A recessive mutation, immune deficiency (imd), defines two distinct control pathways in the Drosophila host defense.

In this paper we report a recessive mutation, immune deficiency (imd), that impairs the inducibility of all genes encoding antibacterial peptides during the immune response of Drosophila. When challenged with bacteria, flies carrying this mutation show a lower survival rate than wild-type flies. We also report that, in contrast to the antibacterial peptides, the antifungal peptide drosomycin remains inducible in a homozygous imd mutant background. These results point to the existence of two different pathways leading to the expression of two types of target genes, encoding either the antibacterial peptides or the antifungal peptide drosomycin. IMAGES:

本研究报道了一种隐性突变——免疫缺陷（immune deficiency，imd），该突变会抑制果蝇（Drosophila）免疫应答过程中所有抗菌肽编码基因的诱导激活。当受到细菌侵染时，携带该突变的果蝇存活率显著低于野生型果蝇。我们同时发现，与抗菌肽不同，在纯合imd突变体背景下，抗真菌肽drosomycin仍可被正常诱导表达。上述结果提示，存在两条不同的信号通路，分别调控两类靶基因的表达：一类编码抗菌肽，另一类编码抗真菌肽drosomycin。图片：