The Drosophila melanogaster homologue of the human BBC1 gene is highly expressed during embryogenesis.

We have previously reported the isolation and preliminary characterisation of a full-length cDNA sequence derived from the human BBC1 gene, a gene which displays differential expression in tumours of the female breast [Adams et al., Hum. Mol. Genet. 1 (1992) 91-96]. Here, we report the isolation and characterisation of the Drosophila melanogaster (Dm) homologue of this human gene. The Dmbbc1 cDNA is 62% identical to the human BBC1 cDNA within a conserved open reading frame and the encoded proteins share 74% sequence similarity. The Dmbbc1 mRNA is expressed at all stages of Dm development, with the highest levels of expression occurring during embryogenesis. In addition, the Dm and human BBC1 proteins share remarkable degrees of identity with the products of recently isolated plant and avian bbc1 cDNAs. The sequences of all the predicted BBC1 proteins are highly similar to that of the rat ribosomal subunit protein L13 [Olvera and Wool, Biochem. Biophys. Res. Commun. 201 (1994) 102-107], strongly indicating that the BBC1 protein is ribosomal protein L13.