Promoter of a cotton fibre MYB gene functional in trichomes of Arabidopsis and glandular trichomes of tobacco

【原创】

本文介绍的是一在烟草腺毛、拟南芥表皮毛中特异性表达的启动子。

本文采用的实验手段：启动子克隆、载体构建、侵染拟南芥、转化烟草，得到转基因的拟南芥和转基因烟草，通过GUS染色和GUS蛋白相对活性测定，由此确定了GaMYB2 promoter has a high activity in cotton fibre；GaMYB2 promoter displays trichome-specific activity in Arabidopsis；GaMYB2 promoter confers specificity to glandular trichomes in tobacco；通过PLACE分析，PLACE analysis revealed a T/G-box element (AACGTG)
present at -226 to -221, which attracted attention. 通过Promoter deletion analysis，发现 a modified promoter, P-AB1, that lacked the T/G-box was generated by removing a 20 bp fragment (-233 to
-214) from P-440. Arabidopsis plants harbouring P-AB1::GUS exhibited a strong reduction of the GUS signalin the trichome  and the specific activity of GUS in leaf proteins was dramatically decreased。Another promoter, P-AB2, was then made in which a 87 bp fragment (-317 to -231) was removed from P-440, while the T/G box was intact. Analysis of Arabidopsis plants revealed that deletion of this 87 bp sequence resulted in only a marginal loss of activity，这两点证据也支持了T/G-box present in this region may serve as a cis-acting element conferring promoter activity in trichomes. 最后作者以60 bp DNA fragment containing

43 T/G-box 为标签，通过酵母单杂交证实GL3（一拟南芥表皮毛表达的基因）能与T/G-box结合。Recognition of the T/G-box motif by GL3 and GhDEL65 prompted the question whether both transcription factors would activate the GaMYB2 promoter in planta.

此文章采用了一系列基本生物学实验，较为全面的讲述了研究一启动子的基本方法，值得阅读。