Month: September 2022

LARGE DIVERSE GENOMES. “The genomes of Polintons are large by transposon standards, 15–20 kb, and encode arrays of diverse proteins. However, several proteins are shared by all Polintons, including protein-primed type B DNA polymerase (pPolB), RVE family integrase, FtsK-like DNA-packaging ATPase, and an adenovirus-type cysteine protease implicated in the maturation of capsid proteins.” https://lnkd.in/eU7uHHB View in LinkedIn

TWO LIFE FORMS. “Polintons are actually polintoviruses, a novel group of dsDNA viruses that can exist also in the form of transposon-like provirus elements that are integrated with the host genomes and transmitted vertically across host generations.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn

VIRUS-TRANSPOSONS. “Some groups of polintoviruses have lost capsid protein genes and apparently became bona fide transposons, for which the name polintons can be retained. Polintoviruses are the second major group of eukaryotic dsDNA viruses, after the “Megavirales,” that is represented in widely diverse unicellular eukaryotes along with many animals.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn

WIDESPREAD. “Polintons/polintoviruses are missing in only one of the five major eukaryotic superkingdoms, namely Archaeplastida, which includes land plants as well as red and green algae.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn

CENTRAL HUB. “Polintoviruses share homologous genes and gene blocks with many other viruses, transposons, and plasmids. In the network of evolutionary connections between all these groups of mobile elements where the edges are homologous genes, Polintoviruses represent the central hub that shares the maximum number of genes with other nodes.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn

ORIGIN OF MITOCHONDRION. “Polintoviruses appear to have evolved from bacteriophages of the family Tectiviridae, at the onset of eukaryogenesis. This ancestral tectivirus most likely entered the protoeukaryotic cell along with the α-proteobacterial endosymbiont that subsequently gave rise to the mitochondrion.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn

EXTREME STREAMLINING. “Some polintoviruses have given up the virus lifestyle altogether by losing the genes involved in virion formation and becoming pure transposons (Polintons). A striking example is the extraordinary expansion of capsid-less Polintons in Trichomonas vaginalis, where they constitute up to 30% of the host genome.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn

ALTERNATIVE STRATEGY. “Adenoviruses followed the opposite evolutionary route, losing the integrase gene together with the integration/transposition ability and thereby committing to a strictly viral reproduction strategy.” https://lnkd.in/eU7uHHB View in LinkedIn

CREATION OF SSDNA VIRUSES. “Polintoviruses also contributed the pPolB gene to the evolution of a remarkable family of ssDNA viruses, the Bidnaviridae, which emerged as a result of extensive gene shuffling between four groups of selfish elements.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn

CREATION OF MEGAVIRALES. “Polintoviruses seem to have played a key role in the emergence of the “Megavirales,” the most abundant and diverse group of eukaryotic dsDNA viruses.” http://onlinelibrary.wiley.com/doi/10.1111/nyas.12728/full View in LinkedIn