Histone chaperone FACT represses retrotransposon MERVL and MERVL-derived cryptic promoters. Mus musculus

Endogenous retrovirus MERVL is specifically expressed in a minority of embryonic stem cells. To determine the restrain mechanism of MERVL, we knocked out Ssrp1 and analyzed the effect on the expression of transposable elements and coding genes. Ssrp1 further interacts with ubiquitin specific protease Usp7. We knocked down usp7 and analyzed the effect on the expression of MERVL. It turns out the deletion of ssrp1 or usp7 would lead to upregulation of MERVL. This study extends our understandings of the mechanism by novel factors regulates MERVL.