THE DROSOPHILA LEARNING AND MEMORY GENE LINOTTE ENCODES A PUTATIVE RECEPTOR TYROSINE KINASE HOMOLOGOUS TO THE HUMAN RYK GENE-PRODUCT

The linotte mutant was isolated on the basis of its learning and memor y deficit, Interestingly, linotte individuals carrying a null mutation are viable, indicating that the linotte gene is not required for vita l functions, We show here that the linotte gene encodes a putative rec eptor tyrosine kinase, homologous to the human protein RYK, These prod ucts are unique among receptor tyrosine kinases, since they possess a short extra cellular domain, and a modified intracellular catalytic do main, In particular, the subdomains directly involved in ATP binding a nd phosphotransfer reaction display remarkable variations, These resul ts suggest that linotte is part of a novel signal transduction cascade involved in learning and memory.