Fig. 1
(Parts BÂ and CÂ are reproduced from [51] with permission from Elsevier)
Mechanism of coronavirus (CoV) entry into target cells. A Coronaviruses bind to receptors on the host cell’s surface and enter the cell through endocytosis or fusion (1). The virus RNA genome is translated (2) to make polyproteins that are simultaneously broken down by proteases encoded in the polyprotein to produce RdRp complex components (3). In the following steps, (−Sense) subgenomic transcription and RNA replication (4) and (+Sense) subgenomic transcription and RNA replication (5) happen. The subgenomic mRNAs are translated into structural and accessory proteins (6). The positive-sense genomic RNA is bound by nucleocapsid and buds into the ERGIC studded with S, E, and M proteins (steps 6 and 7). The enveloped virion is exported from the cell by exocytosis (steps 8 and 9). SARS-CoV-2 particles in a B endothelial cell and a C type II pneumocyte at high magnification acquired by electron microscopy (black arrows refer to well-preserved coronavirus)