Coronavirus RNA Synthesis: Transcription
Luis Enjuanes, Isabel Sola, Sonia Zuñiga, and J. L. Moreno
from: Coronaviruses: Molecular and Cellular Biology (Edited by: Volker Thiel). Caister Academic Press, U.K. (2007)
Coronavirus replication involves both viral and cellular proteins, and takes place in the cytoplasm in a membrane-protected microenvironment. Coronaviruses may control the cell machinery by locating some of their proteins in the host cell nucleus, and their replication and transcription possibly require cross-talk between the 5' and 3' ends. Coronavirus transcription involves a discontinuous RNA synthesis (template switch) during the extension of a negative copy of the subgenomic (sg) mRNAs, a process that is controlled by transcription-regulating sequences (TRSs) preceding each gene. The requirement for base pairing during transcription has been formally demonstrated in arteriviruses and coronaviruses. The template switch requires base pairing between the nascent minus RNA strand and the leader TRS with minimum free energy (DG). Coronavirus N proteins have RNA chaperone activity that may help to overcome the energy barrier threshold associated with template switch. The potential role in transcription of selected proteins will be addressed read more ...