Chapter 14B: SARS-CoV-2 and COVID-19 Flashcards
SARS-CoV-2
Severe Acute Respiratory Syndrome Coronavirus-2
Belongs to Coronaviridae
Newly emerging
Highly transmissible
Infecting epithelial and many other types of cells
31 December 2019
Chinese health officials notified WHO of severe cases of an unusual viral pneumonia in Wuhan
7 January 202
Pathogen identified as novel coronavirus
11 February 2020
WHO named COVID-19 and SARS-CoV-2
11 March 2020
WHO declared the outbreak a pandemic
Virion Structure
Large(100-160 nm in diameter) Enveloped Spikes on surface -> crown-like Nucleocapsid: helical symmetry (+) ssRNA genome
Major Structural Proteins
S, E, M, N
S protein
Spike
bind to the host cell through its RBD (receptor-binding domain)
E Protein
Envelope
Help assembly and release virions
M Protein
Membrane
work with E, N, and S; play major role in RNA packaging
N protein
Nucleocapsid
package viral RNA into nucleocapsid
Genome Structure
(+) ssRNA About 30kb 5' cap, 3' poly-A tail 12 ORFs: RdRp, proteases, other NSPs Other ORFs High mutation rate
Anti-receptor
S-protein
Receptor
ACE2 (angiotensin-converting enzyme 2) widely distributed in various tissues
TMPRSS2
facilitate viral entry
Entry and uncoating
Membrane fusion
Endocytosis and then membrane fusion
Translation of ORF1a and ORF1b
(+)RNA-> RdRp, other NSPs
Subgenomic Transcription
(-) RNA -> subgenomic (+)RNAs
Translation
Subgenomic(+)RNAs-> S, M, E at ER; N in cytoplasm
ERGIC
ER-to-Golgi Intermediate Compartment (as budding site
Assembly
nucleocapsid buds into ERGIC with S, M, E -> virion
COVID-19
Coronavirus disease of 2019
COVID-19 progression
- Early infection: no or mild symptoms
- Pulmonary phase: pneumonia and disseminated inflammation
- Hyperinflammation phaseL Acute Respiratory Distress Syndrome, multiorgan failure
