The CCAAT binding factor can mediate interactions between CONSTANS-like proteins and DNA
The CCAAT binding factor can mediate interactions between CONSTANS-like proteins and DNA
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DOI：
10.1111/j.1365-313x.2006.02706.x
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发表时间：
2006-05-01
期刊：
影响因子：
7.2
通讯作者：
Lifschitz, E
中科院分区：
文献类型：
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作者：
Ben-Naim, O;Eshed, R;Lifschitz, E
Constans-like(Col)蛋白是植物特有的核基因表达调控因子，但不包含已知的DNA结合基序。我们测试了一种常见的DNA结合蛋白是否可以将这些蛋白输送到特定的顺式作用元件。我们筛选了与Col蛋白亚群中的两个成员相互作用的蛋白质。这些COL蛋白分别是番茄COL1(TCOL1)和拟南芥ATCO(ATCO)蛋白，TCOL1似乎不参与开花时间的控制，ATCO蛋白介导光周期诱导开花。我们发现这两种蛋白的C末端植物特异性CCT(CO，CO-like，CAB表达时间1)结构域通过其HAP5/NF-YC成分与三聚体CCAAT结合因子(CBF)结合。染色质免疫沉淀表明TCOL被HAP5征集到酵母Cyc1和HEM1启动子的CCAAT基序中。在拟南芥中，CBF的三个组成部分中的每一个都由几个高度转录的不同基因编码。在温暖的长日照条件下，番茄HAP5(THAP5a)基因的高水平表达可以缩短拟南芥的开花时间。TCOL1 CCT结构域的突变破坏了THAP5与THAP5的相互作用，ATCO的类似突变破坏了THAP5的功能，推迟了开花。因此，CBF很可能在植物中将Col蛋白招募到其DNA靶标模体中。
CONSTANS-Like (COL) proteins are plant-specific nuclear regulators of gene expression but do not contain a known DNA-binding motif. We tested whether a common DNA-binding protein can deliver these proteins to specific cis-acting elements. We screened for proteins that interact with two members of a subgroup of COL proteins. These COL proteins were Tomato COL1 (TCOL1), which does not seem to be involved in the control of flowering time, and the Arabidopsis thaliana CONSTANS (AtCO) protein which mediates photoperiodic induction of flowering. We show that the C-terminal plant-specific CCT (CO, CO- like, TIMING OF CAB EXPRESSION 1) domain of both proteins binds the trimeric CCAAT binding factor (CBF) via its HAP5/NF-YC component. Chromatin immunoprecipitation demonstrated that TCOL is recruited to the CCAAT motifs of the yeast CYC1 and HEM1 promoters by HAP5. In Arabidopsis, each of the three CBF components is encoded by several different genes that are highly transcribed. Under warm long days, high levels of expression of a tomato HAP5 (THAP5a) gene can reduce the flowering time of Arabidopsis. A mutation in the CCT domain of TCOL1 disrupts the interaction with THAP5 and the analogous mutation in AtCO impairs its function and delays flowering. CBFs are therefore likely to recruit COL proteins to their DNA target motifs in planta.