关键词: bHLH, 启动子, 瞬时表达

Abstract: Basichelix-loop-helix (bHLH) transcription factors are widely present in plants, which play important roles in flower morphogenesis, light signal transduction and hormonal signal transduction. However, the molecular mechanisms regulating their expression remain largely unknown. In this paper, we previously cloned a bHLH transcription factor gene from maize, designated ABP7, and preliminary data suggestted that it might be involved in multiple signal transduction pathways such as kernel development and hormone response. For further elucidation of the upstream pathways regulating ABP7 expression, we cloned the 5′ flanking sequence of ABP7, verified its promoter activity by transient expression in maize protoplasts, and predicted its cis-acting elements. The results showed that the cloned 2 266 bp 5 ′ flanking region is a functional promoter which is capable to drive the expression of downstream reporter, and contains many potential cis-acting elements involved in the signaling of hormones such as GA、 IAA and ABA, and responses to adverse environments. These results set a base for future studies in identification of upstream regulatory networks that control ABP7 expression, and in unraveling the specific roles of ABP7 in plant growth, development and stress response.

Key words: bHLH, promoter, transient expression