Regulation and characterization of four CBF transcription factors from Brassica napus
Regulation and characterization of four CBF transcription factors from Brassica napus
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DOI：
10.1023/a:1015570308704
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发表时间：
2002-07-01
影响因子：
5.1
通讯作者：
Singh, J
中科院分区：
文献类型：
--
作者：
Gao, MJ;Allard, G;Singh, J
拟南芥CBF/Dreb转录激活因子基因的四个直向同源物是从冬油菜（Brassica napus，cv.喷气式飞机。所有四个BNCBF克隆编码一个推定的DRE/CRT（LTRE）结合蛋白与AP 2 DNA结合结构域，推定的核定位信号和可能的酸性激活结构域。推导的氨基酸序列表明，BNCBF 5、7和16与拟南芥CBF 1非常相似，而BNCBF 17的不同之处在于它在酸性结构域中含有两个额外的16和21个氨基酸的区域。与BNCBF 17和一种或多种其他BNCBF特异性杂交的转录本在芸苔属幼苗冷暴露30分钟内积累在叶子中，并且先于冷诱导型BN 28基因（来自拟南芥的cor6.6或KIN基因的芸苔属直向同源物）的转录本积累。冷诱导的BNCBF 17 mRNA的积累是快速的，但与与BNCBF 5/7/16杂交的转录物相比是短暂的。与BNCBF 5/7/16中的一种或多种杂交的转录物在植物经受长时间暴露于盐胁迫后以低水平积累。BNCBF 17对盐胁迫没有反应。BNCBF转录本的积累在春季和冬季芸苔属是相似的，但在寒冷的转录本的持续性一般较短，在春季比在冬季类型。BNCBF 5和17蛋白在体外结合冷诱导型BN 115（cor 15 a直系同源物）或BN 28启动子的LTRE结构域。然而，观察到BN 115和BN 28之间对LTRE的差异结合偏好。LTRE的核心CCGAC序列的突变表明BNCBF 17具有比BNCBF 5更低的序列结合特异性。此外，实验表明，LTRE能够驱动BNCBF 5和17在酵母中的Lac-Z报告基因的反式激活。我们的结论是，BNCBFs报告这里可以作为反式作用因子的低温反应在芸苔属，控制冷诱导基因的表达，通过ABA的非依赖性途径。
Four orthologues of the Arabidopsis CBF/Dreb transcriptional activator genes were isolated from the winter Brassica napus, cv. Jet neuf. All four BNCBF clones encode a putative DRE/CRT (LTRE)-binding protein with an AP2 DNA-binding domain, a putative nuclear localization signal and a possible acidic activation domain. Deduced amino acid sequences suggested that BNCBFs 5, 7and 16 are very similar to the Arabidopsis CBF1 whereas BNCBF17 is different in that it contains two extra regions of 16 and 21 amino acids in the acidic domain. Transcripts hybridizing specifically to BNCBF17 and to one or more of the other BNCBFs accumulated in leaves within 30 min of cold exposure of the Brassica seedlings and preceded transcript accumulation of the cold-inducible BN28 gene, a Brassica orthologue of the cor6.6 or KIN gene from Arabidopsis. Cold-induced accumulation of BNCBF17 mRNA was rapid but was short-lived compared to transcripts hybridizing to BNCBF5/7/16. Transcripts hybridizing to one or more of BNCBF5/7/16 accumulated at low levels after the plants were subjected to prolonged exposure to salt stress. BNCBF17 was not responsive to salt stress. BNCBF transcript accumulation was similar in both spring and winter Brassica but the persistence of the transcripts in the cold were generally shorter in the spring than in the winter type. BNCBF5 and 17 proteins bind in vitro to the LTRE domains of the cold-inducible BN115 (cor15a orthologue) or BN28 promoters. Differential binding preferences, however, to LTREs between BN115 and BN28 were observed. Mutation of the core CCGAC sequence of the LTRE indicated that BNCBF17 had a lower sequence binding specificity than BNCBF5. Furthermore, experiments indicated that the LTREs were able to drive BNCBF5 and 17 trans-activation of the Lac-Z reporter gene in yeast. We conclude that the BNCBFs reported here could function as trans-acting factors in low-temperature responses in Brassica, controlling the expression of cold-induced genes through an ABA-independent pathway.