松材线虫乙酰胆碱酯酶基因Bx-ace-2的克隆和序列分析

Molecular cloning and characterization of a new acetylcholinesterase gene Bx-ace-2 from pine wood nematode Bursaphelenchus xylophilus

利用RT-PCR和RACE技术克隆了一个松材线虫(Bursaphelenchus xylophilus)乙酰胆碱酯酶基因Bx-ace-2,该基因cDNA全长为2010bp,有1878bp的开放阅读框(ORF),推测其编码的蛋白有625个氨基酸;Bx-ace-2基因组克隆长为2192bp,含有7个内含子。氨基酸序列比对和同源性分析显示:松材线虫Bx-ace-2编码的乙酰胆碱酯酶与已报道的秀丽小杆线虫ACE-1、ACE-3和ACE-4型乙酰胆碱酯酶的相似性为28%～31%,而与秀丽小杆线虫ACE-2及甘薯茎线虫、南方根结线虫、大豆胞囊线虫、马铃薯白线虫和胎生网尾线虫的ACE-2型乙酰胆碱酯酶的氨基酸序列相似性为44%～52%。构建的系统进化树也显示:松材线虫乙酰胆碱酯酶与其他线虫的ACE-2型乙酰胆碱酯酶具有相对更近的遗传距离,因此推测该松材线虫乙酰胆碱酯酶也属于ACE-2型。

A new gene,Bx-ace-2,encoding an acetylcholinesterase （AChE）,was cloned from Bursaphelenchus xylophilus by reverse transcription polymerase chain reaction （RT-PCR） and rapid amplification of cDNA ends （RACE）.The full length cDNA is 2 010 bp with an open reading frame （ORF） of 1 878 bp which was deduced encoding a protein with 625 amino acids.The length of genomic clone of the gene Bx-ace-2 is 2 192 bp which contained seven introns.The deduced protein sequence encoded by Bx-ace-2 from B.xylophilus shares 28%-31% similarities with those of ACE-1,ACE-3 and ACE-4 from Caenorhabditis elegans.However,it shares 44%-52% similarities with ACE-2 from C.elegans,Ditylenchus destructor,Meloidogyne incognita,Heterodera glycines,Globodera pallida and Dictyocaulus viviparus.The phylogenetic analysis of AChEs demonstrated that the protein encoded by Bx-ace-2 was clustered into a same group with ACE-2 type of acetylcholinesterases from the aforementioned nematodes.Therefore,it was deduced that the protein encoded by Bx-ace-2 belonged to ACE-2 type of acetylcholinesterase.