RESUMO
In this study, we used extensive expressed sequence tag evidence obtained through 454 and Solexa next-generation sequencing to explore mtDNA transcription in male and female first instar larvae of Aedes aegypti and adults of Aedes aegypti, Anopheles gambiae, and Anopheles quadrimaculatus. Relative abundances of individual transcripts differed considerably within each sample, consistent with the differential stability of messenger RNA species. Large differences were also observed between species and between larval and adult stages; however, the male and female larval samples were remarkably similar. Quantitative PCR analysis of selected genes, cox1, l-rRNA and nd5, in larvae and adults of Ae. aegypti and in An. gambiae adults was consistent with the RNA-Seq-based quantification of expression. Finally, the absence of a conserved mtDNA region involved in transcriptional control in other dipterans suggests that mosquitoes have evolved a distinct mechanism of regulation of gene expression in the mitochondrion.
Assuntos
Aedes/genética , Anopheles/genética , Perfilação da Expressão Gênica/métodos , Genes Mitocondriais , Proteínas de Insetos/genética , Aedes/metabolismo , Envelhecimento , Animais , Anopheles/metabolismo , Sequência de Bases , Complexo IV da Cadeia de Transporte de Elétrons/genética , Etiquetas de Sequências Expressas , Feminino , Regulação da Expressão Gênica , Genes de RNAr , Proteínas de Insetos/metabolismo , Larva/genética , Larva/metabolismo , Masculino , Dados de Sequência Molecular , NADH Desidrogenase/genética , Reação em Cadeia da Polimerase , RNA Mensageiro/genética , Caracteres SexuaisRESUMO
In spite of the many recent developments in the field of vector sialomics, the salivary glands of larval mosquitoes have been largely unexplored. We used whole-transcriptome microarray analysis to create a gene-expression profile of the salivary gland tissue of fourth-instar Anopheles gambiae larvae, and compare it to the gene-expression profile of a matching group of whole larvae. We identified a total of 221 probes with expression values that were (a) significantly enriched in the salivary glands, and (b) sufficiently annotated as to allow the prediction of the presence/absence of signal peptides in their corresponding gene products. Based on available annotation of the protein sequences associated with these probes, we propose that the main roles of larval salivary secretions include: (a) immune response, (b) mouthpart lubrication, (c) nutrient metabolism, and (d) xenobiotic detoxification. Other highlights of the study include the cloning of a transcript encoding a previously unknown salivary defensin (AgDef5), the confirmation of mucus secretion by the larval salivary glands, and the first report of salivary lipocalins in the Culicidae.
Assuntos
Anopheles/genética , Perfilação da Expressão Gênica , Sequência de Aminoácidos , Animais , Anopheles/classificação , Anopheles/crescimento & desenvolvimento , Anopheles/metabolismo , Sequência de Bases , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/química , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Filogenia , Glândulas Salivares/química , Glândulas Salivares/metabolismo , Alinhamento de SequênciaRESUMO
The alimentary canal of the larval mosquito displays a considerable degree of physiological compartmentalization among its different anatomical sub-divisions (gastric caeca, anterior midgut, posterior midgut and hindgut). We performed a comparative microarray analysis in order to identify transcripts which are particularly enriched in each gut section. Based on the available annotation of the selected transcripts, we suggest that the metabolism and absorption of proteins and carbohydrates takes place mainly in the gastric caeca and posterior midgut, whereas the anterior midgut specializes in the metabolism and absorption of lipids. Transcripts encoding antimicrobial peptides were found to be enriched in the gastric caeca, and a high enrichment of transcripts associated with enzymes involved in xenobiotic detoxification was found in the anterior midgut. Furthermore, our data support the notion that the region encompassing the hindgut and Malpighian tubes plays important roles in avoiding the excretion of nutrients, as well as in xenobiotic detoxification.
