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. Author manuscript; available in PMC: 2017 Jul 13.
Published in final edited form as: Cell Host Microbe. 2016 Jun 30;20(1):91–98. doi: 10.1016/j.chom.2016.06.001

Figure 4. Ixodes JAK-STAT signaling cascade controls expression of IGTPase and regulates the expression of the borreliacidal peptide, Dae2.

Figure 4

(A) B. burgdorferi-infection induced transcript levels of potential I. scapularis genes encoding potential antimicrobial peptides. Bars represent fold changes ± SEM (20 ticks) of the target transcript levels in 48-hour fed ticks that parasitized on B. burgdorferi-infected mice relative to naive hosts. Accession numbers: (1) AAV63544, (2) ISCW006596, (3) ISCW022102, (4) ISCW005928, (5) ISCW016466, (6) ISCW016747, (7) ISCW018425, (8) ISCW002331, (9) ISCW002695, (10) ISCW018541, (11) ISCW001310, (12) ISCW017494, (13) ISCW014204, (14) ISCW009364.

(B) IGTPase deficiency results in the dramatic reduction of Dae2 transcripts. Ticks were microinjected with IGTPase dsRNA or GFP dsRNA and allowed to parasitize B. burgdorferi-infected mice. After feeding, ticks transcript levels of SP10, Dae2, and defensin were individually measured in 10 nymphs in each group by qRT-PCR normalized against tick β-actin. The bars represent the mean ± SEM values from 10 individual ticks. **p < 0.01; * p < 0.05.

(C) Reduced phosphorylated I. scapularis STAT in ticks engorged on IFNγ knockout mice. Fed ticks were analyzed for phosphorylated I. scapularis STAT levels by immunoblotting. Equal protein loading was evidenced by Ponceau S staining.

(D) Silencing of STAT transcripts via RNA interference. Nymphal ticks (25/group) were injected with STAT dsRNA or control GFP dsRNA, fed on mice, and processed for transcript silencing. The bars represent the mean ± SEM values. *, p < 0.001.

(E) STAT knockdown affects expression of IGTPase transcripts. Groups of 25 control and STAT-silencing ticks were examined for expression of IGTPase transcripts via qRT-PCR. *p < 0.01.

(F) Expression of antimicrobial peptide Dae2 is severely impaired in STAT knockdown ticks. Groups of 25 control and STAT-silencing ticks were examined for Dae2 transcript levels via qRT-PCR. *p < 0.01.