The cells were used directly without isolating total RNA in accordance with manufacturer recommendations. mESCs were lysed in the reaction buffer included in the SMARTer Ultra Low RNA Kit v3 (TaKaRa, Japan). cDNA was then synthesized using the SMARTer Ultra Low RNA Kit followed by library construction using the Nextera DNA Sample Preparation Kit (Illumina, San Diego, CA), according to the manufacturers' protocols. We performed 10 cycles of PCR for 1000 cells (~10 ng RNA) (SMARTer 1000), and 18 cycles of PCR for 100 cells (~ 1 ng RNA) (SMARTer 100).
GEO Accession
GSM3774130