title: Additional member of the protein-tyrosine kinase family: the src- and lck-related protooncogene c-tkl.
abstract: We report the isolation and nucleotide sequence of a 3.7-kilobase (kb) cDNA clone from chicken spleen corresponding to a previously undescribed member of the src family of protooncogenes. It encodes a protein with a C-terminal domain related to the src family of protein-tyrosine kinases (EC 2.7.1.112) and, among these, has most significant homology to the lck gene isolated from a murine leukemia virus-induced thymoma cell line. The gene is therefore referred to as c-tkl for cellular tyrosine kinase related to lck. Analysis of genomic DNA reveals that c-tkl is a chromosomal locus distinct from c-src and c-lck. Furthermore, the size of c-tkl mRNA as well as its pattern of expression indicates that it is not the chicken homologue of lck but a different gene. A 3.8-kb transcript of the c-tkl gene, identical to the size determined for c-src mRNA, was observed in cultured chicken embryo fibroblasts and in chicken spleen and brain. In contrast, detection of a definite c-src mRNA signal with mRNA from spleen was not possible under the hybridization conditions employed when the 5' end of v-src was used as the probe, and none of the 11 clones obtained from the cDNA library corresponded to a c-src transcript. Thus previous studies of c-src mRNA expression in spleen may have actually detected c-tkl transcripts.
authors.affiliation: Chemotherapeutisches Forschungsinstitut, Georg-Speyer-Haus, Frankfurt, Federal Republic of Germany.
authors.forename: K
authors.initials: K
authors.lastname: Strebhardt
authors.forename: J I
authors.initials: JI
authors.lastname: Mullins
authors.forename: C
authors.initials: C
authors.lastname: Bruck
authors.forename: H
authors.initials: H
authors.lastname: Rübsamen-Waigmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002645:Chickens / Q000235:genetics*; D003001:Cloning, Molecular; D005796:Genes; D008969:Molecular Sequence Data; D005810:Multigene Family; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D014018:Tissue Distribution
chemical_list: D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases