家蝇抗菌肽基因MAF-1的表达模式及响应微生物刺激分析

Expression Pattern of Housefly MAF-1 in Different Development Stages and Its Response to Microbial Stimulation

Musca domestica antifungal peptide-1(MAF-1)是家蝇体(Musca domestica)内组成型表达的一种独特且具有良好抑菌效果的抗真菌肽。本研究利用实时荧光定量PCR技术分析MAF-1在家蝇不同发育时期、不同组织器官及家蝇3龄幼虫经微生物(大肠杆菌、金黄色葡萄球菌和白色念珠菌)刺激后的表达特征。结果显示,MAF-1在家蝇各个发育时期的相对表达量依次为:2龄幼虫>1龄幼虫>3龄幼虫>雄蝇成虫>卵>雌蝇成虫>蛹;MAF-1在家蝇3龄幼虫各组织器官的相对表达量依次为:脂肪体>唾液腺>气管>肠道>体壁。通过超微量显微注射法向家蝇3龄幼虫体内注入病原微生物,其中金黄色葡萄球菌刺激后MAF-1的表达量呈下降趋势;大肠杆菌刺激后MAF-1的表达量先降低后升高再降低;白色念珠菌刺激后MAF-1的表达量先升高然后逐渐下降。本研究从RNA水平上说明了MAF-1的表达随着家蝇幼虫的生长发育阶段变化,对不同微生物刺激的响应具有不同的特征。同时MAF-1还是家蝇抵抗病原微生物感染的重要天然免疫分子,这为进一步研究其参与家蝇天然免疫防御过程提供了基础。

Musca domestica antifungal peptide-1(MAF-1)is a unique antifungal peptide,which is constitutively expressed in Musca domestica with great antifungal effect.In this study,RT-qPCR was used to analyze the expression characteristic of MAF-1 in different developmental stages,different tissues and organs,and the third instar larvaes of Musca domestica under the stimulation of microorganisms(Escherichia coli,Staphylococcus aureus,and Candida albicans).These results showed the expression of MAF-1 at various stages of the Musca domestica:2nd instar larva>1st instar larva>3rd instar larva>male>egg>female>pupa;the expression level ofMAF-1 in tissues and organs was:fat body>salivary gland>trachea>intestinal tract>body wall.The microinjection method was used to induce the expression of MAF-1 by inject pathogenic microorganisms into the 3rd instar larvaes of Musca domestica.Among them,the expression of MAF-1 was down-regulated after stimulated by Staphylococcus aureus;the expression of MAF-1 was down-regulated after stimulated by Escherichia coli,then up-regulated and down-regulated finally;the expression of MAF-1 was up-regulated and then down-regulated after Candida albicans stimulation.This study demonstrates that MAF-1 expression were various in related with different development stages and different microbe stimulation of Musca domestica larvae.Meanwhile,MAF-1 is an important innate immune molecule that helps Musca domestica to resist pathogenic microorganisms infection,which provides a basis for further research on the role of MAF-1 participated in innate immune defense of housefly.