Steroid Receptor Co-Activator Is Required for Juvenile Hormone Signal Transduction Through a Bhlh-Pas Transcription Factor, Methoprene Tolerant

JBC Papers in Press. Published on December 28, 2010

STEROID RECEPTOR CO-ACTIVATOR IS REQUIRED FOR JUVENILE HORMONE SIGNAL TRANSDUCTION THROUGH A bHLH-PAS TRANSCRIPTION FACTOR, METHOPRENE TOLERANT Zhaolin Zhang, Jingjing Xu, Zhentao Sheng, Yipeng Sui and Subba R. Palli Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY 40546 Running Head: SRC is required for JH action Address correspondence to S.R. Palli, Phone: 859 257 4962, Fax: 859 323 1120, Email: rpalli@uky.edu SUMMARY Metamorphosis in insects is regulated by juvenile hormone (JH) and ecdysteroids. The mechanism of 20-hydroxyecdysone (20E), but not of JH action, is well understood. A bHLH-PAS family member, methoprene tolerant (Met), plays an important role in JH action. Microarray analysis and RNA interference (RNAi) were used to identify 69 genes that require Met for their hydroprene-regulated expression in the red flour beetle, Tribolium castaneum. Quantitative real-time PCR analysis confirmed microarray data for 13 out of the 16 hydroprene-response genes tested. The members of the bHLH PAS family often function as heterodimers to regulate gene expression and Met is a member of this family. To determine whether other members of the bHLH PAS family are required for the expression of JHresponse genes, we employed RNAi to knockdown the expression of all 11 members of bHLH-PAS family and studied the expression of JH-response genes in RNAi insects. These studies showed that besides Met, another member of this family, steroid receptor co-activator (SRC), is required for the expression of 15 JH-response genes tested. Moreover, studies in JH-responsive Aag-2 cells revealed that Aedes aegypti homologues of both Met and SRC are required for the expression of the JH1  

Copyright 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

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