Developmental regulation of a murine T-cell-specific tyrosine kinase gene, Tsk.
Protein-tyrosine kinases have been implicated in signal transduction in T lymphocytes after stimulation of many cell-surface molecules, including the T-cell antigen receptor, CD4, CD8, CD2, CD5, and CD28. Yet the identities of many of these tyrosine kinases remain unknown. We have isolated a murine tyrosine kinase gene, called Tsk for T-cell-specific kinase, that appears to be exclusively expressed in T lymphocytes. The Tsk cDNA clone encodes a polypeptide of 70 kDa, which is similar in sequence to both the src and abl families of tyrosine kinases. Sequence comparisons also indicate that Tsk contains one src-homology region 2 domain and one src-homology 3 domain but lacks the negative regulatory tyrosine (src Tyr-527) common to src-family kinases. In addition, Tsk expression is developmentally regulated. Steady-state Tsk mRNA levels are 5- to 10-fold higher in thymocytes than in peripheral T cells and increase in the thymus during mouse development from neonate to adult. Furthermore, Tsk is expressed in day 14 fetal thymus, suggesting a role for Tsk in early T-lymphocyte differentiation.
Heyeck
S D
SD
Department of Cellular and Developmental Biology, Harvard University, Cambridge, MA 02138.
Berg
L J
LJ
D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology*; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D016313:Genes, abl / Q000235:genetics; D016391:Genes, src / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016133:Polymerase Chain Reaction; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000201:enzymology*; D013950:Thymus Gland; D014018:Tissue Distribution
D011505:Protein-Tyrosine Kinases