Sendai virus

The Sendai virus (SeV) is a member of the Paramyxoviridae family, specifically classified under the genus Respirovirus. It is a negative-sense, single-stranded RNA virus that primarily infects rodents, particularly mice and rats. The virus is named after the city of Sendai in Japan, where it was first isolated.

Virology

The Sendai virus is an enveloped virus with a helical nucleocapsid. Its genome is approximately 15,384 nucleotides in length and encodes six major proteins: the nucleocapsid protein (N), phosphoprotein (P), matrix protein (M), fusion protein (F), hemagglutinin-neuraminidase (HN), and the large protein (L) which is the RNA-dependent RNA polymerase.

Structure

The viral envelope is derived from the host cell membrane and contains the F and HN glycoproteins. The F protein is responsible for mediating the fusion of the viral envelope with the host cell membrane, facilitating viral entry. The HN protein has dual functions: it binds to sialic acid-containing receptors on the host cell surface and possesses neuraminidase activity, which helps in the release of progeny virions from infected cells.

Replication Cycle

The replication cycle of Sendai virus begins with the attachment of the HN protein to sialic acid receptors on the host cell surface. Following attachment, the F protein facilitates the fusion of the viral envelope with the host cell membrane, allowing the viral nucleocapsid to enter the cytoplasm. The viral RNA-dependent RNA polymerase (L protein) transcribes the viral genome into mRNA, which is then translated into viral proteins. The replication of the viral genome occurs in the cytoplasm, and new virions are assembled and bud from the host cell membrane.

Pathogenesis

Sendai virus is a natural pathogen of rodents, causing respiratory infections. In mice, it can lead to pneumonia, characterized by symptoms such as weight loss, ruffled fur, and labored breathing. The virus is highly contagious among rodents but does not typically infect humans.

Applications in Research

Sendai virus is widely used in scientific research due to its ability to induce cell fusion and its role in the development of viral vector systems. It is utilized in the production of induced pluripotent stem cells (iPSCs) because it can deliver reprogramming factors without integrating into the host genome, reducing the risk of insertional mutagenesis.

Also see

• Paramyxoviridae
• Viral replication
• Induced pluripotent stem cell
• Viral vector

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