in TCR signal transduction [9]. Several lines of evidence support this view.…”

Identification of a human gene (HCK) that encodes a protein-tyrosine kinase and is expressed in hemopoietic cells.

“…3; Table 2). (19,50), c-src (55), and c-yes (20,51). it to membranes (7, 41, The exceptional similarities among the nucleotide sequences 42).…”

Tyrosine phosphorylation of a c-Src-like protein is increased in membranes of CD4- CD8- T lymphocytes from lpr/lpr mice.

“…quenced by two groups (32,53). To confirm this supposition, we concentrated on the two unique features of the p60 whose phosphorylation was increased in lpr cells: (i) the pI of pH -6.3 to 6.5 and (ii) the distinct Staph V8 cleavage map.…”