To elucidate the endocrine regulation of vitellogenin (Vg) synthesis in the red flour beetle, Tribolium castaneum, the titers of juvenile hormone (JH) and ecdysteroids in the whole body of female beetles were measured and compared with Vg mRNA levels. Juvenile hormone levels remained high while the ecdysteroid levels declined steadily during 1-5 days post adult emergence (PAE). The Vg mRNA levels began to increase by the end of 3rd day PAE and peaked by the 4th-5th day PAE. Gene expression profiling by microarray and quantitative real-time PCR analyses of RNA isolated from 1 to 5 days PAE beetles revealed that the genes coding for proteins involved in JH biosynthesis and action, but not those involved in 20-hydroxyecdysone (20E) biosynthesis and action had similar expression patterns as the genes coding for Vg. RNA interference (RNAi)-aided knock-down in the expression of these genes showed that both JH and 20E were required for Vg gene expression. However, Vg mRNA was induced by the application of JH III but not by the injection of 20E into the previtellogenic females. These data suggest that JH is required for Vg synthesis in the fat body and 20E influences Vg synthesis through its action on oocyte maturation.
|Number of pages||10|
|Journal||Insect Biochemistry and Molecular Biology|
|State||Published - May 2010|
Bibliographical noteFunding Information:
We thank Dr. Nigel Cooper and Ms. Xiahong Li of University of Louisville for help with microarray analysis. We also thank Dr. Chen and Dr. Rankin of Integrative Biology Department of University of Texas at Austin, Austin, TX, for the help with the estimation of JH titer. This work was supported by National Institutes of Health ( GM070559-06 ). The University of Louisville microarray facility is supported by NCRR IDeA Awards INBRE-P20 RR016481 and COBRE-P20RR018733 . This is contribution number 10-08-057 from the Kentucky Agricultural Experimental Station.
- Gene expression
- Juvenile hormone
ASJC Scopus subject areas
- Molecular Biology
- Insect Science