The nucleotide sequence and the tissue-specific expression of Drosophila c-src.

We have examined the coding capability and expression of the Drosophila homolog of the vertebrate proto-oncogene c-src. Sequence analysis of a cDNA clone representing the Drosophila c-src locus suggests that the gene encodes a 62 kd protein that is remarkably similar to the protein product of chicken c-src. The Drosophila c-src locus is transcribed into three mRNAs that are each regulated independently during development. Drosophila c-src RNA is abundant in embryos and pupae but rare in larvae and adults. In situ hybridization reveals that after the first 8 hr of development, c-src RNA accumulates almost exclusively in neural tissues such as the brain, ventral nerve chord, and eye-antennal discs, and in differentiating smooth muscle. We conclude that c-src may not be a mitotic signal but instead may play a role in the development of neural tissue and smooth muscle.