Viruses and the placenta: the essential virus first view

  title={Viruses and the placenta: the essential virus first view},
  author={Luis P. Villarreal},
  pages={20 - 30}
A virus first perspective is presented as an alternative hypothesis to explain the role of various endogenized retroviruses in the origin of the mammalian placenta. It is argued that virus–host persistence is a key determinant of host survival and the various ERVs involved have directly affected virus–host persistence. 

Viruses, cancer and non-self recognition

This review is aimed at looking at the balance between the host and persistent viruses with a focus on the immune system, and indicates that viral and cancer strategies appear different.

MHC Class I Regulation: The Origin Perspective

This review brings forward the viral-mediated aspects of the origin and evolution of adaptive immunity and aims to link this perspective with the MHC class I regulation.

Beyond cells – The virome in the human holobiont

A look at the scientific and technological developments that led to the advent of viral and bacterial metagenomics with a particular, but not exclusive, focus on human viromics from an ecological perspective.


The virocell concept states that viruses are cellular organisms and emphasizes their ability to produce their own genes, and the definition of life and living organisms remains challenging.

Viruses in the 21st Century: From the Curiosity-Driven Discovery of Giant Viruses to New Concepts and Definition of Life.

  • P. Forterre
  • Biology
    Clinical infectious diseases : an official publication of the Infectious Diseases Society of America
  • 2017
This story emphasizes the power of multidisciplinary curiosity-driven research, from the hospital to the field and the laboratory, and how several other lines of research in virology converged during the last 2 decades to change traditional perception of the viral world.

To the End of Dogmatism in Molecular Biology

This contribution adds several aspects which Nobel’s article does not explicitly mention, providing some examples for a better understanding of evolutionary novelty.

Social Networking of Quasi-Species Consortia drive Virolution via Persistence

The emergence of cooperative quasi-species consortia (QS-C) thinking from the more accepted quasispecies equations of Manfred Eigen, provides a conceptual foundation from which concerted action of

Transposable elements: Self‐seekers of the germline, team‐players of the soma

  • D. Haig
  • Biology
    BioEssays : news and reviews in molecular, cellular and developmental biology
  • 2016
The germ track is the cellular path by which genes are transmitted to future generations whereas somatic cells die with their body and do not leave direct descendants, so the performance of most bodily functions by a sequestered soma reduces organismal costs of TEs.



On viruses, sex, and motherhood

The participation of retroviruses in the immunosuppression by the embryo and the evolution of placental orders is considered.

Retrovirus restriction factors.

Host Susceptibility to endogenous viruses: defective, glycoprotein-expressing proviruses interfere with infections

Three defective endogenous avian leukosis viruses, ev3, ev6 and ev9, interfered with subgroup E virus infections, and ev3 and ev6 protected chickens and cultured cells from subgroupE virus infections.

Virus-host symbiosis mediated by persistence.

This review focuses on the relationship between persisting viruses and their host, and mechanisms of persistence that involve addiction (toxin/antitoxin) strategies are presented with respect to viral defense.

Discovery of Retroviral Homologs in Bats: Implications for the Origin of Mammalian Gammaretroviruses

An analysis of the similarity in the phylogenetic history between the gammaretroviruses and their bat hosts provided evidence for both host-virus codivergence and cross-species transmission.

Placental endogenous retrovirus (ERV): structural, functional, and evolutionary significance

  • J. Harris
  • Biology
    BioEssays : news and reviews in molecular, cellular and developmental biology
  • 1998
The hypothesis that one or more ancient trophoblastic ERVs could have played a role in the evolution and divergence of all placental mammals is evaluated.

Small non-coding RNAs, mammalian cells, and viruses: regulatory interactions?

Comment on several lines of evidence that support the concept that mammalian cells can use small non-coding RNAs (ncRNA) to regulate physiological viral infections and how viruses may in turn protect, suppress, evade, modulate, or adapt to the host cell's ncRNA regulatory schema.

A Paradigm for Virus–Host Coevolution: Sequential Counter-Adaptations between Endogenous and Exogenous Retroviruses

It is strongly suggested that endogenization and selection of ERVs acting as restriction factors is a mechanism used by the host to fight retroviral infections.

From Viruses to Genes: Syncytins

How close are the viral and animal genome worlds and, focusing mainly on the hominoid ERVWE1 locus encoding Synctin-1, how the different proviruses encoding Syncytins have been domesticated to achieve placental functions is illustrated.