Genetic characterizations of Toll‐like receptors in the brown rat and their associations with pathogen infections. Issue 5 (8th June 2021)

• Record Type: Journal Article
• Authors: SU, Qianqian; CHEN, Yi; WANG, Bo; ZHANG, Qingxun; HE, Hongxuan
• Is Part Of: Integrative zoology. Volume 17:Issue 5(2022)
• Page Start: 879
• Page End: 889
• Publication Date: 2021-06-08
• Subjects: Bartonella -- brown rats -- hepatitis E virus -- polymorphism -- susceptibility -- Toll‐like receptors; Zoology -- Periodicals; Animals -- Periodicals; Zoologie -- Périodiques; Animaux -- Périodiques; 590.5
• DOI: 10.1111/1749-4877.12555
• Languages: English
• ISSNs: 1749-4869

Abstract

Abstract: Toll‐like receptors (TLRs) are important initiators of innate immune responses that target host–pathogen interactions. However, further research into the molecular characteristics of TLRs in wild populations is required, as well as how TLRs genetically influenced pathogen infections in the brown rat ( Rattus norvegicus ). Here, we explored the genetic characterization and evolution of 2 sensing nucleic acid TLRs (TLR7 and TLR8) and 2 sensing non‐nucleic acid TLRs (TLR2 and TLR4) in the wild brown rat, and assessed their associations with 2 RNA viruses (Seoul hantavirus and rat hepatitis E virus (HEV)) and 2 bacteria ( Leptospira and Bartonella ). In these 4 TLRs, we discovered a total of 16 variants. Furthermore, TLR8 had high genetic diversity among 7 variants, while TLR2 had low genetic diversity with only 1 variant. According to selective pressure analyses, TLR4, TLR7, and TLR8 genes evolved under purifying selection. Interestingly, significant associations were found between 3 TLR8 variants and HEV infection, as well as 1 TLR2 variant and Bartonella infection. Overall, our findings provided a glimpse into the genetic characterization of TLRs in the brown rat, and further demonstrated that TLR2 and TLR8 genetic variations were related to Bartonella and HEV infection, respectively. Especially, TLR8 may be a good candidate immune gene for future research on molecular ecology and functional adaptation in wild populations. Abstract : TLR8 had the higher genetic diversity, whereas TLR2 had the lower genetic diversity in brown rats. TLR4, TLR7, and TLR8 genes tended to evolve under purifying selection in brown rats. Significant associations were detected between 3 TLR8 polymorphic sites and HEV infection, as well as 1 TLR2 polymorphic site and Bartonella infection in brown rats.