Schulze-Lefert P, Becker-André M, Schulz W, Hahlbrock K, Dangl J L
Department of Biochemistry, Max-Planck-Institut für Züchtungsforschung, Köln, Federal Republic of Germany.
Plant Cell. 1989 Jul;1(7):707-14. doi: 10.1105/tpc.1.7.707.
We have combined in vivo genomic footprinting and light-induced transient expression of chalcone synthase promoter derivatives in parsley protoplasts to identify cis sequences regulating light activation. The parsley chalcone synthase promoter contains two cis "units" that are light-responsive. Each unit is composed of short DNA stretches of approximately 50 base pairs, and each contains two in vivo footprints. One of the footprints in each unit covers a sequence that is highly conserved among other light- and stress-regulated plant genes. The other footprinted sequences in each unit are not related to each other. The TATA distal light-responsive unit is inherently weak but can compensate partially for the loss of the stronger TATA proximal unit. Levels of light-induced expression from either can be influenced by the presence of a region of approximately 100 base pairs located upstream of the TATA distal light-responsive unit. Combination of the light-responsive units and upstream region generates a synergistic response to light. We speculate that functional compensation generated by nonidentical, but sequence-related, cis units foreshadows combinatorial diversity of cognate trans factors.
我们将体内基因组足迹分析与查尔酮合酶启动子衍生物在欧芹原生质体中的光诱导瞬时表达相结合,以鉴定调控光激活的顺式作用序列。欧芹查尔酮合酶启动子包含两个对光有响应的顺式“单元”。每个单元由大约50个碱基对的短DNA片段组成,且每个单元都有两个体内足迹。每个单元中的一个足迹覆盖了在其他光和胁迫调控的植物基因中高度保守的序列。每个单元中其他有足迹的序列彼此不相关。TATA远端光响应单元本身较弱,但可以部分补偿较强的TATA近端单元的缺失。任一单元的光诱导表达水平都可能受到位于TATA远端光响应单元上游约100个碱基对区域的影响。光响应单元与上游区域的组合对光产生协同反应。我们推测,由不相同但序列相关的顺式单元产生的功能补偿预示着同源反式作用因子的组合多样性。