Peploviricota

Peploviricota is a phylum of viruses that belong to the Baltimore classification Group I, which consists of double-stranded DNA viruses. This phylum is characterized by its members having a lipid envelope, which is derived from the host cell membrane during the viral replication process. The name "Peploviricota" is derived from the Greek word "peplos," meaning "envelope," reflecting this key feature.

Characteristics

Peploviricota viruses are known for their enveloped virions, which are typically spherical or pleomorphic in shape. The envelope is studded with viral glycoproteins that play crucial roles in host cell recognition and entry. These viruses have a double-stranded DNA genome, which is replicated in the host cell nucleus or cytoplasm, depending on the specific virus.

Genome

The genome of Peploviricota viruses is composed of linear double-stranded DNA. The size of the genome can vary significantly among different members of the phylum, ranging from a few kilobases to over 200 kilobases. The genome encodes for various structural and non-structural proteins, including those involved in DNA replication, transcription, and virion assembly.

Replication Cycle

The replication cycle of Peploviricota viruses involves several key steps:

1. Attachment and Entry: The virus attaches to specific receptors on the host cell surface via its glycoproteins. Following attachment, the virus enters the cell through endocytosis or membrane fusion.
2. Uncoating: Once inside the host cell, the viral capsid is disassembled, releasing the viral DNA into the host cell's nucleus or cytoplasm.
3. Replication and Transcription: The viral DNA is replicated using the host cell's machinery. Transcription of viral genes occurs, leading to the production of viral mRNA.
4. Translation and Assembly: Viral proteins are synthesized in the host cell cytoplasm. These proteins are then transported to the site of assembly, where new virions are assembled.
5. Budding and Release: Newly formed virions acquire their envelope by budding through the host cell membrane, incorporating host-derived lipids and viral glycoproteins. The mature virions are then released to infect new cells.

Taxonomy

The phylum Peploviricota is divided into several classes, including:

• Tectiliviricetes: This class includes viruses with icosahedral capsids and a lipid envelope.
• Chitoviricetes: This class is characterized by viruses with complex capsid structures and unique replication strategies.

Pathogenesis

Peploviricota viruses are known to infect a wide range of hosts, including humans, animals, and plants. Some members of this phylum are associated with significant diseases in humans, such as herpesviruses, which can cause conditions ranging from cold sores to more severe diseases like encephalitis.

Research and Applications

Research on Peploviricota viruses has led to significant advancements in understanding viral pathogenesis, immune evasion, and vaccine development. These viruses are also used in gene therapy and as vectors for delivering therapeutic genes due to their ability to efficiently enter host cells and deliver genetic material.

Also see

• Virus classification
• Baltimore classification
• Viral replication
• Herpesviridae

Virus classification

Diagram of a virus structure