Section Symposium
Physiology, Biochemistry, and Toxicology
Sheng Li (he/him/his)
Director/Professor
South China Normal University
Guangzhou, Guangdong, China (People's Republic)
Kang Li
South China Normal University
Guangzhou, Guangdong, China (People's Republic)
Shihui Long
South China Normal University
Guangzhou, Guangdong, China (People's Republic)
The abundance of transcription factors and chromatin accessibility coordinately determine the spatiotemporal expression of genes that control growth and development. It is well documented that juvenile hormone-activated Kr-h1 antagonizes 20-hydroxyecdysone (20E)-induced expression of the pupal specifier Br-C to prevent larval-pupal metamorphosis in holometabolous insects. Here, we first revealed that during the larval-prepupal transition in Drosophila melanogaster, the 20E-activated Kr-h1-Br-C axis is a prerequisite for wing disc morphogenesis. Moreover, we discovered that 20E-EcR/USP-Met-Tai directly activates Kr-h1 that upregulates Br-C expression via a positive Kr-h1 binding site (PKBS) in the Br-C enhancer. Furthermore, we showed that 20E-induced H3K27 acetylation increases chromatin accessibility of the PKBS-containing enhancer region to Kr-h1, facilitating Br-C expression that promotes pupariation. These data showed that in response to different hormone stimuli, a single transcription factor either negatively or positively regulates the expression of the same target gene depending on chromatin accessibility, thus manipulating distinct developmental events.