sn-Glycerol-3-phosphate dehydrogenase in the honey bee Apis mellifera -an unusual phenotype associated with the loss of introns

Abstract

In comparison with the numerous Drosophila species and the mouse, the Gpdh gene in the honey bee Apis mellifera lacks most introns. This prevents the gene from producing different GPDH isoforms by alternative splicing, which occurs in Drosophila melanogaster. The sequences of the cDNA and genomic Gpdh of A. mellifera are described and show that at the amino acid level they share 84% similarity and 71% identity with D. melanogaster. The identity at the nucleotide level is 62% in the coding region, but no significant similarities were detected in the UTRs. Northern analyses revealed an accumulation of unspliced Gpdh pre-mRNA in the honey bee, probably reflecting splicing inefficiency, although it is also possible that splicing is a regulated step in Gpdh expression in A. mellifera. It is suggested that the intron loss occurred via reverse transcription of a mature Gpdh transcript.