Tectiviridae

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Tectiviridae
Kingdom:	Varidnaviria
Phylum:	Preplasmiviricota
Class:	Tectiliviricetes
Order:	Tectivirales
Family:	Tectiviridae

Tectiviridae is a family of double-stranded DNA viruses that infects bacteria. Members of this family are characterized by their unique virion structure, which includes an icosahedral capsid and an internal lipid membrane. The family Tectiviridae is part of the order Tectivirales and is known for its ability to infect a wide range of bacterial hosts, including those in the genera Bacillus and Enterobacter.

Structure

Tectiviridae virions are non-enveloped and have a distinctive icosahedral capsid with a diameter of approximately 65 nm. The capsid is composed of 12 pentameric capsomers and 20 hexameric capsomers, forming a T=25 lattice. Inside the capsid, there is an internal lipid membrane that surrounds the viral genome. This membrane is derived from the host cell and plays a crucial role in the infection process.

Genome

The genome of Tectiviridae viruses is linear, double-stranded DNA, typically around 15 kilobases in length. The genome encodes for several structural proteins, as well as proteins involved in DNA replication and host cell lysis. The genetic organization is compact, with overlapping open reading frames and the use of both strands of DNA for coding.

Life Cycle

The life cycle of Tectiviridae begins with the attachment of the virion to the host cell surface. This is mediated by specific interactions between the viral capsid proteins and receptors on the bacterial cell surface. Following attachment, the internal lipid membrane of the virion fuses with the host cell membrane, allowing the viral DNA to enter the host cell.

Once inside the host, the viral DNA is transcribed and translated using the host's machinery. The viral genome is replicated, and new virions are assembled in the cytoplasm. The assembly process involves the formation of the capsid around the newly synthesized DNA and the acquisition of the internal lipid membrane. Finally, the host cell is lysed, releasing the mature virions to infect new cells.

Host Range and Ecology

Tectiviridae viruses primarily infect Gram-positive bacteria, with Bacillus species being the most common hosts. However, some members of the family can also infect Gram-negative bacteria, such as Enterobacter. These viruses are found in a variety of environments, including soil, water, and the human gut.

Research and Applications

Tectiviridae viruses are of interest in the study of virus evolution and the mechanisms of virus-host interactions. Their unique structure and life cycle provide insights into the diversity of viral strategies for infection and replication. Additionally, Tectiviridae viruses have potential applications in phage therapy, where they could be used to target and kill specific bacterial pathogens.

Also see

• Bacteriophage
• Virus classification
• Phage therapy
• Icosahedral virus