The Evolutionary Of Chemokine XCL1 And Its Receptor XCR1 In Murine

Chemokines are a class of cytokines that control the directed migration of cells.In immune response,the interaction of chemokines with their receptors triggers the intracellular signal responses,and consequently promotes the directional migration of cells and a series of physiological processes.The chemokine XCL1 specifically binds to its receptor XCR1,consequently inducing migration of immature dendritic cells(DCs),effector T cells,and B cells,which play important role in DC cell-mediated antigen cross-presentation.Although there is a preliminary understood of the structure and function about chemokines and their receptors,the escape mechanisms for their response to pathogenic microorganisms remains to be further studied.In this experiment,the evolutionary characteristics of XCL1 and XCR1 were studied to provide clues to explain their recognition-evasion competition between host and pathogenic microorganisms.In order to clearly characterize the genetic variation of chemokine XCL1 and its receptor XCR1,we collected and analyzed the coding sequences of XCL1 and XCR1 from several subfamilies of Murinae.In addition,in order to reveal the evolutionary characteristics of these two genes in different stages,we determined the intraspecific genetic variation of Mus musculus and Rattus norvegicus.On this basis,we analyzed the evolutionary characteristics of XCL1 and its receptor XCR1 gene in Murinae by using evolutionary genetics and structural simulation methods.The main results are as follows:1)XCL1 and XCR1 genes maintain a relatively conserved genetic structure in Murinae.The coding sequences length of XCL1 in 14 species of the Murinae was 345 bp,and the coding sequences length of XCR1 ranges from 1017 bp to 1020 bp.2)XCL1 and XCR1 have the characteristics of rapid evolution in Murinae.3)Based on the population data of Mus musculus and Rattus norvegicus,the results showed that both XCL1 and XCR1 genes were affected by recent adaptive evolution.4)In the evolution of Murinae,three amino acid of XCL1 were affected by positive selection,which sites 79 and 94 were located in alpha helix and C-terminus.Five amino of XCR1 were affected by positive selection,which site 36 was located in the N-terminus,site 185,187 and 270 were located in the extracellular loops,site 255 was located in the sisth transmembrane helixe,site 308 was located in the C-terminus.The distribution of the identified amino acids in the proteins suggests that they play an important role in the structure and function of XCL1 and XCR1.Based of molecular evolution,the present study revealed the evolution of XCL1 and XCR1 in Murinae,and explored their evolutionary characteristics.Our results shed inside into the their structure,function,and interaction Mechanism.