Interactions Among Steroid and Xenobiotic Response Cascades in the Regulation of CYP6B1

In support of this idea, treatment with the synthetic aryl hydrocarbon benzo[alpha]pyrene or the plant signaling molecule salicylic acid in combination with xanthotoxin resulted in in vitro transcription that was similar to treatment with either chemical alone, suggesting that the response cascades to aryl hydrocarbons, signaling molecules, and furanocoumarins are distinct. In contrast, treatment with the insect steroid molting hormone 20-hydroxyecdysone in combination with xanthotoxin interfered with induction by xanthotoxin. However, CYP6B1 appears to be regulated at many levels. Treatment with the antioxidant caffeic acid in combination with xanthotoxin enhanced in vitro transcription of CYP6B1v3. Dietary exposure of black swallowtail caterpillars to either allelochemical alone induced P450-mediated xanthotoxin metabolism in vivo; however, simulataneous exposure to both chemicals repressed in vivo P450-mediated metabolism, possibly due to competition for binding the CYP6B1 catalytic site or for overlapping promoter elements. If this is the case, the upstream ARE could be evolving into an element mediating the xanthotoxin response. These findings are the first report of the conservation of aryl hydrocarbon-inducible regulation between insects and mammals and suggest that the evolution of the regulation of detoxificative genes might have occurred in various stages with novel response cascades developing from existing ones.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Entomology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Brown, Rebecca Alice Petersen

Contributors dc:contributor

• Berenbaum, May R.
• Schuler, Mary A.

• Biology, Molecular

Language dc:language

eng

Identifier

(MiAaPQ)AAI3086022

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/86440