Decoys Dif/Dorsal to Reduce Antimicrobial Peptide Products for Restoring Toll Immunity Homeostasis.

Avoiding excessive or insufficient immune responses and maintaining homeostasis are critical for animal survival. Although many positive or negative modulators involved in immune responses have been identified, little has been reported to date concerning whether the long non-coding RNA (lncRNA) can regulate immunity response. In this study, we firstly discover that the overexpression of can inhibit the expressions of antimicrobial peptides () and () in vivo, thereby suppressing the Toll signaling pathway. Secondly, our results demonstrate that can interact with transcription factors Dif/Dorsal in the nucleus based on both subcellular localization and RIP analyses. Thirdly, our findings reveal that can decoy Dif/Dorsal away from the promoters of and to repress their transcriptions by ChIP-qPCR and dual luciferase report experiments. Fourthly, the dynamic expression changes of , , and in wild-type flies () at different time points after stimulation disclose that can help restore immune homeostasis in the later period of immune response. Overall, our study reveals a novel mechanism by which serves as a Dif/Dorsal decoy to downregulate antimicrobial peptide expressions for restoring Toll immunity homeostasis, and provides a new insight into further studying the complex regulatory mechanism of animal innate immunity.