摘 要 ：利用RACE技术从抗逆模式植物盐芥中克隆获得了1个DREB（dehydration responsive element binding）类转录因子基因,命名为ThDREB2B(NCBI登录号EF653377)。结果表明：（1）ThDREB2B基因cDNA全长1 486 bp,包含1个954 bp的开放阅读框,编码316个氨基酸;推测编码的蛋白质分子量约36.0 kD,等电点为4.81,第76~135位氨基酸构成1个AP2结构域。（2）系统进化分析表明,ThDREB2B属于DREB亚家族的A-2亚组,与拟南芥AtDREB2B基因遗传距离最近。（3）半定量RT-PCR检测显示,ThDREB2B基因在正常生长条件下低丰度表达,在低温、干旱或高盐胁迫下上调表达。（4）酵母单杂交结果表明,ThDREB2B蛋白能与DRE元件特异结合,但转录激活能力弱。推测ThDREB2B蛋白可能需要翻译后修饰以获得转录激活功能。
Abstract:A DREB-like gene,designated as ThDREB2B (NCBI Accession No.EF653377) was isolated from Thellungiella halophila,a model plant for stress tolerance research.The result showed that:(1)The cDNA of ThDREB2B was 1 486 bp in full length,contained an open reading frame (ORF) of 954 bp that encoded 316 amino acid residues.The deduced protein was predicted to be 36.0 kD in molecular mass and pI 4.81.The region between residues 76 and 135 was a typical AP2/EREBP DNA-binding domain.(2)The phylogenetic analysis showed that ThDREB2B belonged to the A-2 group of DREB transcription factor subfamily.(3)The expression level of ThDREB2B was relative low in normal growth conditions,and was up-regulated under low temperature,salty,or drought stress.(4)The yeast one-hybrid analysis showed that ThDREB2B could bind to DRE element very specifically,but the transcriptional activate activity was very low.A post-translation modification might be necessary for ThDREB2B to activate the transcription of target genes.