Onfelt Tingvall T, Roos E, Engström Y
Department of Molecular Biology and Functional Genomics, Arrhenius Laboratories for Natural Sciences, Stockholm University, S-106 91 Stockholm, Sweden.
EMBO Rep. 2001 Mar;2(3):239-43. doi: 10.1093/embo-reports/kve048.
Surfaces of higher eukaryotes are normally covered with microorganisms but are usually not infected by them. Innate immunity and the expression of gene-encoded antimicrobial peptides play important roles in the first line of defence in higher animals. The immune response in Drosophila promotes systemic expression of antimicrobial peptides in response to microbial infection. We now demonstrate that the epidermal cells underlying the cuticle of larvae respond to infected wounds by local expression of the genes for the antimicrobial peptide cecropin A. Thus, the Drosophila epidermis plays an active role in the innate defence against microorganisms. The immune deficiency (imd) gene was found to be a crucial component of the signal-induced epidermal expression in both embryos and larvae. In contrast, melanization, which is part of the wound healing process, is not dependent on the imd gene, indicating that the signalling pathways promoting melanization and antimicrobial peptide gene expression can be uncoupled.
高等真核生物的体表通常覆盖着微生物，但通常不会被它们感染。固有免疫和基因编码的抗菌肽的表达在高等动物的第一道防线中发挥着重要作用。果蝇中的免疫反应会促进抗菌肽在微生物感染时的系统性表达。我们现在证明，幼虫表皮下的表皮细胞通过局部表达抗菌肽天蚕素A的基因来应对感染伤口。因此，果蝇表皮在抵御微生物的固有防御中发挥着积极作用。免疫缺陷（imd）基因被发现是胚胎和幼虫中信号诱导的表皮表达的关键组成部分。相比之下，作为伤口愈合过程一部分的黑化并不依赖于imd基因，这表明促进黑化和抗菌肽基因表达的信号通路可能是解偶联的。
