The authors regret that an error was made in citing Reference#57. The correct citation is "Lavial F, Bessonnard S, Ohnishi Y, Tsumura A, Chandrashekran A, Fenwick MA, Tomaz RA, Hosokawa H, Nakayama T, Chambers I, Hiiragi T, Chazaud C, Azuara V. Bmi1 facilitates primitive endoderm formation by stabilizing Gata6 during early mouse development. Genes Dev.2012 Jul 1; 26 (13): 1445e1458". In the text on p.229 right column, Line14, the first author's name should be Lavial. The authors would like to apologize for any inconvenience and confusion caused by the error.