Lloyd A M, Schena M, Walbot V, Davis R W
Department of Biochemistry, Stanford University, CA 94305.
Science. 1994 Oct 21;266(5184):436-9. doi: 10.1126/science.7939683.
The Arabidopsis mutant ttg lacks both trichomes (epidermal hairs) and anthocyanin pigments. Trichomes and anthocyanins are restored by the constitutive expression of the maize transcriptional regulator (R). The expression of an R-glucocorticoid receptor chimeric protein results in a steroid hormone-dependent, conditional allele of R that functions in whole Arabidopsis plants. The response of the chimeric protein to pulses of hormone was used to define the pattern and timing of trichome formation on the developing leaf epidermis. Each adaxial epidermal leaf cell appears to have an equal probability of differentiating into a trichome; there is a temporal zone of decision for trichome cell fate that proceeds as a wave from the tip to the base of developing leaves.
拟南芥突变体ttg既没有毛状体（表皮毛）也没有花青素色素。通过玉米转录调节因子（R）的组成型表达可恢复毛状体和花青素。R-糖皮质激素受体嵌合蛋白的表达产生了一种依赖类固醇激素的、有条件的R等位基因，该等位基因在整个拟南芥植株中起作用。利用嵌合蛋白对激素脉冲的反应来确定发育中的叶片表皮上毛状体形成的模式和时间。每个叶片近轴表皮细胞似乎都有同等的概率分化为毛状体；毛状体细胞命运存在一个时间性的决定区域，它作为一个波从发育中叶片的尖端向基部推进。
