Ecology & Evolution Seminar Series 2015 - Ingrid Richter

Date: 2 April 2015 Time: 12.00 pm

Ingrid Richter presents Molecular evolution and functional characterisation of tunicate xenobiotic receptors.

ingrid Vertebrate pregnane X receptor (PXR, NR1I2), a ligand-activated nuclear receptor, regulates expression of detoxification genes. Vertebrate PXR orthologues may adaptively evolve to bind deleterious/toxic xenobiotics typically encountered by organisms from their diet. Tunicates (phylum Chordata) are marine filter-feeders that form a sister clade to the Vertebrata. Genomes of two tunicate taxa, Ciona intestinalis and Botryllus schlosseri, encode at least two PXR orthologues. The research outcomes presented in this talk demonstrate that tunicate xenobiotic receptors may provide a source of sensor elements that have been pre-moulded by natural selection for detecting bioactive chemicals. Using next-generation sequencing, high intra-taxa genetic diversity was observed within three tunicate xenobiotic receptor orthologues. These data supported the notion that tunicate xenobiotic receptors might enhance binding of dietary exogenous bioactive compounds (e.g. toxins) typically encountered by these organisms. This provided the foundation for the development of a generic bioassay for assessing the activity of these biological compounds. Recombinant yeast strains were developed in which ligand-dependent activation of tunicate xenobiotic receptors was transduced into easily quantifiable phenotypic changes in the yeast strains. These tunicate yeast bioassays have the potential for detecting microalgal biotoxins, bioactive compounds that may provide templates for drug development and environmental contaminants.

For more information, please contact Dr Heiko Wittmer at heiko.wittmer@vuw.ac.nz