Two distinct pathways can control expression of the gene encoding the Drosophila antimicrobial peptide metchnikowin
Two distinct pathways can control expression of the gene encoding the Drosophila antimicrobial peptide metchnikowin
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DOI：
10.1006/jmbi.1998.1705
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发表时间：
1998-05-08
影响因子：
5.6
通讯作者：
Imler, JL
中科院分区：
文献类型：
--
作者：
Levashina, EA;Ohresser, S;Imler, JL
Metchnikowin是最近从果蝇中发现的一种富含脯氨酸的多肽，具有抗菌和抗真菌特性。像大多数来自昆虫的其他抗菌肽一样，它的表达是免疫诱导的。在这里，我们提出的证据表明，诱导Metchnikowin基因的表达可以通过Toll途径或通过IMD基因产物来介导。我们发现，该基因在Toll缺陷突变株和IMD突变株中仍然是可诱导的，在Toll缺陷突变株中，抗真菌反应被阻断，在IMD突变株中，未能启动抗菌反应。然而，在Toll缺陷；IMD双突变体中，免疫攻击后不能再检测到metchnikowin基因的表达。我们的结果表明，这种具有双重活性的多肽的表达可以由细菌或真菌感染产生的信号触发。对该基因的克隆表明，在昆虫免疫基因启动子的5‘侧翼区域存在几个可能的顺式调控基序：Rel位点、GATA基序、干扰素共识反应元件和NF-IL6反应元件。将GFP报告基因置于1.5 kb的metchnikowin基因上游序列控制下的转基因果蝇品系的建立表明，该片段能够赋予转基因植物充分的免疫诱导性和表达的组织特异性。(C)1998年学术出版社有限公司。
Metchnikowin is; a recently discovered proline-rich peptide from Drosophila with antibacterial and antifungal properties. Like most other antimicrobial peptides from insects, its expression is immune-inducible. Here we present evidence that induction of metchnikowin gene expression can be mediated either by the TOLL pathway or by the imd gene product. We show that the gene remains inducible in Toll-deficient mutants, in which the antifungal response is blocked, as well as in imd mutants, which fail to mount an antibacterial response. However, in Toll-deficient;imd double mutants, metchnikowin gene expression can no longer be detected after immune challenge. Our results suggest that expression of this peptide with dual activity can be triggered by signals generated by either bacterial or fungal infection. Cloning of the metchnikowin gene revealed the presence in the 5' flanking region of several putative cis-regulatory motifs characterized in the promoters of insect immune genes: namely, Rel sites, GATA motifs, interferon consensus response elements and NF-IL6 response elements. Establishment of transgenic fly lines in which the GFP reporter gene was placed under the control of 1.5 kb of metchnikowin gene upstream sequences indicates that this fragment is able to confer full immune inducibility and tissue specificity of expression on the transgene. (C) 1998 Academic Press Limited.