''Bartonegtaviriform'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

viriform Virus classification is the process of naming viruses and placing them into a taxonomic system similar to the classification systems used for cellular organisms. Viruses are classified by phenotypic characteristics, such as morphology, nucleic ...

s in the family Bartogtaviriformidae. It includes one species: ''Bartonegtaviriform andersoni'' (BaGTA), which is a gene transfer agent, found within bacteria of the genus ''

Bartonella ''Bartonella'' is a genus of Gram-negative bacteria. It is the only genus in the family Bartonellaceae. Facultative intracellular parasites, ''Bartonella'' species can infect healthy people, but are considered especially important as opportuni ...

''.

Name

The family name, Bartogtaviriformidae'','' is a

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

of ''Barto'', from "host" ''Bartonella'', ''gta'' from gene transfer agent and ''viriformidae'', the fact that it is a viriform. The genus name, ''Bartonegtaviriform,'' is a combination of ''Bartone'', from "host" ''Bartonella'', ''gta'' from gene transfer agent and viriform, the fact that it is a viriform. The species name, ''andersoni'' is named after GTA researcher Burt Anderson, who first discovered BaGTA particles.

Gene transfer agents

GTAs can be considered as a form of “domesticated”

prophage A prophage is a bacteriophage (often shortened to "phage") genome that is integrated into the circular bacterial chromosome or exists as an extrachromosomal plasmid within the bacterial cell (biology), cell. Integration of prophages into the bacte ...

—that is, ancestrally derived from a

bacteriophage A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived . Bacteriophages are composed of proteins that Capsid, encapsulate a DNA or RNA genome, and may have structu ...

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

, but altered by the host to confer an adaptive benefit—and thus represent one of many

phage A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived . Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures tha ...

-derived adaptive functions observed in bacterial genomes.

Phylogeny

Genomic sequence analysis revealed that all bacteria of the genus ''Bartonella'' are characterized by the presence of a ''Bartonella''-specific GTA (BaGTA), which shares no homologies to previously described GTA systems. BaGTA is encoded upstream from an origin of run-off replication (ROR), another conserved feature of ''Bartonella'' genomes that has been suggested to be linked to BaGTA activity. Phylogenetic analyses identified BaGTA as a key innovation associated with the adaptive radiation that characterizes these

zoonotic A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a virus, bacterium, parasite, fungi, or prion) that can jump from a non-human vertebrate to a human. When h ...

bacterial pathogens. Although BaGTA is not directly linked to Bartonella pathogenicity, it has been proposed to drive the exchange and the diversification of host-interaction factors within Bartonella communities such as VirB type IV secretion system ( T4SS) and its cognate Bartonella effector proteins. Maintenance of BaGTA is likely driven by selection to increase the likelihood of genetic exchange and facilitates adaptation to host-specific defense systems during infection.

Role

Despite clear genomics-based arguments pointing to a central role for BaGTA in ''Bartonella'' biology, direct experimental evidence for its activity are scarce and the molecular mechanisms underlying its activity and regulation remain elusive.

Genome

BaGTA particles are larger than RcGTA and contain 14 kb

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

fragments. Although this capacity could in principle allow BaGTA to package and transmit its 14 kb GTA cluster, DNA coverage measurements show reduced coverage of the cluster. An adjacent region of high coverage is thought to be due to local DNA replication.

References

Virus genera {{virus-stub