Triton x 100 10

Lineage-depleted bone marrow cells were obtained by crushing and stained with the following antibodies on ice for 30 min: CD41, CD45, CD51, CD61, CD71, CD200, Ter119 and VCAM1 (Table S4). Indexed single-cells were sorted into 5μl of Smart-Seq2 lysis buffer (2μM oligo-dT30VN primer, 2mM dNTP mix (10mM each, NEB), 1:50 RNAse inhibitor (promega) and 1:125 Triton X-100 10% (Sigma-Aldrich)) and immediately snap frozen in an ethanol and dry ice bath. Plates were kept at -80 °C until processing. cDNA amplification was performed using a modified Smart-Seq2 protocol by adding, after 3 min at 72 °C, 5μl of RT mix containing 1× SMART First Strand Buffer (Clontech), 2 mM dithiothreitol (Clontech), 2 μM template switching oligo (Exiqon), 10 U μl-1 SMARTScribe (Clontech) and 10 U μl-1 RNASin plus (Promega). Transcriptome amplification was performed using 1X KAPA HiFi HS MM and 0.1μM ISPCR primer, with 21 PCR enrichment cycles. Libraries were constructed using in house produced Tn5^{54 (link)} at 1:100 dilution and sequenced on an Illumina Next-Seq 500 sequencer, with 75 cycles single end sequencing.