Affiliation:
1. UMR 8122, Unité des Rétrovirus Endogènes et Éléments Rétroïdes des Eucaryotes Supérieurs, CNRS, Institut Gustave Roussy, 94805 Villejuif, France
2. Université Paris-Sud XI, 91405 Orsay, France
Abstract
The development of the emerging field of ‘paleovirology’ allows biologists to reconstruct the evolutionary history of fossil endogenous retroviral sequences integrated within the genome of living organisms and has led to the retrieval of conserved, ancient retroviral genes ‘exapted’ by ancestral hosts to fulfil essential physiological roles,
syncytin
genes being undoubtedly among the most remarkable examples of such a phenomenon. Indeed, s
yncytins
are ‘new’ genes encoding proteins derived from the envelope protein of endogenous retroviral elements that have been captured and domesticated on multiple occasions and independently in diverse mammalian species, through a process of convergent evolution. Knockout of
syncytin
genes in mice provided evidence for their absolute requirement for placenta development and embryo survival, via formation by cell–cell fusion of syncytial cell layers at the fetal–maternal interface. These genes of exogenous origin, acquired ‘by chance’ and yet still ‘necessary’ to carry out a basic function in placental mammals, may have been pivotal in the emergence of mammalian ancestors with a placenta from egg-laying animals via the capture of a founding retroviral
env
gene, subsequently replaced in the diverse mammalian lineages by new
env-
derived
syncytin
genes, each providing its host with a positive selective advantage.
Subject
General Agricultural and Biological Sciences,General Biochemistry, Genetics and Molecular Biology
Cited by
301 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献