Mechanisms of Olfaction in Insects - ResearchSpace@Auckland ...
Mechanisms of Olfaction in Insects - ResearchSpace@Auckland ...
Mechanisms of Olfaction in Insects - ResearchSpace@Auckland ...
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Identification <strong>of</strong> putative odorant receptors from Epiphyas postvittana 124<br />
Of the four potential candidate PRs identified from E. postvittana based on am<strong>in</strong>o<br />
acid identity and sex-biased expression, the full length cDNA was obta<strong>in</strong>ed for only<br />
EpOR34. Seven TM doma<strong>in</strong>s are predicted for EpOR34 by a consensus us<strong>in</strong>g seven<br />
different prediction programs, comparable to the predicted TM doma<strong>in</strong>s obta<strong>in</strong>ed for<br />
EpOR1, 2 and 3; and keep<strong>in</strong>g with the notion <strong>of</strong> seven TM doma<strong>in</strong>s for moth ORs. An<br />
alignment <strong>of</strong> the predicted TM doma<strong>in</strong>s <strong>of</strong> these four E. postvittana ORs show that the<br />
TM regions are conserved across the four ORs. Furthermore the general locations <strong>of</strong><br />
the predicted TMs <strong>of</strong> the E. postvittana ORs align with the predicted TM doma<strong>in</strong><br />
regions <strong>of</strong> the H. virescens ORs (Krieger et al., 2002) and a consensus <strong>of</strong> the B. mori<br />
homologues. This <strong>in</strong>dicates that the relative positions <strong>of</strong> the TM doma<strong>in</strong>s <strong>in</strong> ORs may<br />
be conserved across the Lepidoptera. A short C-term<strong>in</strong>us was predicted by both<br />
SPLIT and HMMTOP, comparable to the short C-term<strong>in</strong>us predicted <strong>in</strong> topologies <strong>of</strong><br />
EpOR1, EpOR2 and EpOR3, perhaps a feature conserved <strong>in</strong> <strong>in</strong>sects (Jordon, 2006).<br />
Some Drosophila ORs have also been shown to have short C-term<strong>in</strong>i (Clyne et al.,<br />
1999; Gao and Chess, 1999; Dobritsa et al., 2003; Kiely, 2008). This could just be an<br />
artefact <strong>of</strong> the prediction algorithms used and only the solved structure <strong>of</strong> such a<br />
prote<strong>in</strong> will be able to confirm this theoretical observation.<br />
F<strong>in</strong>ally, the stage has been set for identification and characterisation <strong>of</strong> the PRs <strong>of</strong> E.<br />
postvittana, with four candidates PRs be<strong>in</strong>g identified. Further work <strong>in</strong>to the tissue<br />
localisation through <strong>in</strong> situ hybridisation experiments and functional characterisation<br />
either us<strong>in</strong>g <strong>in</strong> vivo or <strong>in</strong> vitro characterisation assays will confirm the roles <strong>of</strong> these<br />
receptors <strong>in</strong> E. postvittana olfaction.