Navigation Links
Researchers discover that sheep need retroviruses for reproduction

A team of scientists from Texas A&M University and The University of Glasgow Veterinary School in Scotland has discovered that naturally occurring endogenous retroviruses are required for pregnancy in sheep.

In particular, a class of endogenous retroviruses, known as endogenous retroviruses related to Jaagsiekte sheep retrovirus or enJSRVs, are critical during the early phase of pregnancy when the placenta begins to develop.

Retroviruses, such as human immunodeficiency virus or HIV, are one class of viruses. They are best known for their ability to cause diseases, said Dr. Thomas Spencer, a reproductive biologist with the Texas Agricultural Experiment Station and Texas A&M University.

Findings published Sept. 11 in the Proceedings of the National Academy of Sciences demonstrate enJSRVs are essential for the development of the placenta in sheep.

Retroviruses are unique for their ability to permanently insert their genetic material into the DNA of host cells, he said. During evolution of mammals, some retroviruses infected the germline (cells of the ovary and testis that have genetic material that are passed to their offspring) of the host, which is then inherited by their children. These retroviruses, known as endogenous retroviruses, are present in the genome of all mammals, including humans. Consequently, endogenous retroviruses can be considered remnants of ancient retroviral infections, Spencer said.

Many scientists believed these endogenous retroviruses were junk DNA, he said.

"Indeed, these endogenous retroviruses are usually harmless and generally contain mutations that prevent them from producing infectious retroviruses," he said.

However, several endogenous retroviruses appear to provide protection from infection and are involved in reproduction. For instance, the exogenous Jaagsiekte Sheep Retrovirus or JSRV causes lung tumors in sheep and led to the death of Dolly, the world's firs t mammal cloned from an adult cell. The idea that endogenous retroviruses are important for reproduction in mammals has been around for about 30 years, Spencer said. Studies in cultured cells have shown that a protein of a human endogenous retrovirus might have a role in development of the human placenta.

The team blocked expression of the envelope of the enJSRVs using morpholino antisense oligonucleotides, which inhibit translation of specific messenger RNA. When production of the envelope protein was blocked in the early placenta, the growth of the placenta was reduced and a certain cell type, termed giant binucleate cells, did not develop.

The result was that embryos could not implant and the sheep miscarried, Spencer said.

Miscarriage is a serious medical problem for all mammals, including humans.

"Our research supports the idea that endogenous retroviruses shaped the evolution of the placenta in mammals and then became indispensable for pregnancy, and thus may be why they are expressed in the placenta of many mammals," he said.

"The enJSRVs arose from ancient infections of small ruminants during their evolution," said. Dr. Massimo Palmarini, a virologist at The University of Glasgow Veterinary School. "This infection was beneficial to the host and was then positively selected for during evolution. In other words, animals with enJSRVs were better equipped than those without. Therefore, enJSRVs became a permanent part of the sheep genome and, in these days, sheep can't do without them."

The research team is trying to determine exactly how enJSRVs function in development of the sheep placenta. Their results should have implications for both human health and animal production.
'"/>

Source:Texas A&M University - Agricultural Communications


Related biology news :

1. Researchers discover way to make cells in the eye sensitive to light
2. Researchers find how protein allows insects to detect and respond to pheromones
3. Researchers Uncover Key Step In Manufacture of Memory Protein
4. Researchers reveal the infectious impact of salmon farms on wild salmon
5. Researchers identify target for cancer drugs
6. Researchers discover molecule that causes secondary stroke
7. Researchers find missing genes of ancient organism
8. Researchers trace evolution to relatively simple genetic changes
9. Researchers add new tool to tumor-treatment arsenal
10. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
11. VCU Researchers Identify Networks Of Genes Responding To Alcohol In The Brain

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:2/14/2017)... 2017  Wake Forest Baptist Medical Center today announced Julie ... executive officer (CEO). Freischlag joins the medical center on ... , M.D., who last year announced that he would ... after leading it since 2008.   As ... Forest Baptist,s academic health system, which includes Wake Forest ...
(Date:2/9/2017)... 9, 2017 The biomass boiler market report ... biomass boiler market globally in terms of revenue (US$ ... The market for biomass boilers has been segmented on ... and country/region. The market based on feedstock type, has ... biogas & energy crops, urban residues, and others. On ...
(Date:2/8/2017)... 2017 The biometrics market has reached ... of organizations, desires to better authenticate or identify ... and challenge questions), biometrics is quickly working its ... market is driven by use cases, though there ... enterprise uses cases, with consumer-facing use cases encompassing ...
Breaking Biology News(10 mins):
(Date:2/22/2017)... ... February 22, 2017 , ... Park Systems , ... AFM Luncheon for all SPIE attendees and Park customers on Feb. ... block from the San Jose Convention Center. The luncheon will feature a talk ...
(Date:2/22/2017)... Fort Washington, PA (PRWEB) , ... ... ... The Omnia-Prova Education Collaborative (TOPEC), the leading medical education provider of ... Accreditation with Commendation by the Accreditation Council for Continuing Medical Education (ACCME). ...
(Date:2/22/2017)... ... , ... LabRoots , the leading provider of educational and interactive virtual ... announce the launch of a new scholarship for young scientists seeking a degree in ... is open to all high school seniors, 17 years or older; as well as ...
(Date:2/22/2017)... 2017 Aethlon Medical, Inc. (Nasdaq: ... that validated the ability of the Aethlon Hemopurifier® to ... mortality in immune-suppressed sepsis patients and also contribute to ... objective of the study was to validate the ... (EBV) and Herpes Simplex virus 1 (HSV1) by the ...
Breaking Biology Technology: