Mouse ES cells express endogenous shRNAs, siRNAs, and other Microprocessor-independent, Dicer-dependent small RNAs

Babiarz JE, Ruby JG, Wang Y, Bartel DP, Blelloch R.
Genes Dev. 2008 Oct 15;22(20):2773-85. doi: 10.1101/gad.1705308.