Levashina E A, Langley E, Green C, Gubb D, Ashburner M, Hoffmann J A, Reichhart J M
UPR 9022 CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 Rue René Descartes, Strasbourg 67084, France.
Science. 1999 Sep 17;285(5435):1917-9. doi: 10.1126/science.285.5435.1917.
The antifungal defense of Drosophila is controlled by the spaetzle/Toll/cactus gene cassette. Here, a loss-of-function mutation in the gene encoding a blood serine protease inhibitor, Spn43Ac, was shown to lead to constitutive expression of the antifungal peptide drosomycin, and this effect was mediated by the spaetzle and Toll gene products. Spaetzle was cleaved by proteolytic enzymes to its active ligand form shortly after immune challenge, and cleaved Spaetzle was constitutively present in Spn43Ac-deficient flies. Hence, Spn43Ac negatively regulates the Toll signaling pathway, and Toll does not function as a pattern recognition receptor in the Drosophila host defense.
果蝇的抗真菌防御由spätzle/Toll/cactus基因盒控制。在此，编码一种血液丝氨酸蛋白酶抑制剂Spn43Ac的基因发生功能丧失突变，结果显示会导致抗真菌肽果蝇霉素的组成型表达，且这种效应由spätzle和Toll基因产物介导。免疫攻击后不久，spätzle被蛋白水解酶切割成其活性配体形式，且切割后的spätzle在Spn43Ac缺陷型果蝇中持续存在。因此，Spn43Ac负向调节Toll信号通路，且在果蝇宿主防御中Toll并非作为模式识别受体发挥作用。
