Abstract
We have isolated cDNA clones from a mouse embryonic head cDNA library that encode one member of the Eph/Eck family of receptor tyrosine kinases (RTKs), Ebk/MDKl. Among the 10 clones, two showed full-length type comprising extracellular, transmembrane and intracellular kinase domains. Two of them were modified just after the transmembrane domain and stop codon appeared before completing the kinase domain. This truncated form also had a deletion of five amino acids at the extracellular domain, indicating that it is a novel variant of Ebk/MDKl. RNase protection assay showed that this truncated deleted type, named Ebk-tdl, is present in the head of embryos, although the amount is less compared to that of the full-length type having a deletion of four amino acids. Considering the source and expression of Ebk/MDKl mRNAs, they may have an important role, accompanied with a possible regulatory role of the truncated variant, during neural development and/or in embryogenesis.
