|Rinehart, Joseph - Joe|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/20/2006
Publication Date: 5/19/2006
Citation: Rinehart, J.P., Lopez-Martinez, G., Hayward, S.A., Sandro, L.H., Lee, R.E., Denlinger, D.L. 2006. Upregulation of stress associated genes in the overwintering stages of the Antarctic midge, Belgica antarctica [abstract]. Fifth International Symposium on Molecular Insect Science. p. 72.
Technical Abstract: We have investigated the molecular basis of stress resistance in the midge Belgica antarctica, the largest known free-living animal to adapt to a terrestrial existence on the Antarctic continent. Prevalent in specific locations throughout the Antarctic peninsula, this insect has a two-year life cycle and can overwinter in any of its four larval instars. During the austral summer, adults emerge and are present for a brief 1-2 week period. Our research team has investigated the expression of heat shock proteins (hsps) with respect to overwintering and has used suppressive subtractive hybridization to identify additional stress associated genes that might be involved. A comparison of larvae and adults has revealed that several hsps (a small hsp, hsp70, and hsp90) are all strongly upregulated in the larvae as compared to the adults. Additionally, the larvae do not exhibit an ability to further upregulate the expression of these genes in response to thermal or desiccative stress, while the adults retain the ability to respond to thermal extremes. Suppressive subtractive hybridization and northern blot hybridization has revealed a similar expression pattern for several other stress associated genes. Superoxide dismutase, metallothionein and a gene with similarity to vaculor ATPase all exhibit upregulation in larvae as compared to controls. We have also identified other transcripts including actin and a zinc finger protein of unknown function which exhibit a similar pattern of expression and may be implicated in stress adaptation. Further studies on the expression of these genes will prove insightful as we elucidate the molecular mechanisms that have allowed this insect to adapt to the harsh conditions of the Antarctic continent.