Ace2, rather than ace1, is the major acetylcholinesterase in the silkworm, Bombyx mori
Ace2, rather than ace1, is the major acetylcholinesterase in the silkworm, Bombyx mori
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ACE2（而非 ACE1）是家蚕 (Bombyx mori) 中主要的乙酰胆碱酯酶
DOI：
10.1111/j.1744-7917.2009.01259.x
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发表时间：
2009-08-01
期刊：
影响因子：
4
通讯作者：
Han, Zhao-Jun
中科院分区：
文献类型：
--
作者：
Chen, Hui-Juan;Liao, Zhen;Han, Zhao-Jun
已有两个乙酰胆碱酯酶(ACEs)基因在多种昆虫中被报道。在烟青虫和小菜蛾等害虫中，ACE1基因编码优势突触酶，是有机磷和氨基甲酸酯类农药的主要靶标。有报道称，农药的选择对ACE基因的进化有影响。驯化的家蚕也有两个Ace基因。在过去的几十年里，由于家蚕没有面临农药选择，我们研究了家蚕的ACE基因表达和酶活性。用实时定量聚合酶链式反应检测血管紧张素转换酶基因Bm-ACE1和Bm-ACE2的表达水平。BM-ACE2在不同发育阶段或不同组织中的表达均高于BM-ACE1，表明ACE2而不是ACE1是家蚕乙酰胆碱酯酶(AChE)的主要类型。这与前述鳞翅目农业害虫不一致，部分原因是杀虫剂的广泛使用可能诱导这些害虫中ACE1基因的高表达。BM-ACE1基因除在头部高表达外，还在丝腺中高表达，BM-ACE2在胚系中含量丰富，提示这两个基因在发育过程中可能具有潜在的非水解性作用。此外，我们还发现，在1龄和3龄幼虫中，两个ACE基因的mRNA水平及其比值(ACE2/ACE1)逐日变化。这对使用粗提物作为酶溶液来估计酶活性的传统方法提出了挑战，因为它是AChE1和AChE2的混合物。为了进行可靠的毒理学分析，需要一种有效而简单的方法来分离不同的AChE。
Two acetylcholinesterase (ace) genes have been reported in many insect species. In pests such as Helicoverpa assulta and Plutella xylostellas, ace1 gene encodes the predominant synaptic enzyme that is the main target of organophosphorus (OP) and carbamate pesticides. It has been reported that pesticide selection has an impact on the ace gene evolution. The domesticated silkworm, Bombyx mori, also has two ace genes. We studied ace gene expression and enzyme activities in silkworm as this has not faced pesticide selection over the past decades. The expression levels of two ace genes, Bm-ace1 and Bm-ace2, were estimated by quantitative real-time polymerase chain reaction. Bm-ace2 was expressed more highly than Bm-ace1 in all tested samples of different developmental stages or tissues, suggesting ace2, rather than ace1, is the major type of acetylcholinesterase (AChE) in Bombyx mori. This is inconsistent with the aforementioned lepidopterons agricultural pests, partly be due to the widespread use of pesticides that may induce high expression of the ace1 gene in these pests. Besides high expression in the head, Bm-ace1 also expresses highly in the silk glands and Bm-ace2 is abundant in the germline, implying both ace genes may have potential non-hydrolytic roles in development. Furthermore, we found that the mRNA levels of two ace genes and their ratios (ace2/ace1) change day to day in the first and third instars. This challenges the conventional method of estimating enzymatic activity using crude extract as an enzyme solution, as it is a mixture of AChE1 and AChE2. An efficient and simple method for separating different AChEs is necessary for reliable toxicological analyses.