Duplodnaviria

Duplodnaviria_virion_morphology.jpg

Duplodnaviria is a realm of double-stranded DNA viruses that infect a wide range of hosts, including bacteria, archaea, and eukaryotes. This realm is characterized by the presence of a unique major capsid protein (MCP) that forms a distinctive double-jelly roll fold. The name "Duplodnaviria" is derived from the Latin words "duplo," meaning double, and "navis," meaning ship, referring to the double-jelly roll structure of the MCP.

Taxonomy

Duplodnaviria is divided into two major kingdoms:

• Heunggongvirae
• Loebvirae

Heunggongvirae

Heunggongvirae includes viruses that infect eukaryotic cells. The most well-known members of this kingdom are the Herpesvirales, which include the Herpesviridae family. These viruses are known for causing diseases such as herpes simplex, varicella-zoster (chickenpox and shingles), and Epstein-Barr virus (infectious mononucleosis).

Loebvirae

Loebvirae includes viruses that primarily infect prokaryotic cells, such as bacteria and archaea. The most notable order within this kingdom is the Caudovirales, which includes the families Myoviridae, Siphoviridae, and Podoviridae. These viruses are commonly referred to as tailed bacteriophages and are known for their role in horizontal gene transfer and bacterial evolution.

Structure

The defining feature of Duplodnaviria is the double-jelly roll fold of the major capsid protein. This structure is unique to this realm and is crucial for the assembly and stability of the viral capsid. The capsid is typically icosahedral in shape, providing a robust protective shell for the viral genome.

Life Cycle

The life cycle of Duplodnaviria viruses varies depending on the host they infect. In general, the cycle includes the following stages:

• Attachment: The virus attaches to the host cell surface via specific receptors.
• Entry: The viral genome is injected into the host cell.
• Replication: The viral DNA is replicated using the host's machinery.
• Assembly: New viral particles are assembled within the host cell.
• Release: The newly formed viruses are released from the host cell, often causing cell lysis.

Importance

Duplodnaviria viruses play significant roles in various ecosystems. In marine environments, they are crucial in regulating bacterial populations and facilitating nutrient cycling. In medical science, understanding these viruses can lead to the development of novel therapies and vaccines for viral infections.

See Also

• Virus
• Bacteriophage
• Herpesvirus
• Viral replication