Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2021 Jan 18;14:57. doi: 10.1186/s13071-020-04562-9

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© The Author(s) 2021

Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

PMC Copyright notice

Fig. 1 — Summary of RNA interference (RNAi) pathways identified in Dermanyssus gallinae. RNAi pathways are based on those described in Tetranychus urticae and Drosophila melanogaster with core RNAi pathway enzymes either present (red) or absent (grey) in D. gallinae. siRNA pathway: double-stranded RNA (dsRNA; either viral or experimentally introduced) is processed by Dicer-2 (Dcr-2) into 21- to 23-nucleotide small interfering RNAs (siRNAs) and loaded into the RNA-induced silencing complex (RISC) complex. Argonaute (Ago) cleaves the passenger strand of the siRNA and retains the guide strand which guides the active siRISC complex to the target mRNA. Full complementarity between the guide siRNA strand and target mRNA leads to cleavage of the mRNA. miRNA pathway: The microRNA (miRNA) gene is transcribed in the nucleus to generate pri-miRNA that is then cleaved by the enzymes Drosha and Pasha to form a pre-miRNA. The pre-miRNA is transported to the cytoplasm through Exportin-5 (XPO5) and cleaved by Dicer-1 (Dcr-1)/Loquacious (loqs) complex to yield miRNA. The miRNA is loaded into the RISC complex, and Ago cleaves the passenger strand of the miRNA and retains the guide strand which guides the active miRISC complex to the target mRNA. Partial complementarity between the guide strand and target mRNA leads to either translation repression or cleavage of the mRNA. miRNAs usually target several genes, with shared sequences in the 3′ untranslated region (UTR). In both pathways siRNAs and miRNAs are amplified by the RNA-dependent RNA polymerase (RdRP). piRNA pathway: The P-element-induced wimpy testis (piwi)-interacting RNA (piRNA) pathway functions in germline cells to protect against transposable elements. Antisense piRNAs are transcribed from repetitive elements in genomic DNA (gDNA) and processed by zucchini (zuc) into 26- to 32-nucleotide primary piRNAs. Primary piRNAs associate with either piwi or aubergine (aub). Piwi-associated piRNAs are translocated to the nucleus, while aub-associated piRNAs cleave cytoplasmic transposon transcripts and trigger a ‘ping-pong’ piRNA amplification. Following transposon, transcript cleavage argonaute-3 (ago3) is loaded with secondary piRNAs which in turn produce piRNAs that associate with aub, resulting in silencing of cytoplasmic transposon transcripts