Comparative genomics allows the discovery of cis -regulatory elements in mosquitoes

Abstract

The discovery and mapping of cis-regulatory elements is important for understanding regulation of gene transcription in mosquito vectors of human diseases. Genome sequence data are available for 3 species, Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus (Diptera: Culicidae), representing 2 subfamilies (Culicinae and Anophelinae) that are estimated to have diverged 145 to 200 million years ago. Comparative genomics tools were used to screen genomic DNA fragments located in the 5 -end flanking regions of orthologous genes. These analyses resulted in the identification of 137 sequences, designated ''mosquito motifs,'' 7 to 9 nucleotides in length, representing 18 families of putative cis-regulatory elements conserved significantly among the 3 species when compared to the fruit fly, Drosophila melanogaster. Forty-one of the motifs were implicated previously in experiments as sites for binding transcription factors or functioning in the regulation of mosquito gene expression. Further analyses revealed associations between specific motifs and expression profiles, particularly in those genes that show increased or decreased mRNA abundance in females following a blood meal, and those accumulating transcription products exclusively or preferentially in the midgut, fat bodies, or ovaries. These results validate the methodology and support a relationship between the discovered motifs and the conservation of hematophagy in mosquitoes.gene expression ͉ hematophagy ͉ Aedes ͉ Anopheles ͉ Culex

A cis-regulatory sequence driving metabolic insecticide resistance in mosquitoes: Functional characterisation and signatures of selection

“…However, identification of cis-regulatory elements poses a particular challenge. Whilst some progress has been made in our knowledge of these (Lenhard et al, 2012;Wittkopp and Kalay, 2012), and conserved motifs upstream of genes are identifiable in mosquitoes which may represent cis-regulatory elements (Sieglaff et al, 2009), validated statistical methods for identification of motifs in sequence data are lacking for many species (Down et al, 2007;SaminadinPeter et al, 2012). Transposable elements (TEs) are ubiquitous features of mosquito genomes (Boulesteix and Biemont, 2005;Fernandez-Medina et al, 2011;Tu and Coates, 2004) with some 29% of the assembled Culex quinquefasciatus genome composed of TEs (Arensburger et al, 2010).…”

Transcellular and paracellular pathways of transepithelial fluid secretion in Malpighian (renal) tubules of the yellow fever mosquito Aedes aegypti

“…Where no comparable data exist for mosquitoes, we will touch on the important insights provided by functional genetic studies of Drosophila melanogaster Malpighian tubules. However, over 250 million years of evolution have separated mosquitoes from fruit flies (Sieglaff et al, 2009), and fruit flies may not require the ‘extreme’ renal physiology displayed by female mosquitoes. Thus, data from Drosophila and Aedes Malpighian tubules may not always be exchangeable.…”

A comparative genome-wide study of ncRNAs in trypanosomatids

“…Comparative genomics is an approach that has been used to aid in the discovery of genes, regulatory elements and gene structure [25-27]. It has also been shown as a powerful tool for identifying ncRNA [28-32].…”