Multi-tissue GAL4-mediated gene expression in all Anopheles gambiae life stages using an endogenous polyubiquitin promoter

Abstract

The ability to manipulate the Anopheles gambiae genome and alter gene expression effectively and reproducibly is a prerequisite for functional genetic analysis and for the development of novel control strategies in this important disease vector. However, in vivo transgenic analysis in mosquitoes is limited by the lack of promoters active ubiquitously. To address this, we used the GAL4/UAS system to investigate the promoter of the An. gambiae Polyubiquitin-c (PUBc) gene and demonstrated its ability to drive expression in mosquito cell culture before incorporation into An. gambiae transgenic driver lines. To generate such lines, piggyBac-mediated insertion was used to identify genomic regions able to sustain widespread expression and to create φC31 docking lines at these permissive sites. Patterns of expression induced by PUBc-GAL4 drivers carrying single intergenic insertions were assessed by crossing with a novel responder UAS-mCD8:mCherry line that was created by φC31-mediated integration. Amongst the drivers created at single, unique chromosomal integration loci, two were isolated that induced differential expression levels in a similar multiple-tissue spatial pattern throughout the mosquito life cycle. This work expands the tools available for An. gambiae functional analysis by providing a novel promoter for investigating phenotypes resulting from widespread multi-tissue expression, as well as identifying and tagging genomic sites that sustain broad transcriptional activity.