The nonstructural protein 2C of Coxsackie B virus has RNA helicase and chaperoning activities

RNA-remodeling proteins,including RNA helicases and chaperones,play vital roles in the remodeling of structured RNAs.During viral replication,viruses require RNA-remodeling proteins to facilitate proper folding and/or re-folding the viral RNA elements.Coxsackieviruses B3(CVB3)and Coxsackieviruses B5(CVB5),belonging to the genus Enterovirus in the family Picornaviridae,have been reported to cause various infectious diseases such as hand-foot-and-mouth disease,aseptic meningitis,and viral myocarditis.However,little is known about whether CVB3 and CVB5 encode any RNA remodeling proteins.In this study,we showed that 2C proteins of CVB3 and CVB5 contained the conserved SF3 helicase A,B,and C motifs,and functioned not only as RNA helicase that unwound RNA helix bidirectionally in an NTP-dependent manner,but also as RNA chaperone that remodeled structured RNAs and facilitated RNA strand annealing independently of NTP.In addition,we determined that the NTPase activity and RNA helicase activity of 2C proteins of CVB3 and CVB5 were dependent on the presence of divalent metallic ions.Our findings demonstrate that 2C proteins of CVBs possess RNA-remodeling activity and underline the functional importance of 2C protein in the life cycle of CVBs.

Enterovirus 713C proteolytically processes the histone H3 N-terminal tail during infection

Dear Editor,Enterovirus 71(EV71)belongs to the genus Enterovirus,family Picornaviridae(Oberste et al.,1999).It was first isolated from patients with central nervous system diseases in California between 1969 and1974(Schmidt et al.,1974)and has spread worldwide(Solomon et al.,2010).EV71 infection usually causes mild,self-limiting hand,foot,and mouth disease in children.Acute EV71 infection may also cause severe polio-like neurological diseases and significant mortality.