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Frontiers in veterinary science2021; 8; 693416; doi: 10.3389/fvets.2021.693416

Differential Expression Pattern of Retroviral Envelope Gene in the Equine Placenta.

Abstract: Endogenous retroviruses (ERVs) are proviral phases of exogenous retroviruses, which have coevolved with vertebrate genomes for millions of years. The conservation of ERV genes throughout evolution suggests their beneficial effects on their hosts' survival. An example of such positive selection is demonstrated by the syncytin gene, which encodes a protein with affinity for various mammalian placentas that is involved in the formation of syncytiotrophoblasts. Although the horse has an epitheliochorial placenta, in which the fetal trophoblasts are simply apposed to the intact uterine epithelium, we have previously demonstrated that the equine ERV (EqERV) RNA is unexpectedly expressed in placental tissue. In the present study, we investigated the mRNA expression pattern of the EqERV gene in different parts of the equine placenta, to gain more insight into its putative role in the fetal-maternal relationship. To this end, we used reverse transcription-quantitative PCR (RT-qPCR) and hybridization assays to analyze different target areas of the equine placenta. The retroviral gene is expressed in the equine placenta, even though there is no syncytium or erosion of the uterine endometrium. The gene is also expressed in all the sampled areas, although with some quantitative differences. We suggest that these differences are attributable to variations in the density, height, and degree of morphological complexity of the chorionic villi forming the microcotyledons. The involvement of the EqERV gene in different functional pathways affecting the fetus-mother relationship can be hypothesized.
Copyright © 2021 Stefanetti, Pascucci, Wilsher, Cappelli, Capomaccio, Reale, Passamonti, Coletti, Crociati, Monaci and Marenzoni.
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Publication Date: 2021-07-09 PubMed ID: 34307531PubMed Central: PMC8298818DOI: 10.3389/fvets.2021.693416Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study is about the investigation of the expression patterns of the EqERV gene, a type of endogenous retrovirus, in different parts of the horse placenta. The researchers hypothesize that this gene might have a role in the equine fetal-maternal relationship.

Understanding Endogenous Retroviruses (ERVs)

  • ERVs are remnants of exogenous retroviruses. They have integrated into the genome of vertebrate species, co-evolving with them for millions of years.
  • The fact that ERVs have been conserved over evolutionary time suggests they have been beneficial for the survival of their host species.
  • A well-known example of a beneficial ERV gene is the syncytin gene. It codes for a protein that interacts with the placental tissue in various mammals, playing a critical role in the formation of syncytiotrophoblasts, which are important structural elements in the placenta.

The EqERV Gene and the Equine Placenta

  • The horse placenta is epitheliochorial, meaning the fetal tissue (the trophoblasts) is situated directly next to the intact uterine lining (the endometrium).
  • Despite this structure of the equine placenta, which does not involve the formation of syncytiotrophoblasts, the researchers have previously found expression of the equine ERV (EqERV) gene in this tissue.
  • This led the team to investigate the RNA expression pattern of this gene in varying parts of the equine placenta to understand its potential role in the relationship between fetus and mother in equine species.

Study Methodology

  • The team used reverse transcription-quantitative PCR (RT-qPCR) and hybridization techniques to analyze the EqERV gene expression in different targeted areas of the horse placenta.
  • They discovered that the gene is expressed across all tested areas of the equine placenta. This expression occurs even without the formation of a syncytium or erosion of the endometrium, which are typically associated with placental ERV gene expression.
  • They also noted that the level of EqERV expression showed some variation across different placental areas. The team suggested that differences in the density, height and complexity of the chorionic villi (structures forming the microcotyledons in the placenta) could account for these variations in gene expression.

Implications and Hypotheses

  • The findings from this research suggest that the EqERV gene may be involved in the functional processing of pregnancy in equines and could influence the relationship between the fetus and the mother.
  • Further research can explore how and to what extent this particular ERV gene impacts equine reproduction and fetal development, which can provide useful insights into reproductive health and disease in these animals.

Cite This Article

APA
Stefanetti V, Pascucci L, Wilsher S, Cappelli K, Capomaccio S, Reale L, Passamonti F, Coletti M, Crociati M, Monaci M, Marenzoni ML. (2021). Differential Expression Pattern of Retroviral Envelope Gene in the Equine Placenta. Front Vet Sci, 8, 693416. https://doi.org/10.3389/fvets.2021.693416

Publication

Frontiers in veterinary science
ISSN: 2297-1769
NlmUniqueID: 101666658
Country: Switzerland
Language: English
Volume: 8
Pages: 693416
PII: 693416

Researcher Affiliations

Stefanetti, Valentina
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
Pascucci, Luisa
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
Wilsher, Sandra
  • The Paul Mellon Laboratory of Equine Reproduction, 'Brunswick', Newmarket, United Kingdom.
Cappelli, Katia
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
Capomaccio, Stefano
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
Reale, Lara
  • Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy.
Passamonti, Fabrizio
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
Coletti, Mauro
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
Crociati, Martina
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
  • Centre for Perinatal and Reproductive Medicine, University of Perugia, Perugia, Italy.
Monaci, Maurizio
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
  • Centre for Perinatal and Reproductive Medicine, University of Perugia, Perugia, Italy.
Marenzoni, Maria Luisa
  • Department of Veterinary Medicine, University of Perugia, Perugia, Italy.

Conflict of Interest Statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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