Involvement of a nuclear-encoded basic helix-loop-helix protein in transcription of the light-responsive promoter of psbD
Involvement of a nuclear-encoded basic helix-loop-helix protein in transcription of the light-responsive promoter of psbD
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DOI：
10.1104/pp.125.2.595
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发表时间：
2001-02-01
期刊：
影响因子：
7.4
通讯作者：
Yoshida, S
中科院分区：
文献类型：
--
作者：
Baba, K;Nakano, T;Yoshida, S
在叶绿体 psbD 光响应启动子 (LRP) 中，细菌 -10/-35 元件上游存在高度保守的序列。多个序列特异性 DNA 结合蛋白预计会作为转录因子与保守序列结合。使用酵母单杂交筛选拟南芥 cDNA 文库，鉴定出 psbD LRP 上游序列的可能 DNA 结合蛋白。该蛋白质被命名为 PTF1，是一种由 355 个氨基酸组成的新型蛋白质（估计分子量为 39.6），在成熟蛋白质的预测 N 末端区域包含基本的螺旋-环-螺旋 DNA 结合基序。 PTF1-GFP融合蛋白瞬时表达分析表明PTF1定位于叶绿体。在单杂交系统中使用修改后的 DNA 序列，ACC 重复序列被证明对于 PTF1 结合至关重要。在插入 T-DNA 的拟南芥 ptf1 突变体中，psbD LRP mRNA 积累率降低。与野生型相比，突变体子叶呈淡绿色，短日照条件下生长受到抑制。这些结果表明 PTF1 是 psbD LRP 的反式作用因子。
In the chloroplast psbD light-responsive promoter (LRP), a highly conserved sequence exists upstream from the bacterial -10/-35 elements. Multiple sequence-specific DNA binding proteins are predicted to bind to the conserved sequence as transcription factors. Using yeast one-hybrid screening of an Arabidopsis cDNA library, a possible DNA binding protein of the psbD LRP upstream sequence was identified. The protein, designated PTF1, is a novel protein of 355 amino acids (estimated molecular weight of 39.6) that contains a basic helix-loop-helix DNA binding motif in the predicted N-terminal region of the mature protein. Transient expression assay of PTF1-GFP fusion protein showed that PTF1 was localized in chloroplasts. Using the modified DNA sequence in the one-hybrid system, the ACC repeat was shown to be essential for PTF1 binding. The rate of psbD LRP mRNA accumulation was reduced in a T-DNA-inserted Arabidopsis ptf1 mutant. Compared with wild-type plants, the mutant had pale green cotyledons and its growth was inhibited under short-day conditions. These results suggest that PTF1 is a trans-acting factor of the psbD LRP.