Cloning and expression of sprint, a Drosophila homologue of RIN1

The small GTPase Ras is critical for regulation of growth and differentiation during development. The mammalian protein RIN1 is a potential Ras effector protein, which can also interact with the Abelson tyrosine kinase. However, its biological function is unknown. We have identified the Drosophila homologue of RIN1, called sprint, for SH2, poly-proline containing Ras interactor. The sprint locus is very large and contains at least two differentially expressed isoforms (sprint-a and sprint-b). Both isoforms are expressed in the ovary and maternal mRNA is deposited into embryos. In addition, sprint is zygotically expressed in the developing midgut, amnioserosa and in a specific subset of CNS neurons. The expression patterns of the two sprint isoforms are temporally distinct suggesting that the isoforms may have unique functions.