ERVWE1

HERV-W_7q21.2 provirus ancestral Env polyprotein also known as syncytin or enverin, is a protein encoded by an endogenous viral element. In humans, the syncytin gene is called ERVWE1.

Function

Syncytins are 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, analogous to the incorporation of certain bacterial species into animal cells during the course of evolution that eventually developed into mitochondria. Gene knockout of syncytin genes in mice provides evidence for their absolute requirement for placenta development and embryo survival.

The human ERVWE1 locus is derived from a human endogenous retrovirus-W (HERV-W) provirus located on chromosome 7. This provirus has inactivating mutations in the gag and pol genes, but the envelope glycoprotein gene has been selectively preserved. The product of this gene, syncytin, is expressed in the placental syncytiotrophoblast and is involved in fusion of the cytotrophoblast cells to form the syncytial layer of the placenta. The protein has the characteristics of a typical retroviral envelope protein, including a furin cleavage site that separates the surface (SU) and transmembrane (TM) proteins which form a heterodimer.

Clinical significance

Mutations in the ERVWE1 gene have been associated with various neurological conditions such as multiple sclerosis, autism, bipolar disorder, and schizophrenia. For this reason, the HERV-W endogenous virus encoded by this gene has sometimes been referred to as the "insanity virus." There is now mounting evidence that certain triggers like infection or inflammation can activate this normally "dormant" virus in the human brain.

External links

• ERVWE1 on the Atlas of Genetics and Oncology