Emesvirus

Emesvirus

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Surface view of the MS2 capsid

Emesvirus is a genus of bacteriophages in the family Leviviridae. These viruses specifically infect Escherichia coli and are known for their simple structure and genetic composition. The most well-known species within this genus is the MS2 phage, which has been extensively studied as a model organism in molecular biology.

Structure

Emesviruses are characterized by their small, icosahedral capsids, which are composed of a single type of protein subunit. The capsid encloses a single-stranded RNA genome. The capsid proteins self-assemble into a symmetrical structure, providing protection for the viral RNA.

Genome

Gene map of the MS2 phage

The genome of Emesvirus is a positive-sense single-stranded RNA molecule, approximately 3,569 nucleotides in length. It encodes four proteins: the maturation protein, the coat protein, the lysis protein, and the replicase protein. The genome is organized in a compact manner, with overlapping genes and regulatory sequences that control the expression of the viral proteins.

Life Cycle

The life cycle of Emesvirus begins with the attachment of the phage to the F pilus of an Escherichia coli cell. The viral RNA is then injected into the host cell, where it is translated by the host's ribosomes. The coat protein and replicase are synthesized first, allowing for the replication of the viral RNA. The maturation protein and lysis protein are produced later in the infection cycle. The assembly of new virions occurs in the cytoplasm, and the host cell is lysed to release the progeny phages.

Applications in Research

Emesvirus, particularly the MS2 phage, has been widely used in molecular biology research. It serves as a model system for studying RNA virus replication, translation, and assembly. The simplicity of its genome and life cycle makes it an ideal subject for genetic and biochemical studies. Additionally, MS2 phage display technology has been developed for applications in biotechnology and nanotechnology.

Related Pages

• Bacteriophage
• Leviviridae
• Escherichia coli
• RNA virus