Genome stability in different mouse embryonic stem cells

Naïve mouse ESCs exhibit full term developmental competence thus hold great potential in regenerative medicine. Maintaining genome stability is essential for potential application of ESCs in stem cell therapy. While ESC potency fluctuate with retrovirus activity, it is unclear whether long-term cultures affect retrotransposition and genomic stability. We compared retrotransposons in naïve ESCs using various approaches. We show that feeder-serum based culture conditions and small molecule LCDM maintain appropriate expression of retrovirus activity following long-term cultures, whereas cultures under 2iLif and a2i result in aberrant upregulation of retrotransposons. This leads to high frequent retrotransposition. Moreover, naïve ESCs on feeder-serum based culture conditions and small molecule LCDM still generate complete ESC pups by TEC assay, functional test of pluripotency, following long-term cultures, despite that all culture conditions maintain high expression levels of pluripotent genes such as Oct4, Nanog, Klf4 and Sox2. Meanwhile, long telomeres are maintained in ESCs under cultures in Feeder-serum and LCDM conditions but telomeres shortened in other conditions with increasing passages. These data provide insights into retrotransposition, genomic stability and pluripotency of naïve ESCs. Overall design: We used 5 different ESC culture conditions to do RNA-seq for analysis the gene expression of pluripotent genes, Endogenous retroviruses and epigenetic regulators.