Molecular characterizations of grass carp (Ctenopharyngodon idella) TBK1 gene and its roles in regulating IFN-I pathway.
TANK-binding kinase 1 (TBK1), a kinase at the crossroads of multiple IFN-inducing signaling pathways, plays essential roles in both antiviral and antibacterial innate immunity in mammals. Here, TBK1 gene (10339bp) was identified and characterized from grass carp Ctenopharyngodon idella (CiTBK1). The genomic sequence is shorter than other orthologs in vertebrate, and a promoter region is found in intron 1. mRNA expression of CiTBK1 was widespread in fifteen tissues investigated, and was up-regulated post GCRV challenge in vivo and in vitro, as well as after stimulation of viral/bacterial PAMPs in vitro. CiTBK1 mediates IFN-I signal pathway through over-expression experiment. Post GCRV challenge, CiTBK1 over-expression inhibits viral infection by induction of CiIFN-I and CiMx1 mainly via CiIRF7. In CiTBK1 over-expression cells, mRNA expressions of CiIRF3, CiIRF7 and CiIFN-I were inhibited, whereas CiMx1 was facilitated after poly I:C stimulation, comparing to those in control group. The result indicated that CiMx1 expression mediated by CiTBK1 is in IFN-I independent way after poly I:C stimulation. However, over-expression of CiTBK1 diminishes LPS-induced expressions of CiIRF3 and CiIRF7 but promotes the induction of CiIFN-I and CiMx1 in comparison with the control, which suggests that CiTBK1-triggered IFN-I activation is in IRF3/IRF7-independent manner after LPS stimulation. Notably, over-expression of CiTBK1 negatively regulated PGN-induced IRF3, IRF7, IFN-I and Mx1 immune response. Taken together, CiTBK1 participates in broad antiviral and antibacterial immune responses in different manners, and keeps regulatory balance that prevents harmful effects from excessive activation.
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling 712100, China.
Xiaoli
X
Feng
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling 712100, China. Electronic address: su.jianguo@gmail.com.
Jianguo
J
Su
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling 712100, China.
Chunrong
C
Yang
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling 712100, China.
Nana
N
Yan
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling 712100, China.
Youliang
Y
Rao
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling 712100, China.
Xiaohui
X
Chen
D000818:Animals; D002347:Carps / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D005393:Fish Diseases / Q000276:immunology; D029941:Fish Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D007370:Interferon Type I / Q000378:metabolism*; D007668:Kidney / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D011070:Poly I-C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D012087:Reoviridae / Q000502:physiology; D012088:Reoviridae Infections / Q000276:immunology / Q000662:veterinary; D015398:Signal Transduction
D029941:Fish Proteins; D007370:Interferon Type I; D017346:Protein Serine-Threonine Kinases; D011070:Poly I-C
Genomic structure; Grass carp (Ctenopharyngodon idella); Grass carp reovirus; IFN-I pathway; Promoter activity; TBK1