Sequence, structure and evolution of the gene coding for sn-glycerol-3-phosphate dehydrogenase inDrosophila melanogaster

Abstract

We present the complete nucleotide and deduced amino acid sequence for the gene encoding Drosophila sn-glycerol-3-phosphate dehydrogenase. A transcription unit of 5kb was identified which is composed of eight protein encoding exons. Three classes of transcripts were shown to differ only in the 3'-end and to code for three protein isoforms each with a different C-terminal amino acid sequence. Each transcript is shown to arise through the differential expression of three isotype-specific exons at the 3'-end of the gene by a developmentally regulated process of 3'-end formation and alternate splicing pathways of the pre-mRNA. In contrast, the 5'-end of the gene is simple in structure and each mRNA is transcribed from the same promoter sequence. A comparison of the organization of the Drosophila and murine genes and the primary amino acid sequence between a total of four species indicates that the GPDH gene-enzyme system is highly conserved and is evolving slowly.

Neutralism and selectionism: the molecular clock

“…In Drosophila melanogaster, the Gpdh gene consists of eight exons and produces three isozymes by differential splicing of the last three exons (Cook et al, 1988;Bewley et al, 1989;von Kalm et al, 1989). We have analyzed in my laboratory 768 nucleotides from exons 3±6, coding for 256 amino acids, in 27 dipteran species (Kwiatowski et al, 1997;Barrio and Ayala, 1997).…”

Reevaluation of Phylogeny in the Drosophila obscura Species Group Based on Combined Analysis of Nucleotide Sequences

“…e Gpdh sequences are from the following studies: all ingroup species ϭ Barrio and Ayala (1997); MEL ϭ Bewley et al (1989). f Adh sequences are from the following studies: AMB ϭ Marfany and Gonzalez-Duarte (1991a); GUA and MAD ϭ Marfany and Gonzalez-Duarte (1993); SOB ϭ Marfany and Gonzalez-Duarte (1991b); TOL ϭ this study; MIR, PBO, and PER ϭ Schaeffer and Miller (1991); PSE ϭ Schaeffer and Miller (1992); MEL ϭ Kreitman (1983); YAK ϭ Ashburner (unpublished).…”

Expression of the GPDH-4 isozyme of sn-glycerol-3-phosphate dehydrogenase in three Drosophila species

“…The D. melanogaster Gpdh gene has eight exons, a single promoter and multiple polyadenylation signals (Bewley et al, 1989;von Kalm et al, 1989). There are two alternate 3 exons -exon 7 and exon 8.…”

“…The transcript containing exons 1 through to 6 codes for GPDH-3 and the transcript containing exons 1-6, skipping exon 7 and including exon 8 encodes GPDH-1 (Bewley et al, 1989;von Kalm et al, 1989). The product of translation of the transcript containing exons 1-7 has not been identified, but it has been suggested that this transcript might be coding for a novel isozyme GPDH-4 .…”

“…The amino acid sequence of GPDH has been obtained from a variety of organisms, and shown to be highly conserved over evolutionary time (Bewley et al, 1989). In fruit fly species this conservation extends to the nucleotide sequence (Kwiatowski et al, 1997) and isozyme patterns (Colgan, 1992).…”