brt, a mouse gene encoding a novel receptor-type protein-tyrosine kinase, is preferentially expressed in the brain

Using polymerase chain reaction (PCR)-mediated cloning procedure, we have isolated a novel gene encoding protein-tyrosine kinase from fetal mouse brain. This gene, named brt (from brain tyrosine kinase), had an open reading frame that encoded 856 amino acids. The deduced amino acid sequence revealed that the gene product had all the hallmarks of a receptor-type protein-tyrosine kinase. The brt protein showed significant homology to the axl/ufo protein that has an oncogenic potential. Northern blot analysis showed that brt was expressed preferentially in the brain of both embryo and adult. Thus, brt is a new member of the subfamily of receptor-type protein-tyrosine kinases and is suggested to play important roles in development and functions in the central nervous system.