Fig. 1

TLR7 is expressed by peri-neuronal support cells in mouse sensory ganglia. A Mouse-specific TLR7 in situ hybridization probe was tested in wild-type and TLR7 KO mouse spleen. TLR7 (pink) was detected in the spleen from wild-type mice, but not in TLR7 KO mice, confirming the specificity of the probe. The housekeeping gene Ppib (pink) was used as a positive control to confirm tissue permeability and RNA integrity, and an in situ probe for the bacterial protein DapB served as a negative control to assess the in situ hybridization background signal. B TLR7 in situ probes labeled small cells located in close proximity to neuronal cell bodies (N) within dorsal root ganglia and vagal ganglia in wild-type mice. Rarely, a single TLR7 in situ probe signal could be found in a neuronal cell body (N*). TLR7 was absent in both dorsal root and vagal ganglia from TLR7 KO mice. Vagal ganglia were also labeled with in situ hybridization probes targeting lacZ since TLR7 KO mice were generated by inserting an E. coli lacZ gene into exon 3 of the mouse TLR7 gene. LacZ in situ probes labeled small support cells, but not neurons in vagal ganglia from TLR7 KO mice. Blue = hematoxylin nuclear stain in all images. N = 4, representative images are shown. Scale bar = 50 μm