A comprehensive gene expression atlas of sex- and tissue-specificity in the malaria vector, Anopheles gambiae

Abstract

BackgroundThe mosquito, Anopheles gambiae, is the primary vector of human malaria, a disease responsible for millions of deaths each year. To improve strategies for controlling transmission of the causative parasite, Plasmodium falciparum, we require a thorough understanding of the developmental mechanisms, physiological processes and evolutionary pressures affecting life-history traits in the mosquito. Identifying genes expressed in particular tissues or involved in specific biological processes is an essential part of this process.ResultsIn this study, we present transcription profiles for ~82% of annotated Anopheles genes in dissected adult male and female tissues. The sensitivity afforded by examining dissected tissues found gene activity in an additional 20% of the genome that is undetected when using whole-animal samples. The somatic and reproductive tissues we examined each displayed patterns of sexually dimorphic and tissue-specific expression. By comparing expression profiles with Drosophila melanogaster we also assessed which genes are well conserved within the Diptera versus those that are more recently evolved.ConclusionsOur expression atlas and associated publicly available database, the MozAtlas (http://www.tissue-atlas.org), provides information on the relative strength and specificity of gene expression in several somatic and reproductive tissues, isolated from a single strain grown under uniform conditions. The data will serve as a reference for other mosquito researchers by providing a simple method for identifying where genes are expressed in the adult, however, in addition our resource will also provide insights into the evolutionary diversity associated with gene expression levels among species.

Multicopper oxidase-1 is a ferroxidase essential for iron homeostasis in Drosophila melanogaster

“…Previous studies of gene expression in D. melanogaster found that MCO1 mRNA is most abundant in late stage embryos, feeding stage larvae, and adults, and that MCO1 is expressed predominantly in the digestive system (midgut, hindgut, and crop) and Malpighian tubules (17,18). These expression profiles are similar to those of MCO1 orthologues in Anopheles gambiae and Manduca sexta (19)(20)(21). To establish whether MCO1 functions as a ferroxidase in D. melanogaster, we purified recombinant MCO1 and analyzed its enzymatic activity, performed immunohistochemistry to determine the location of MCO1 within the insect, and evaluated the loss-of-function phenotypes generated by RNAi-mediated knockdown.…”

Role of Testis-Specific Gene Expression in Sex-Chromosome Evolution of Anopheles gambiae

“…A recently published catalog of tissue-specific expression in Anopheles (MozAtlas, http://www.tissue-atlas.org) reveals that ,10% of testis-enriched genes are male-biased in expression because they are largely undetected in wholebody samples (Baker et al 2011). This contrasts with the ovaries in which .50% of genes have female-biased expression, a finding that is likely to account for elevated levels of female transcription observed in whole-body samples (Hahn and Lanzaro 2005).…”

Odorant receptor-mediated sperm activation in disease vector mosquitoes

“…S2). Independently, expression of AgOrs in testes, including AgOrco and three other AgOrs identified in our RNAseq studies (Table 1), was found in a previous microarray study by Baker et al, where AgOr37 was specifically recognized as being enhanced in male testes (30). These multiple lines of evidence support the hypothesis that AgOr transcripts are expressed in testes, and in some cases, their expression is similar in amplitude to antennal-expressed AgOr transcripts where RPKMs were often observed to be less than 10 (5).…”

“…5. Asterisks indicate transcripts that were present in at least one of four testes samples as determined by an independent microarray analysis (30); double asterisks indicate transcripts that displayed enhanced expression in testes relative to at least one other tissue; nd, not determined; probe for these transcripts not included on microarray (30). See Dataset S1 for a more detailed listing of RNAseq results.…”