What is the difference between nucleoprotein and nucleocapsid?

A hallmark of negative-strand RNA viruses (NSVs) is that their genomes never exist as free RNA, but instead are always assembled with many copies of a single nucleoprotein (N) to form highly stable nucleocapsids. Moreover, viral genomes are the only RNAs in infected cells that are assembled with N. The mechanism by which this specific association occurs, for both the segmented (s) and non-segmented (ns) viruses, has recently become clearer due to our expanding knowledge of N protein and nucleocapsid structures.

Highlights

► Structure and function of nucleoproteins of negative-strand RNA viruses. ► Nucleoproteins of the non-segmented viruses are homologous. ► Nucleoproteins of segmented viruses are all different. ► Nucleoproteins of segmented viruses may have two conformations, RNA bound or RNA-free.