Isolation and characterization of abl gene sequences in Calliphora erythrocephala

Screening of genomic DNA libraries with hybridization probes derived from a Drosophila melanogaster c-abl proto-oncogene homologue resulted in the isolation of a set of related sequences from the dipteran Calliphora erythrocephala. Although the region encompassing the c-abl protein kinase domain encodes a polypeptide extremely similar to the Drosophila gene, considerable inter- and intraspecific divergence is found adjacent to this region. Restriction-site heterogeneity and cross-hybridization studies between individual cloned isolates suggest that abl homologues represent a small gene family in the Calliphora genome. As is the case in Drosophila, abl-related transcripts appear to be low in abundance, are synthesized during oogenesis and stored as a maternal mRNA.