Background bacteria exchange genes by three canonical mechanisms: natural transformation, conjugation and transduction. Archaea undergo tremendous amounts of horizontal gene transfer (HGT), and…

This federal contract award to the University of Connecticut (UConn) in Storrs, CT is for a research grant (Award ID: 80NSSC18K1533) focused on investigating gene transfer mechanisms in the archaeal model organism Haloferax volcanii. The $913,558.53 grant, awarded by the National Aeronautics and Space Administration (NASA), aims to identify and characterize the molecular components responsible for cell-cell contact mediated gene exchange (mating) in this archaeal species, as well as explore quorum sensing systems and the roles of host immune mechanisms on horizontal gene transfer. The research seeks to better understand the high rates of gene exchange observed in haloarchaea, which could have implications for understanding evolutionary processes in extremophiles. This grant does not have a set-aside designation. As a leading public research university, UConn frequently conducts federally funded R&D projects across disciplines to support national priorities.

Background bacteria exchange genes by three canonical mechanisms: natural transformation, conjugation and transduction. Archaea undergo tremendous amounts of horizontal gene transfer (HGT), and haloarchaea specifically are well documented to have i) exchanged genes within species at rates that randomize alleles within populations (like sexually reproducing eukaryotes); II) exchange genes at rates higher than those seen between bacterial model species and genera; III) have acquired thousands of genes from bacterial sources􀁉 e.g., their aerobic respiration comes largely from bacteria. However, the mechanisms for how they do IT, and the extent to which they do IT are largely uncharacterized. Using the model archaeon haloferax volcanii, we have previously shown a cell-contact dependent mechanism (called mating) for gene exchange moves>500KB fragments between species at a rate higher than seen in bacterial model organisms. Recently, we have begun to unravel the mechanisms behind gene transfer in h. Volcanii. Our goals in this proposal are to identify and characterize genes responsible for HGT in the archaeon h. Volcanii; to identify and characterize components of quorum sensing and if IT regulates mating; determine rates of HGT within and between haloarchaeal species; and to assess the roles of host􀁉immune􀁉 systems on gene transfer. The specific objectives of the research are: 1) identify and characterize molecular components necessary for the cell-cell contact mediated gene exchange (mating) in h. Volcanii. 2) identify and characterize components of a homoserine lactone based quorum sensing system in h. Volcanii 3) examine frequencies of h. Volcanii for intra- VS. Inter-species, and inter-genus exchange for both modes of HGT, and investigate the roles of host􀁉immune􀁉 systems (e.g., restriction/modification and crispr-CAS), mismatch repair and recombination machinery, which are all known to affect HGT in bacterial model systems, in their ability to increase or decrease those rates in an archaeon.