2.5. Lentivirus Preparation and Infection

Lentivirus production was described previously [28]. Assistant plasmids PAX2 and VSVG were cotransfected with pCDH-CMV-Eif2s3y-EF1-puro or CD513B-U6-shEif2s3y in HEK293T cells. The oeEif2s3y or shEif2s3y lentivirus was collected 48 hours later after substituted. The primary SSCs were infected with lentivirus oeEif2s3y or shEif2s3y when the density reached 80% complementing with polybrene (Sigma-Aldrich by Merck) to increase transfection efficiency. The infected SSCs were then cultured with a medium containing 500 ng/mL puromycin (Sigma-Aldrich by Merck) for 1 week in order to increase the proportion of positive cells.