Biology subjects

Rozen-Gagnon, K.

Publications and source records attributed to Rozen-Gagnon, K..

2 recordsLinked to original sources

bioRxiv2020

A selectable, plasmid-based system to generate CRISPR/Cas9 gene edited and knock-in mosquito cell lines

Aedes (Ae.) aegypti and Ae. albopictus mosquitoes transmit arthropod-borne diseases around the globe, causing ~700,000 deaths each year. Genetic mutants are valuable tools to interrogate both fundamental vector biology and mosquito host factors important for viral infection. However, very few genetic mutants have been described in mosquitoes in comparison to model organisms. The relative ease of applying CRISPR/Cas9 based gene editing has transformed genome engineering and has rapidly increased the number of available gene mutants in mosquitoes. Yet, in vivo studies may not be practical for screening large sets of mutants or possible for laboratories that lack insectaries. Thus, it would be useful to adapt CRISPR/Cas9 systems to common mosquito cell lines. In this study, we generated and characterized a mosquito optimized, plasmid based CRISPR/Cas9 system for use in U4.4 (Ae. albopictus) and Aag2 (Ae. aegypti) cell lines. We demonstrated highly efficient editing of the AGO1 locus and isolated knock-down AGO1 cell lines. Further, we used homology-directed repair to establish knock-in Aag2 cell lines with a 3xFLAG-tag at the N-terminus of endogenous AGO1. These experimentally verified plasmids are versatile, cost-effective, and efficiently edit immune competent mosquito cell lines that are widely used in arbovirus studies.

molecular biology↗

bioRxiv2020

TMEM41B is a pan-flavivirus host factor

Flaviviruses pose a constant threat to human health. These RNA viruses are transmitted by the bite of infected mosquitoes and ticks and regularly cause outbreaks. To identify host factors required for flavivirus infection we performed full-genome loss of function CRISPR-Cas9 screens. Based on these results we focused our efforts on characterizing the roles that TMEM41B and VMP1 play in the virus replication cycle. Our mechanistic studies on TMEM41B revealed that all members of the Flaviviridae family that we tested require TMEM41B. We tested 12 additional virus families and found that SARS-CoV-2 of the Coronaviridae also required TMEM41B for infection. Remarkably, single nucleotide polymorphisms (SNPs) present at nearly twenty percent in East Asian populations reduce flavivirus infection. Based on our mechanistic studies we hypothesize that TMEM41B is recruited to flavivirus RNA replication complexes to facilitate membrane curvature, which creates a protected environment for viral genome replication. HIGHLIGHTSTMEM41B and VMP1 are required for both autophagy and flavivirus infection, however, autophagy is not required for flavivirus infection. TMEM41B associates with viral proteins and likely facilitates membrane remodeling to establish viral RNA replication complexes. TMEM41B single nucleotide polymorphisms (SNPs) present at nearly twenty percent in East Asian populations reduce flavivirus infection. TMEM41B-deficient cells display an exaggerated innate immune response upon high multiplicity flavivirus infection.

molecular biology↗