Yanagisawa S, Izui K
Department of Chemistry, Faculty of Science, Kyoto University, Japan.
Mol Gen Genet. 1990 Dec;224(3):325-32. doi: 10.1007/BF00262425.
The expression of the phosphoenolpyruvate carboxylase (PEPC) gene involved in C4 photosynthesis is regulated in a highly organized manner. Nuclear factors interacting with DNA fragments from the 5' flanking region (from positions -1012 to +88 relative to the transcription start site) of the maize gene were identified by gel shift assays. Among the three kinds of such nuclear proteins (MNF1, MNF2a and MNF2b) found in the extract from maize leaves, MNF2a and MNF2b, which were distinguishable by their chromatographic behavior, interacted with the same motif of the repeated sequence (RS2) in the region from -432 to -201. MNF1 interacted with the region from -905 to -818 in which two copies of another kind of repeated sequence (RS1) reside. All of these nuclear factors were found only in the extracts from green and etiolated leaves but not in those from stems and roots. The relative content of MNF1 and MNF2b was almost equal in green and etiolated leaves, while that of MNF2a was significantly higher in etiolated leaves than green leaves. It is suggested that expression of the PEPC gene is controlled by the combined effects of these nuclear factors.
参与C4光合作用的磷酸烯醇式丙酮酸羧化酶（PEPC）基因的表达受到高度有序的调控。通过凝胶迁移实验鉴定了与玉米基因5'侧翼区域（相对于转录起始位点从-1012到+88）的DNA片段相互作用的核因子。在玉米叶片提取物中发现的三种此类核蛋白（MNF1、MNF2a和MNF2b）中，MNF2a和MNF2b可通过色谱行为区分，它们与-432至-201区域中重复序列（RS2）的相同基序相互作用。MNF1与-905至-818区域相互作用，该区域存在另一种重复序列（RS1）的两个拷贝。所有这些核因子仅在绿色和黄化叶片的提取物中发现，而在茎和根的提取物中未发现。绿色和黄化叶片中MNF1和MNF2b的相对含量几乎相等，而MNF2a在黄化叶片中的含量明显高于绿色叶片。提示PEPC基因的表达受这些核因子的综合作用控制。
