Wei Chen1, Shao-Lei Geng2, Zhe Song2, Yu-Juan Li1, Hui Wang1,3, Jian-Yun Cao4. 1. Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China. 2. State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China. 3. School of Biological Medicine, Beijing City University, Beijing, China. 4. School of Economics and Trade, South China University of Technology, Guangzhou, China.
Abstract
BACKGROUND: Diapause is the arrest of the development of insects and can be used for the development of effective agricultural pest management strategies. Heat shock protein 70 (Hsp70) is reported to be up-regulated during diapause to maintain survival in some insect species. However, its regulatory mechanism is unknown. RESULTS: Expression of hsp70 in Helicoverpa armigera was found to be up-regulated in diapause pupal brains. To elucidate the molecular regulatory mechanisms of hsp70, we focused our attention on its transcription factor, heat shock factor 1 (HSF1). Four alternative splicing variants of HSF1 from pupal brains of H. armigera were identified, and subcellular localization analysis indicated that these variants were exclusively expressed in the nucleus. Real-time PCR analysis showed that all of these variants were up-regulated in diapause pupal brains, and their expression patterns were consistent with that of hsp70. Finally, promoter activity assay and Western blotting detection demonstrated that hsp70 was activated and up-regulated by these variants. CONCLUSION: Expression of hsp70 in H. armigera during diapause is regulated by multiple alternatively spliced isoforms of HSF1. The results of this study may provide important information for understanding the regulatory mechanisms of hsps during insect diapause.
BACKGROUND: Diapause is the arrest of the development of insects and can be used for the development of effective agricultural pest management strategies. Heat shock protein 70 (Hsp70) is reported to be up-regulated during diapause to maintain survival in some insect species. However, its regulatory mechanism is unknown. RESULTS: Expression of hsp70 in Helicoverpa armigera was found to be up-regulated in diapause pupal brains. To elucidate the molecular regulatory mechanisms of hsp70, we focused our attention on its transcription factor, heat shock factor 1 (HSF1). Four alternative splicing variants of HSF1 from pupal brains of H. armigera were identified, and subcellular localization analysis indicated that these variants were exclusively expressed in the nucleus. Real-time PCR analysis showed that all of these variants were up-regulated in diapause pupal brains, and their expression patterns were consistent with that of hsp70. Finally, promoter activity assay and Western blotting detection demonstrated that hsp70 was activated and up-regulated by these variants. CONCLUSION: Expression of hsp70 in H. armigera during diapause is regulated by multiple alternatively spliced isoforms of HSF1. The results of this study may provide important information for understanding the regulatory mechanisms of hsps during insect diapause.