Fig. 1
Effect of immunostaining and FACS on the integrity of RNA. a Flow chart of the staining and sorting procedures indicating the critical steps during the FACS-mediated isolation of the subpopulations SP1–4 and the steps at which RNA integrity was analyzed. Flash-freeze indicates samples flash frozen in liquid nitrogen and stored at −80 °C after the sorting. b Qualitative integrity of total RNA from the discrete steps during the immunostaining and sorting procedure. The quantitative data are presented as mean ± SD (n = 2–4). * denotes a significant (p < 0.05) lower RIN when compared to RIN directly after fixation and permeabilization with 70% ethanol, † denotes a significant lower RIN by pairwise comparison. ABCB5 = ATP-binding cassette sub-family B member 5; CH2O = formaldehyde; C2H5OH = ethanol; CK3 = cytokeratin 3; p63 = transformation-related protein 63; LN2 = liquid nitrogen; RIN = RNA integrity number; FACS = fluorescence-activated cell sorting