A versatile building block:the structures and functions of negative-sense single-stranded RNA virus nucleocapsid proteins

Nucleocapsid protein(NPs)of negative-sense single-stranded RNA(-ssRNA)viruses function in different stages of viral replication,transcription,and maturation.Structural investigations show that-ssRNA viruses that encode NPs preliminarily serve as structural building blocks that encapsidate and protect the viral genomic RNA and mediate the interaction between genomic RNA and RNA-dependent RNA polymerase.However,recent structural results have revealed other bio-logical functions of-ssRNA viruses that extend our understanding of the versatile roles of virally encoded NPs.