Figure 4.

Host proteins and the coronavirus life cycle. Virus particle attaches onto the host cell via cellular receptors on the surface and enters. Entry is followed by the uncoating of the ribonucleocapsid to expose the positive-sense genomic RNA which is translated by the host ribosomes to yield the viral replication complex. The viral replication complex continues with viral transcription and genome replication and, with the aid of host proteins such as hnRNPA1, yields a nested set of positive-sense sub-genomic sized mRNAs as well as the full-length virus genome. Sub-genomic sized mRNAs are translated by host ribosomes into viral structural (S, E, M, N) and accessory proteins. The N protein packages the positive-sense genomic RNA into a ribonucleocapsid and is assembled into the virus particles with the help of β-actin. The newly formed virus particles undergo maturation when passing through the Golgi and exit the host cell via exocytosis.