中文摘要：

为了研究Caspases家族在昆虫发育变态中的作用,通过RT-PCR扩增并结合RACE技术,克隆得到家蝇Muscadomestica Caspase-1基因1条,命名为Mdom-Caspase-1（GenBank中cDNA序列号为EU854472,氨基酸序列号为ACF71490）。该基因全长1295bp,阅读框序列870bp,共编码289个氨基酸,理论分子量32.83kDa,等电点8.67。Mdom-Caspase-1蛋白有5个保守的半胱氨酸位点QACQG,具有Caspase的典型特征;整个分子呈现亲水性,有8个区域共89个氨基酸为亲酯性,蛋白质二级结构主要由11个α螺旋区、7个β-折叠区、17个β-转角区组成。昆虫间Caspase-1分子具有明显的保守性,Mdom-Caspase-1与黑腹果蝇Drosophila melanogaster、埃及伊蚊Aedes aegypti和致倦库蚊Culex quinquefasciatus的Caspase-1氨基酸序列相似性为65%～77%。RT-PCR半定量分析结果表明,Mdom-Caspase-1基因在家蝇各个虫态中均有表达,但在卵期、3龄幼虫、预蛹、蛹和羽化5d的雌虫中的表达量明显高于其他虫态。这些结果提示Caspase-1可能与昆虫发育变态关系密切,为进一步研究昆虫Caspase-1功能、设计Caspase-1抑制剂提供了分子基础。

英文摘要：

Members of the Caspase family play a central and evolutionary role in apoptosis, which remove the unwanted, damaged and dangerous cells during development to maintain homeostasis. In this study, by using the total RNA isolated from the whole body of the house fly, Musca domestica, the full-length sequence of Mdom-caspase-1 gene encoding the Caspase-1 was cloned by the methods of reverse transcription polymerase chain reaction （RT-PCR） and rapid amplification eDNA ends （RACE） to explore the function of caspase in insect growth and metamorphism. The sequence analysis showed that Mdomcaspase-1 encodes 289 amino acid residues and the 1 295 bp full-length eDNA contains an 870 bp open reading frame （ORF）. The GenBank accession numbers of cDNA and amino acid of Mdom-caspase-1 are EU854472 and ACF71490, respectively. The deduced Mdom-caspase-1 protein （MW 32.83 kDa; pI 8. 67） has 5 conserved cysteines QACQG, which is one of the typical characteristics of Caspase. The Mdomcaspase-1 protein is hydrophilic, while 8 regions containing 89 amino acids are hydrophobic. The protein secondary structure mainly consists of 11 ot helices, 7 [3 folders and 17 turns. The phylogenetic tree was created from the alignments of the amino acid sequences, and the analysis revealed that Caspase-1 possessed distinct conservation in evolution and the amino acid sequence of Mdom-caspase-1 is 65%-77% identical to Caspase-1 from Drosophila melanogaster, Aedes aegypti and Culex quinquefasciatus. The results of RT-PCR revealed that Mdom-caspase-1 was expressed in every stage of M. domestica, and in five stages including the egg, 3rd instar larva, pre-pupa, pupa and the 5 d adult female the expression levels were obviously higher than those in other stages. The results suggest that the Caspase-1 gene may have some relationships with the growth and metamorphism of insects. These results would provide some valuable information to explore the molecular function of Caspase-1 in insects and develop the specific Caspase-1 inhibitors.