Month: September 2022

MOVING TARGET. “Viruses possess signature genes, such as those encoding capsid protein, that provide for assignment of novel genomes to a particular family of viruses even in the absence of close relatives. The flip side of the coin is that viruses typically evolve much faster than cellular life forms so that finding homologs of virus genes is often challenging.” https://lnkd.in/dyavu7e View in LinkedIn

NEW FIELD. “Virus metagenomics is a young research direction but can already boast several stories of conspicuous success in the discovery of novel groups of (putative) viruses with unexpected features.” https://lnkd.in/dyavu7e View in LinkedIn

NEW SPECIES IDENTIFICATIONS. “Among the most notable ones is the identification of the class of chimeric single-stranded (ss) DNA viruses that combine genes from known families of positive-strand RNA viruses and ssDNA viruses.” https://lnkd.in/dyavu7e View in LinkedIn

ADVANCES. “These findings have substantially enriched the available collection of ssDNA virus genomes, but more importantly, have changed the existing picture of the evolution of this class of viruses.” https://lnkd.in/dyavu7e View in LinkedIn

POLINTONS IN PLAIN VIEW. “An equally spectacular discovery of metagenomics is the identification of a novel bacteriophage that is more abundant than any other phage in the human gut but has remained unnoticed until metagenome mining has become highly efficient.” https://lnkd.in/dyavu7e View in LinkedIn

THE LARGEST. “Polintons are large (genomes of 15 to 20 kb, the largest among the eukaryotic transposons), self-replicating transposable elements that are integrated into the genomes of diverse unicellular and multicellular eukaryotes in highly variable numbers of copies.” https://lnkd.in/dyavu7e View in LinkedIn

POLYMERASE INTEGRONS. “All Polintons encode a protein-primed DNA polymerase and a retrovirus-like integrase (hence the name of these elements: POLINTons). The majority of Polintons also encode a homolog of the DNA-packaging ATPase and maturation protease that are characteristic of diverse double-stranded (ds) DNA viruses.” https://lnkd.in/dyavu7e View in LinkedIn

TRANSITIONAL FORM. “Thus, Polintons have been often considered virus-like transposons although no structural proteins have been initially detected.” https://lnkd.in/dyavu7e View in LinkedIn

STRUCTURAL PROTEINS. “Most of the Polintons encode putative major and minor capsid proteins (MCP and mCP, respectively).” https://lnkd.in/dyavu7e View in LinkedIn

STRUCTURAL CLUES. “MCP and mCP respectively adopt intact double and single jelly-roll folds, strongly suggesting that Polintons are capable of forming virions.” https://lnkd.in/dyavu7e View in LinkedIn