Clemmons Alexa W, Lindsay Scott A, Wasserman Steven A
Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America.
PLoS Pathog. 2015 Apr 27;11(4):e1004876. doi: 10.1371/journal.ppat.1004876. eCollection 2015 Apr.
In Drosophila melanogaster, recognition of an invading pathogen activates the Toll or Imd signaling pathway, triggering robust upregulation of innate immune effectors. Although the mechanisms of pathogen recognition and signaling are now well understood, the functions of the immune-induced transcriptome and proteome remain much less well characterized. Through bioinformatic analysis of effector gene sequences, we have defined a family of twelve genes - the Bomanins (Boms) - that are specifically induced by Toll and that encode small, secreted peptides of unknown biochemical activity. Using targeted genome engineering, we have deleted ten of the twelve Bom genes. Remarkably, inactivating these ten genes decreases survival upon microbial infection to the same extent, and with the same specificity, as does eliminating Toll pathway function. Toll signaling, however, appears unaffected. Assaying bacterial load post-infection in wild-type and mutant flies, we provide evidence that the Boms are required for resistance to, rather than tolerance of, infection. In addition, by generating and assaying a deletion of a smaller subset of the Bom genes, we find that there is overlap in Bom activity toward particular pathogens. Together, these studies deepen our understanding of Toll-mediated immunity and provide a new in vivo model for exploration of the innate immune effector repertoire.
在黑腹果蝇中，对入侵病原体的识别会激活Toll或Imd信号通路，从而引发先天免疫效应分子的强烈上调。尽管目前对病原体识别和信号传导的机制已经有了很好的理解，但免疫诱导的转录组和蛋白质组的功能仍不太清楚。通过对效应基因序列的生物信息学分析，我们定义了一个由十二个基因组成的家族——博马宁（Boms）——它们由Toll特异性诱导，编码具有未知生化活性的小分泌肽。利用靶向基因组工程，我们删除了十二个Bom基因中的十个。值得注意的是，使这十个基因失活会使微生物感染后的存活率降低到与消除Toll信号通路功能相同的程度，且具有相同的特异性。然而，Toll信号传导似乎未受影响。通过检测野生型和突变型果蝇感染后的细菌载量，我们提供了证据表明博马宁是抵抗感染而非耐受感染所必需的。此外，通过构建并检测博马宁基因较小亚组的缺失，我们发现博马宁对特定病原体的活性存在重叠。这些研究共同加深了我们对Toll介导的免疫的理解，并为探索先天免疫效应分子库提供了一个新的体内模型。
