基于茶树品种‘迎霜’( Camellia sinensis ‘Yingshuang’)的转录组数据,采用PCR方法从其基因组DNA中克隆获得编码DREB转录因子的CsDREB-A1基因。结果显示：该基因的开放阅读框( ORF)长度为585 bp,编码194个氨基酸,该氨基酸序列即为CsDREB-A1转录因子。 CsDREB-A1转录因子的N端含有AP2/ERF家族转录因子典型的AP2 DNA保守结合结构域,其中包含保守的YRG元件和WLG基序,且其第14位和第19位分别为缬氨酸和谷氨酸,该结构域的上、下游分别有PKK/RPAGRxKFxETRHP和DSAW特征序列。通过进化分析可知CsDREB-A1转录因子属于 AP2/ERF 家族中 DREB 亚族的 A1组,其与茶树 CBF 转录因子的相似性较高,与拟南芥[ Arabidopsis thaliana ( Linn.) Heynh.]等植物的DREB类转录因子也有较高的相似性。 CsDREB-A1转录因子为亲水性蛋白,理论相对分子质量为21165.4,理论等电点为pI 9.56,碱性、酸性、芳香族和脂肪族氨基酸比例分别为18%、10%、6%和18%；该转录因子只有1个包含53个氨基酸的无序化区域,且大部分无序化氨基酸位于AP2 DNA保守结合结构域内,无序化氨基酸的比例为27.32%；在CsDREB-A1转录因子的三级结构中,N端有1个ɑ螺旋、C端有3个β折叠。研究结果显示：CsDREB-A1转录因子可能与茶树的抗寒性相关。%On the basis of transcriptome data of Camellia sinensis ‘Yingshuang ’ , CsDREB-A1 gene encoding DREB transcription factor was cloned from its genomic DNA by PCR method. The results show that length of open reading frame ( ORF) of this gene is 585 bp, which encodes 194 amino acids, this amino acid sequence is CsDREB-A1 transcription factor. The N-terminal of CsDREB-A1 transcription factor contains the typical conserved AP2 DNA-binding domain of AP2/ERF family transcription factors, in which contains conserved YRG element and WLG motif, and there are valine and glutamic acid at its 14th and 19th sites, respectively. And there are PKK/RPAGRxKFxETRHP and DSAW characteristic sequences in upstream and downstream of the binding domain, respectively. According to phylogenetic analysis, it is known that CsDREB-A1 transcription factor belongs to A1 group of DREB subfamily in AP2/ERF family. And CsDREB-A1 transcription factor has high similarity to CBF transcription factor from C. sinensis, and also has high similarity to DREB transcription factor from Arabidopsis thaliana ( Linn.) Heynh., etc. CsDREB-A1 transcription factor is hydrophilic protein, its theoretical relative molecular weight is 21 165. 4, theoretical isoelectric point is pI 9. 56, percentage of basic, acidic, aromatic and aliphatic amino acids is 18%, 10%, 6% and 18%, respectively. This transcription factor only has one disordered region containing 53 amino acids, and most of disordered amino acids are located in conserved AP2 DNA-binding domain and percentage of disordered amino acids is 27 . 32%. In tertiary structure of CsDREB-A1 transcription factor, its N-terminal contains one ɑ-helix and its C-terminal contains three β-strands. It is suggested that CsDREB-A1 transcription factor is probably related to cold resistance of C. sinensis.
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