Additional Member of the Protein-Tyrosine Kinase Family: The src- and lck-Related Protooncogene c-tkl

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 84; no. 24; pp. 8778 - 8782
• Main Authors: Strebhardt, Klaus, Mullins, James I., Bruck, Claudine, Rübsamen-Waigmann, Helga
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.12.1987; National Acad Sciences
• Subjects: Amino Acid Sequence; Amino acids; Analytical, structural and metabolic biochemistry; Animals; Base Sequence; Biological and medical sciences; Cells, Cultured; Chickens; Chickens - genetics; Cloning, Molecular; Complementary DNA; DNA; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Generally accepted auditing standards; Genes; Messenger RNA; Molecular Sequence Data; Multigene Family; Nucleotides; Protein-Tyrosine Kinases - genetics; Proto-Oncogene Proteins - genetics; RNA; RNA, Messenger - genetics; Spleen; Tissue Distribution; Transferases; Characterization; Spleen; Vertebrata; Animal; C-Onc gene; Primary structure; Identification; Chicken; Aves; Molecular cloning; Protein-tyrosine kinase
• DOI: 10.1073/pnas.84.24.8778
• ISSN: 0027-8424

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.