title: Gene structure and multiple mRNA species of Drosophila melanogaster aldolase generating three isozymes with different enzymatic properties.
abstract: Genomic clones encoding the Drosophila aldolase gene were isolated and the organization of the gene was determined. The protein-coding region spanning nearly 3.5 kb consists of five coding exons (exon 2, 3, 4 alpha, 4 beta, and 4 gamma). The insect exon 2 corresponds to exons 2 to 7 of vertebrate aldolase genes and thus appears to have been formed by the fusion of these 6 exons into a single exon during evolution. The Drosophila aldolase gene is predicted to generate mRNAs for three isozymes (alpha-, beta-, and gamma-types) from the primary transcripts by alternative usage of the final three exons. The reverse transcriptase-PCR assay revealed the occurrence of mRNAs for the three isozymic forms at different developmental stages, and tissue-specific expression was also found to occur in adult flies. In addition to the usual type mRNA species for the alpha-, beta-, and gamma-isozymes, two novel forms of mRNAs, alpha beta- and beta gamma-type mRNAs, were detected tissue-specifically in adult flies, although their functions are unpredictable. The alpha beta-mRNA is an alpha-type mRNA in which exon 4 beta remains unspliced, while the beta gamma-mRNA is a beta-type mRNA with the exon 4 gamma remaining unspliced. Recombinant enzymes expressed in Escherichia coli were all active and exhibited different enzymatic properties.
authors.affiliation: Department of Biochemistry, Saga Medical School.
authors.forename: T
authors.initials: T
authors.lastname: Kai
authors.forename: Y
authors.initials: Y
authors.lastname: Sugimoto
authors.forename: T
authors.initials: T
authors.lastname: Kusakabe
authors.forename: R
authors.initials: R
authors.lastname: Zhang
authors.forename: K
authors.initials: K
authors.lastname: Koga
authors.forename: K
authors.initials: K
authors.lastname: Hori
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D004247:DNA; D004331:Drosophila melanogaster / Q000201:enzymology*; D005091:Exons; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics* / Q000378:metabolism; D007438:Introns; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics*; D015183:Restriction Mapping
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D004247:DNA; D005634:Fructose-Bisphosphate Aldolase