Variation in sex-, stage- and tissue-specific expression of the amylase genes in Drosophila ananassae

Abstract

Expression of the amylase multigene family of Drosophila ananassae was investigated in thirdinstar larvae and adults. A developmental differentiation was found between the Amyl-2 and Amy3-4 gene clusters, the former being preferentially expressed in larvae, the latter in adults. During adult life, we observed a decrease in Amy] -2 expression in males of certain strains. We have raised some arguments for the existence of trans-active regulators, acting as repressors of Amy]-2 in adults. The putative repressors might exhibit a geographical polymorphism, with a fixed active form in Pacific regions and a polymorphic pattern in Africa, thus increasing the diversity observed in adult amylase phenotypes. A clear differentiation between the two gene clusters was also found in tissue-specific activity along the third-instar larval midgut. In the anterior midgut, only Amy]-2 is active, while both gene groups are expressed in the posterior midgut, with an additional subzonation within it.

Origin and evolution of the Amyrel gene in the α-amylase multigene family of Diptera

“…Duplications may lead to tissue specificity, like in Aedes aegypti (Francischetti et al, 2002), or Drosophila ananassae (Da Lage, Klarenberg & Cariou, 1996). Tissue specificity, mainly due to changes in regulatory regions, may be itself associated to enzymological specificity, also not evidenced to date in such insects.…”

Cloning and Expression Analysis of theBombyx mori α-amylaseGene (Amy) from the Indigenous Thai Silkworm Strain, Nanglai

“…The remaining pair at position 164 and 165 has been found only in some species of Lepidoptera but not in other animals. The different number of disulfide bridges may be related to differences in enzyme activity (Da Lage et al 1996). Finally, the seven conserved motifs found in all animal α-amylase proteins were also present in Nanglai BmAMY (Figure 3).…”

“…The number of introns within the Amy genes of insects varies considerably. In the genus Drosophila, five of 146 species contain genes with no introns and the others have only one intron (Da Large et al 1996). The Amy genes of Apis mellifera (Ohashi et al 1999) and Ceratitis capitata (Da Lage et al 2002) contain only two introns and that of Tribolium castaneum (Abukashawa et al unpublished) has three introns.…”

Variation in sex-, stage- and tissue-specific expression of a-amylase in five species of the Drosophila quinaria section

“…Some of the variability and intensity of expression can be ascribed to the differing structural variants of the amylase; in the genus Drosophila more than two dozen electrophoretically distinguishable iso-amylases have been found (Doane, 1969;Daõ Ènou et al, 1987;Da Lage et al, 1989;Offenberger & Klarenberg, 1993). The gene that codes for the structural characteristics of the a-amylase enzyme is located on different chromosomes in different Drosophila species and can occur as a gene duplication (in D. melanogaster and D. subobscura) or in more than two copies of the amy locus (in D. ananassae, see Da Lage et al, 1995). The evolutionary history of the amylase multigene family in Drosophila is complex; in D. pseudoobscura, their current status is the result of deletions on the third chromosome (Popadic et al, 1996).…”