The hub protein loquacious connects the microRNA and short interfering RNA pathways in mosquitoes.
Bottom Line: Conversely, Loqs-PB alone interacted with mosquito dicer-1 and was essential for full miRNA production.Mosquito Loqs interacted with both argonaute 1 and 2 in a manner independent of its interactions with dicer.We conclude that the functional specialization of Loqs-PD in Drosophila is a recently derived trait, and that in other dipterans, including the medically important mosquitoes, Loqs-PA participates in both the miRNA and endo-siRNA based pathways.
Affiliation: Fralin Life Science Institute and Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA.Show MeSH
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Mentions: To further explore the relationships of Ae. aegypti R2D2, Loqs-PA and Loqs-PB to siRNA and miRNA factors, we employed co-immunoprecipitation (co-IP) assays to test for protein–protein interactions between each dsRBP and Dcr1, Dcr2, Ago1 and Ago2. As both the Drosophila (Loqs) and human (TRBP) orthologs of Ae. aegypti Loqs have been shown to bind Dcr1 through an interaction mediated by the 3rd DRM at the C-terminus of the protein (19,32), two deletion constructs were included with a truncation immediately preceding the third DRM (Δ258) or immediately following the second DRM (Δ226) (Figure 3A). Co-IP experiments confirmed a strong association between R2D2 and Dcr2; this interaction was not affected by pre-treatment with RNaseA and is consistent with the role of this protein in the siRNA pathway (Figure 3B). Likewise, only Loqs-PB interacted with DCR1, consistent with its role in miRNA biogenesis. Interestingly, both Loqs-PA and Loqs-PB interacted with Dcr2, Ago1 and Ago2. Deleting the third DRM had no effect on the interaction between Loqs and Ago proteins. However, this interaction was lost when the 32 a.a. spacer separating the 2nd and 3rd DRMs was deleted (Figure 3B). Neither deletion had any effect on the ability of Loqs to interact with Dcr2.
Affiliation: Fralin Life Science Institute and Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA.