Site-specific genomic targeting as a functional tool to study diapause in Aedes albopictus

Genome engineering of vector mosquitoes is a powerful tool to address a wide range of fundamental and applied goals.  For example, the ability to modify gene expression in a tissue and development-specific manner is critical for understanding mosquito biology.  Recombinase-mediated-cassette-exchange (RMCE) permits such precise genetic manipulation by integrating transgene constructs at defined genomic regions (“landing-sites”).  Since the transgene can be driven by a tissue or development-specific promoter, the RMCE system allows conditional manipulation of gene expression via site-specific genome modification.  Based on the RMCE strategy, we are developing a transgenic system to study gene function in Aedes albopictus, a widespread and invasive vector capable of transmitting a variety of viruses.  As an abundant human-biting mosquito in urban and suburban environments, Ae. albopictus is of significant public health concern. 
To develop the RMCE system in Ae. albopictus, we used transposon mediated gene insertion to generate fluorescent “landing-site” lines containing two lox-recombination sequences.  In future transformations we will target the lox-sites for RMCE, with the long-term goal of studying the functional genetics of diapause.  Diapause is a crucial overwintering strategy that has enabled Ae. albopictus to spread across all continents except Antarctica.  Based on previous transcriptomics work, we have identified candidate diapause regulatory genes that we will target for knockdown using the RMCE approach.  The multiple landing-site lines also include one male-specific line (the landing-site is ~1.3Mb from the male-determining nix locus), and will provide a valuable resource for studying vector biology and functional genomics in the species.