Thioredoxins are small thiol proteins that have a
conserved active site sequence, WCGPC, and reduce
disulfide bonds in various proteins using the two active site
cysteines, a reaction that oxidizes thioredoxin and renders it
inactive. Thioredoxin reductase returns thioredoxin to its
reduced, active form in a reaction that converts NADPH to
NADP+. The biological functions of thioredoxins vary
widely; they have roles in oxidative stress protection, act as
electron donors for ribonucleotide reductase, and form
structural components of enzymes. To date, three thioredoxin
genes have been characterized in Drosophila melanogaster:
the generally expressed Thioredoxin-2 (Trx-2) and the two
sex-specific genes ThioredoxinT (TrxT) and deadhead
(dhd). The male-specific TrxT and the female-specific dhd
are located as a gene pair, transcribed in opposite directions,
with only 470 bp between their transcription start points. We
show in this study that all three D. melanogaster thioredoxins
are conserved in 11 other Drosophilid species, which are
believed to have diverged up to 40 Ma ago and that Trx-2 is
conserved all the way to Tribolium castaneum. We have
found that the intriguing gene organization and regulation of
TrxT and dhd is remarkably well conserved and identified
potential conserved regulatory sequences. In addition, we
show that the 50–70 C terminal amino acids of TrxT constitute
a hyper-variable domain, which could play a role in
sexual conflict and male–female co-evolution.
2007. Vol. 217, no 9, p. 639-50
Analysis of Variance, Animals, Animals; Genetically Modified, Blotting; Western, Crosses; Genetic, Drosophila/*genetics, Female, Gene Deletion, Genes; Insect, Homozygote, Longevity/*genetics, Male, Membrane Proteins/*genetics/*physiology, Oxidative Stress/*genetics, Thioredoxin/*genetics