Project description:We custom-built a bioinformatics pipeline to search for 20E-modifying enzymes in the accessory glands of Anopheles gambiae males, searching for ecdysteroid kinases (EcK), ecdysone oxidases (EO), and ecdysteroid-phosphate phosphatases (EPP). To this end, we generated RNAseq datasets of different An. gambiae tissues dissected from virgin and mated females and males, and produced similar datasets for Anopheles albimanus, a South American species that does not synthetize and transfer ecdysteroids during mating. These analyses led to the identification of one candidate EPP and two potential EcKs (EcK1 and EcK2), which we demonstrated are involved in the activity of a male-specific oxidized ecdysteroid (3D20E). We further determined that 3D20E is specifically produced by the An. gambiae male accessory glands and is transferred to females during copulation, where it triggers a series of post-mating responses.
Project description:In Drosophila, the accessory gland proteins (Acps) secreted from the male accessory glands (MAGs) and transferred along with sperm into the female reproductive tract have been implicated in triggering postmating behavioral changes, including refractoriness to subsequent mating and propensity to egg laying. Recently, Acps have been found also in Anopheles, suggesting similar functions. Understanding the mechanisms underlying transcriptional regulation of Acps and their functional role in modulating Anopheles postmating behavior may lead to the identification of novel vector control strategies to reduce mosquito populations. We identified heat-shock factor (HSF) binding sites within the Acp promoters of male Anopheles gambiae and discovered three distinct Hsf isoforms; one being significantly up-regulated in the MAGs after mating. Through genome-wide transcription analysis of Hsf-silenced males, we observed significant down-regulation in 50% of the Acp genes if compared to control males treated with a construct directed against an unrelated bacterial sequence. Treated males retained normal life span and reproductive behavior compared to control males. However, mated wild-type females showed a ∼46% reduction of egg deposition rate and a ∼23% reduction of hatching rate (∼58% combined reduction of progeny). Our results highlight an unsuspected role of HSF in regulating Acp transcription in A. gambiae and provide evidence that Acp down-regulation in males leads a significant reduction of progeny, thus opening new avenues toward the development of novel vector control strategies.
Project description:Whole genome transcription was quantified in adult female and male Anopheles gambiae atdifferent ages; 0 (0-24 h), 10, 20 and 30 days post-eclosion. The objective of the experiment was to identify genes with significant age-dependent transcription.
Project description:Proteomic analysis of Anopheles gambiae brain tissue after in-gel trypsin digestion. To gain insights into neurobiology of the Anopheles gambiae mosquito, we carried out a proteomic analysis of its brain using a comprehensive proteomic approach.
Project description:Whole genome transcription was quantified in adult female and male Anopheles gambiae atdifferent ages; 0 (0-24 h), 10, 20 and 30 days post-eclosion. The objective of the experiment was to identify genes with significant age-dependent transcription. One-colour gene expression arrays were run in duplicate on both male and female RNA samples at the following ages; 0 (0-24 h), 10, 20 and 30 days post-eclosion.
Project description:We characterize the epigenome of the human malaria vector Anopheles gambiae in midgut cells by mapping the distribution and levels of two post-translational histone modifications, H3K27ac and H3K27me3. These histone profiles were then correlated with levels of gene expression obtained by RNA-seq.
Project description:In Drosophila, the accessory gland proteins (Acps) secreted from the male accessory glands (MAGs) and transferred along with sperm into the female reproductive tract have been implicated in triggering postmating behavioral changes, including refractoriness to subsequent mating and propensity to egg laying. Recently, Acps have been found also in Anopheles, suggesting similar functions. Understanding the mechanisms underlying transcriptional regulation of Acps and their functional role in modulating Anopheles postmating behavior may lead to the identification of novel vector control strategies to reduce mosquito populations. We identified heat-shock factor (HSF) binding sites within the Acp promoters of male Anopheles gambiae and discovered three distinct Hsf isoforms; one being significantly up-regulated in the MAGs after mating. Through genome-wide transcription analysis of Hsf-silenced males, we observed significant down-regulation in 50% of the Acp genes if compared to control males treated with a construct directed against an unrelated bacterial sequence. Treated males retained normal life span and reproductive behavior compared to control males. However, mated wild-type females showed a ?46% reduction of egg deposition rate and a ?23% reduction of hatching rate (?58% combined reduction of progeny). Our results highlight an unsuspected role of HSF in regulating Acp transcription in A. gambiae and provide evidence that Acp down-regulation in males leads a significant reduction of progeny, thus opening new avenues toward the development of novel vector control strategies. Total RNA from 4-d-old dsLacZ-treated controls and HSF-silenced males was extracted using TRIzol reagent (Life Technologies), following protocols set according to manufacturer’s instructions. RNA preparation, labelling, hybridization and data analysis were performed by the Oxford Gene Technology (OGT) company. In particular, RNA was further cleaned up using the RNeasy Mini Kit (Qiagen) followed by ethanol precipitation. Sample passing the purity metrics (260/280 and 260/230 ratio) were considered for labeling and hybridization procedures. Labeling was done with cyanine 3 (dsHSF1 and dsHSF123) and cyanine 5 (control dsLacZ). Samples and controls were hybridized in triplicates to the Agilent Mosquito Gene expression arrays (4x44,000, Agilent Technologies, Santa Clara, CA, USA). Data analysis was performed by OGT according to a standardized procedure, as implemented by the software applications Feature Extraction (version 9.5.3.1.), and Genespring GX (version 11.0). Expression data was first normalised using linear and loess normalization in Feature Extraction, then it was imported into Genespring where it was converted into normalised log ratios. The distribution of the data between and within the treatments was checked via boxplots and hierarchical clustering to confirm consistency. Intensity measures from spots flagged as being of poor quality were excluded. Then, the control probes were removed for the statistical analysis: t-tests were carried out for each condition with null hypothesis of log ratio being equal to zero. This was done on the normalised log ratios from the 3 technical replicates. Probes meeting a cut-off of p<0.05 with Benjamini-Hochberg multiple testing correction and with a fold change cutoff greater than 2 were considered statistically and biologically relevant and were used to generate lists of differentially expressed targets.