WIKIMEDIA, POGREBNOJ-ALEXANDROFFA protein called syncytin, which is of viral origin but several times over evolutionary history has integrated into the genomes of mammals, supports the increase of muscle mass in male mice, according to a study published this week (September 13) in PLOS Genetics. Syncytin was already known to enable placenta formation, and its role in males may help explain why male mammals tend to be bigger and stronger than females.
“This is the first strong line of evidence that retroviral envelope proteins play an important role beyond the placenta,” Cedric Feschotte, an evolutionary biologist at the University of Utah who was not involved in the research, told Nature.
In viruses, syncytin enables membrane fusion with host cells to empty a virus’s genomic content into the cytoplasm. In mammals, the protein plays a similar role in directing cell fusion during the formation of the outer layer of the placenta. “It’s a little mind-boggling to think that cellular fusion is directed by a virus we acquired 30 million years ago,” Lars-Inge Larsson, a pathologist at the University of Copenhagen who did not participate in the study, told Nature.
When virologist Thierry Heidmann of France’s National Centre for ...
