Coordinate responses of transcription factors to ecdysone during programmed cell death in the anterior silk gland of the silkworm, Bombyx mori

• Published in: Insect molecular biology 2006-06, Vol.15 (3), p.281-292
• Main Authors: Sekimoto, T, Iwami, M, Sakurai, S
• Format: Article
• Language: English
• Subjects: 20-hydroxyecdysone; Animals; anterior silk gland; apoptosis; Bombyx - physiology; Bombyx mori; Cell Death - physiology; Drosophila; Drosophila - physiology; early and early late genes; early genes; early-late genes; ecdysone receptors; ecdysterone; Ecdysterone - physiology; exocrine glands; Gene Expression; Gene Expression Regulation, Developmental; Genes, Insect; hormonal regulation; hormone receptors; messenger RNA; metamorphosis; Metamorphosis, Biological - physiology; programmed cell death; Salivary Glands - physiology; transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 0962-1075; 1365-2583
• DOI: 10.1111/j.1365-2583.2006.00641.x

Programmed cell death (PCD) in Bombyx mori anterior silk glands (ASGs) is triggered by 20-hydroxyecdysone (20E). We examined the expression profiles and effects of 20E on 11 transcription factor genes in the fifth instar to determine whether they demonstrate the hierarchical control seen in Drosophila PCD. Results indicate that EcR-A and usp-2, but not EcR-B1 or usp-1, may be components of the ecdysone receptor complex. Up-regulation of E75A, BHR3, and three BR-C isoforms, but not E75B, appeared to be associated with the induction of PCD. βFTZ-F1 was not expressed during PCD execution. Thus, gene control in B. mori ASGs differs from that in Drosophila salivary glands, despite both tissues undergoing PCD in response to 20E at pupal metamorphosis.