Intrinsic host restriction factors of human cytomegalovirus replication and mechanisms of viral escape

作     者：Santo Landolfo Marco De Andrea Valentina Dell'Oste Francesca Gugliesi 

作者机构：Department of Public Health and Pediatric Sciences Laboratory of Pathogenesis of Viral InfectionsUniversity of Turin 

出 版 物：《World Journal of Virology》 (世界病毒学杂志)

年 卷 期：2016年第5卷第3期

页      面：87-96页

学科分类：10[医学] 

基　　金：Supported by Italian Ministry of Education,University and Research--MIUR(PRIN 2012)to S.Landolfo(2012SNMJRL)and V.Dell’Oste(20127MFYBR) University of Turin,Research Funding 2014 to S.Landolfo,M.De Andrea,and V.Dell’Oste Regione Piemonte to S.Landolfo(PAR-FCS 2007/2013) 

主　　题：Human cytomegalovirus Intrinsic immunity Restriction factors Viral escape mechanisms DNA sensors 

摘      要：Before a pathogen even enters a cell, intrinsic immune defenses are active. This first-line defense is mediated by a variety of constitutively expressed cell proteins collectively termed restriction factors(RFs), and they form a vital element of the immune response to virus infections. Over time, however, viruses have evolved in a variety ways so that they are able to overcome these RF defenses via mechanisms that are specific for each virus. This review provides a summary of the universal characteristics of RFs, and goes on to focus on the strategies employed by some of the most important RFs in their attempt to control human cytomegalovirus(HCMV) infection. This is followed by a discussion of the counter-restriction mechanisms evolved by viruses to circumvent the host cell s intrinsic immune defenses. RFs include nuclear proteins IFN-γ inducible protein 16(IFI16)(a Pyrin/HIN domain protein), Sp100, promyelocytic leukemia, and h Daxx; the latter three being the keys elements of nuclear domain 10(ND10). IFI16 inhibits the synthesis of virus DNA by downregulating UL54 transcription- a gene encoding a CMV DNA polymerase; in response, the virus antagonizes IFI16 via a process involving viral proteins UL97 and pp65(p UL83), which results in the mislocalizing of IFI16 into the cytoplasm. In contrast, viral regulatory proteins, including pp71 and IE1, seek to modify or disrupt the ND10 proteins and thus block or reverse their inhibitory effects upon virus replication. All in all, detailed knowledge of these HCMV counter-restriction mechanisms will be fundamental for the future development of new strategies for combating HCMV infection and for identifying novel therapeutic agents.