Background The dust mites, which are mostly represented by Dermatophagoides spp. （Acari： Pyroglyphidae）, are the major sources of indoor allergens. Identification and characterization of these mite allergen molecul...Background The dust mites, which are mostly represented by Dermatophagoides spp. （Acari： Pyroglyphidae）, are the major sources of indoor allergens. Identification and characterization of these mite allergen molecules are an important step in the development of new effective diagnostic procedures and possible therapeutic strategies for allergic disorders associated with dust mites. Methods Total RNA was extracted from Dermatophagoides farinae. The gene coding for Der f 3 was amplified by RT-PCR with the primers designed based on previous sequence published in GenBank. The target gene was cloned intermediately into pMD19-T plasmid and finally into plasmid pET28a （＋）, expressed in E. coil BL21 at the aid of the inducer isopropyI-D-thiogalactopyranoside （IPTG）. The physicochemical properties, spatial structure of the allergen were analyzed with bioinformatics software. Results The cDNA coding for group 3 allergen of Dermatophagoides farinae from China was cloned and expressed successfully. Sequencing analysis showed that there were nineteen mismatched nucleotides in five Der f3 cDNA clones in comparison with the reference （GenBank Accession No. AY283291）, which resulted in deduced amino acid sequence incompatibility in eleven residues. Bioinformatics analysis revealed that the Der f 3 pro-protein was an extracellular hydrophobic protein, consisting of 259 amino acids with a 16 amino acid signal peptide. The protein was deduced to have three chymotrypsin active sites （53-68 AA, 108-122 AA and 205-217 AA）, one N-glycosylation site, one cAMP- and cGMP-dependent protein kinase phosphorylation site, four protein kinase C phosphorylation sites, two casein kinase II phosphorylation sites, and five N-myristoylation sites. Conclusions Der f3 is an extracellular hydrophobic protein which possesses multiple activation and phosphorylation sites. Polymorphism may exist in the Der f3 gene but this needs to be further confirmed in the future.展开更多
粉尘螨是诱导过敏性疾病的重要变应原,可诱发Ⅰ型变态反应,对其免疫原性的鉴定是研究过敏性鼻炎等过敏性疾病的基础.首次对粉尘螨过敏原基因Der f 35进行克隆表达、纯化及免疫原性鉴定,提取粉尘螨总核糖核酸(ribonucleic acid,RNA),根...粉尘螨是诱导过敏性疾病的重要变应原,可诱发Ⅰ型变态反应,对其免疫原性的鉴定是研究过敏性鼻炎等过敏性疾病的基础.首次对粉尘螨过敏原基因Der f 35进行克隆表达、纯化及免疫原性鉴定,提取粉尘螨总核糖核酸(ribonucleic acid,RNA),根据已知基因序列(GenBank:LC175222.1)设计引物进行反转录聚合酶链式反应扩增,经Bam H I和Xho I双酶切,连接构建pET-32a-Der f 35载体,并克隆至大肠杆菌TOP 10菌株,取1 mL克隆菌液进行测序.使用试剂盒提取高纯度质粒转至感受态细胞Rosetta(DE3)中进行诱导、表达纯化及免疫学鉴定,并进行同源性比对分析、进化树构建及二级结构预测.克隆和表达结果显示,Der f 35基因的片段长约436个碱基对(base pair,bp);重组蛋白Der f 35相对分子质量约为30 ku(1 u=1 D),与预期结果相符.蛋白质印迹法结果证明,Der f 35与尘螨过敏性疾病患者的血清结合有明显的反应原性.生物信息学进化树结果显示,粉尘螨与屋尘螨、热带无爪螨、害嗜鳞螨、绵羊痒螨和免耳痒螨亲缘关系较近,二级结构预测显示Der f 35的氨基酸序列由2个α螺旋、6个β折叠、2个β转角和10个无规则卷曲片段组成.研究结果可为尘螨过敏性疾病的诊断与治疗提供理论依据.展开更多
基金This work was supported by grants from National Science Foundation of China （No. 30060166 and 30671939）.
文摘Background The dust mites, which are mostly represented by Dermatophagoides spp. （Acari： Pyroglyphidae）, are the major sources of indoor allergens. Identification and characterization of these mite allergen molecules are an important step in the development of new effective diagnostic procedures and possible therapeutic strategies for allergic disorders associated with dust mites. Methods Total RNA was extracted from Dermatophagoides farinae. The gene coding for Der f 3 was amplified by RT-PCR with the primers designed based on previous sequence published in GenBank. The target gene was cloned intermediately into pMD19-T plasmid and finally into plasmid pET28a （＋）, expressed in E. coil BL21 at the aid of the inducer isopropyI-D-thiogalactopyranoside （IPTG）. The physicochemical properties, spatial structure of the allergen were analyzed with bioinformatics software. Results The cDNA coding for group 3 allergen of Dermatophagoides farinae from China was cloned and expressed successfully. Sequencing analysis showed that there were nineteen mismatched nucleotides in five Der f3 cDNA clones in comparison with the reference （GenBank Accession No. AY283291）, which resulted in deduced amino acid sequence incompatibility in eleven residues. Bioinformatics analysis revealed that the Der f 3 pro-protein was an extracellular hydrophobic protein, consisting of 259 amino acids with a 16 amino acid signal peptide. The protein was deduced to have three chymotrypsin active sites （53-68 AA, 108-122 AA and 205-217 AA）, one N-glycosylation site, one cAMP- and cGMP-dependent protein kinase phosphorylation site, four protein kinase C phosphorylation sites, two casein kinase II phosphorylation sites, and five N-myristoylation sites. Conclusions Der f3 is an extracellular hydrophobic protein which possesses multiple activation and phosphorylation sites. Polymorphism may exist in the Der f3 gene but this needs to be further confirmed in the future.
文摘粉尘螨是诱导过敏性疾病的重要变应原,可诱发Ⅰ型变态反应,对其免疫原性的鉴定是研究过敏性鼻炎等过敏性疾病的基础.首次对粉尘螨过敏原基因Der f 35进行克隆表达、纯化及免疫原性鉴定,提取粉尘螨总核糖核酸(ribonucleic acid,RNA),根据已知基因序列(GenBank:LC175222.1)设计引物进行反转录聚合酶链式反应扩增,经Bam H I和Xho I双酶切,连接构建pET-32a-Der f 35载体,并克隆至大肠杆菌TOP 10菌株,取1 mL克隆菌液进行测序.使用试剂盒提取高纯度质粒转至感受态细胞Rosetta(DE3)中进行诱导、表达纯化及免疫学鉴定,并进行同源性比对分析、进化树构建及二级结构预测.克隆和表达结果显示,Der f 35基因的片段长约436个碱基对(base pair,bp);重组蛋白Der f 35相对分子质量约为30 ku(1 u=1 D),与预期结果相符.蛋白质印迹法结果证明,Der f 35与尘螨过敏性疾病患者的血清结合有明显的反应原性.生物信息学进化树结果显示,粉尘螨与屋尘螨、热带无爪螨、害嗜鳞螨、绵羊痒螨和免耳痒螨亲缘关系较近,二级结构预测显示Der f 35的氨基酸序列由2个α螺旋、6个β折叠、2个β转角和10个无规则卷曲片段组成.研究结果可为尘螨过敏性疾病的诊断与治疗提供理论依据.
