Chapter category: Viruses
Encapsidation of the Segmented Double-Stranded RNA Genome of Bacteriophage PHI 6
Viral Genome Packaging Machines: Genetics, Structure
and Mechanism
Edited by: Carlos CatalanoISBN: 0-306-48227-4
» Get more information about this book at landesbioscience.com «
Chapter authors:
Minna M. Poranen, Markus J. Pirttimaa and Dennis H. Bamford
Bacteriophage PHI6 has a segmented double-stranded RNA genome that is incorporated into a preformed capsid during the viral assembly. The three viral genomic segments are packaged as single-stranded precursors, which are later replicated into the mature double-stranded genome inside the capsid by the viral polymerase. The packaging efficiency of PHI6 is high; virtually all particles released from PHI6-infected cells are infectious and carry one copy of each of the genome segments. This feature makes PHI6 an appropriate model to analyze the principles of packaging of a multi-segmented genome. In vitro analyses have revealed that the packaging of PHI6 involves sequential uptake of the three genome segments. The initiation of RNA replication is a checkpoint for correct genome packaging and is dependent on a specific interaction between the viral RNA and the preassembled polymerase complex, the procapsid. During the maturation the polymerase complex undergoes structural changes which lead to the expansion of the particle. The packaging NTPase of PHI6 is a ring-like hexamer that is located at each of the five-fold vertices in the procapsid. However, it appears that only one vertex is adequate to carry out efficient packaging, while the others are required when the newly synthesized message RNAs exits from the capsid. PHI6 packaging and replication shares features with bacterial double-stranded DNA viruses as well as with eukaryotic double-stranded RNA viruses.
Additional chapters from this book:
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Encapsidation of the Segmented Double-Stranded RNA Genome of Bacteriophage PHI 6
Minna M. Poranen, Markus J. Pirttimaa and Dennis H. Bamford
Bacteriophage PHI6 has a segmented double-stranded RNA genome that is incorporated into a preformed capsid during the viral assembly. The three viral genomic segments are packaged as single-stranded...
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During formation of a mature bacteriophage particle, a procapsid of protein packages the linear double-stranded DNA genome of the related bacteriophages, T3 and T7. Initiation of T3/T7 DNA packaging...
