Comparative genomic organization of the cbl genes.

The genomic organization of cbl genes from a variety of mammalian and non-mammalian species was determined by a combination of cloning and database searches. Humans and mice have three cbl genes (c-cbl,(1) cblb, and cblc) which show remarkable conservation of the intron/exon structure over the region of the genes which encode the highly conserved N-terminal region of the proteins including the RING finger. Searches of genomic, cDNA, and EST databases revealed that one or more cbl genes exist in chordates, insects, and worms. Comparison of the complexity and genomic organization of the cbl gene family and the predicted Cbl proteins from various species suggests that the three mammalian cbl genes arose by two duplications of an ancestral gene. The genomic organization of the cbl genes from various species provides insight into the evolution of the cbl gene family.