BR-C Z4 and FoxJ interact to regulate expression of a chitin synthase gene CHSA-2b in the pupal wing discs of the silkworm, Bombyx mori

Jie Zhang; Guanfeng Xu; Binbin Qiu; Xiaojuan Zhang; Qili Feng; Qing Yang; Sichun Zheng

doi:10.1016/j.ibmb.2019.103264

BR-C Z4 and FoxJ interact to regulate expression of a chitin synthase gene CHSA-2b in the pupal wing discs of the silkworm, Bombyx mori

Insect Biochem Mol Biol. 2020 Jan:116:103264. doi: 10.1016/j.ibmb.2019.103264. Epub 2019 Nov 7.

Authors

Jie Zhang¹, Guanfeng Xu¹, Binbin Qiu¹, Xiaojuan Zhang¹, Qili Feng¹, Qing Yang², Sichun Zheng³

Affiliations

¹ Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China; Guangzhou Key Laboratory of Insect Development Regulation and Applied Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China.
² Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian, 116024, China.
³ Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China; Guangzhou Key Laboratory of Insect Development Regulation and Applied Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China. Electronic address: sczheng@scnu.edu.cn.

PMID: 31707207
DOI: 10.1016/j.ibmb.2019.103264

Abstract

Elaborate regulation of tissue- and stage-specific expression of genes is prerequisite for insect development. The hormone 20-hydroxyecdysone (20E) initiates metamorphosis by regulating the expression of a series of genes. However, how 20E orderly regulates the pupa-specific expression of genes remains unclear. In this study, we report a regulatory mechanism for the pupa-specific expression of chitin synthase A 2b (CHSA-2b) in Bombyx mori. We found that Broad-Complex Z4 (BR-C Z4) was up-regulated by 20E just before pupation, while transcription factor FoxJ and CHSA-2b were up-regulated during the pupal stage. There is a Fox cis-regulatory element in the CHSA-2b promoter region, and FoxJ protein bound to this element, enhancing the CHSA-2b transcription during the pupal stage. In addition to CHSA-2b, FoxJ also up-regulated the expression of 16 out of 19 pupa-specific genes tested. However, at the prepupal stage, 20E-induced BR-C Z4 inhibited the FoxJ transcription, indirectly inhibiting the CHSA-2b transcription. These data suggest that at the pre-pupation stage, 20E-induced BR-C Z4 inhibited the expression of pupa-stage genes like CHSA-2b by inhibiting the expression of FoxJ; by the pupal stage, the expression of BR-C Z4 decreased, releasing its inhibition on FoxJ, which then up-regulated the expression of the pupa-specific genes. This study explains the elaborate regulation of the pupa-specific gene expression during metamorphosis in B. mori.

Keywords: BR-C Z4; Bombyx mori; CHSA-2b; FoxJ; Pupa-specific gene; Transcription regulation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Bombyx / genetics*
Bombyx / growth & development*
Chitin Synthase / genetics*
Chitin Synthase / metabolism
Ecdysterone / metabolism
Forkhead Transcription Factors / genetics*
Forkhead Transcription Factors / metabolism
Gene Expression Regulation, Developmental*
Insect Proteins / genetics*
Insect Proteins / metabolism
Metamorphosis, Biological
Pupa / genetics
Pupa / growth & development
Up-Regulation
Wings, Animal / growth & development

Substances

Forkhead Transcription Factors
Insect Proteins
Ecdysterone
Chitin Synthase