Genomic organization and putative promoters of highly conserved glutathione S-transferases originating by alternative splicing in Anopheles dirus

The genomic DNA of a GST class I alternative splicing gene has been charact erized from Anopheles dirus, a Thai malaria vector. This gene organization is highly conserved in An. dirus and Anopheles gambiae (aggst1 alpha), with >80% nucleotide identity in the coding region. Their gene organization con tains six exons for four mature GST transcripts, which share exon 1 and exo n 2 but vary between four different exon 3 sequences (exon 3A-3D). The dedu ced amino acid sequence of the GST transcripts from these two genes also sh ows very high conservation, with 85-93% identity for each orthologous gene. Two putative promoters and possible regulatory elements were predicted by a combination of the TSSW and MatInspector programs. The Ad214 promoter is proposed to be involved in developmental stage regulation. The Ad2112 promo ter would appear to respond to intra- or extracellular stimuli. These two A nopheline species appear to have diverged in the distant past based on gene neighbors and phylogenetic data, yet these GST genes are still conserved. Therefore it is highly probable that this GST gene organization has one or more important roles. (C) 2001 Elsevier Science Ltd. All rights reserved.