ISOLATION AND CHARACTERIZATION OF THE HUMAN DTK RECEPTOR TYROSINE KINASE

A cDNA encoding the human homologue of the murine DTK receptor tyrosin e kinase has been isolated from a human brain library. The DTK cDNA en codes a mature protein of 850 amino acids with similar structural feat ures to those of the murine receptor. The extracellular domain contain s two immunoglobulin-like motifs and two fibronectin type III modules; features which define a new class of receptor tyrosine kinase. The hu man DTK gene has been mapped by fluorescent in situ hybridization to c hromosome 15q15, and a DTK-related gene identified at chromosome 15q24 . In fetal tissues, transcripts for DTK were detected in brain, kidney , lung and heart. Prominent expression was observed in the embryonal c arcinoma cell line NT2/D1. Expression of the gene is up-regulated in a dult tissues with high levels of expression in many regions of the adu lt brain. DTK is also abundantly expressed in adult kidney, testis, an d ovary.