Sel1L/Hrd1 ERAD genes are enriched in quiescent and dormant HSCs.Col1α1-H2B-GFP^+/−; Rosa26-M2-rtTA^+/− mice were labeled with doxycycline for 6 weeks and then “off label chase” for 18 weeks. H2B-GFP label retention allows purification of quiescent (GFP^high) and proliferative (GFP^low) HSCs. Levels of protein aggregates in different subpopulations were detected by PROTESTAT staining. (A) Representative FACS plots of the gating strategy. (B) Summary of protein aggregate levels, as measured by PROTESTAT, in quiescent (GFP^high) and proliferative (GFP^low) HSCs relative to all HSCs. (C) Sel1L level from microarray analysis³¹  comparing quiescent (GFP^high) and proliferative (GFP^low) HSCs. Data represent reads per kilobase of transcript per million mapped reads (RPKM); each point represents a single probe. P value determined by 2-sided Wilcoxon rank-sum test. (D) qRT-PCR of ERAD genes in quiescent (GFP^high) vs proliferating (GFP^low) HSCs purified from Col1α1-H2B-GFP^+/+; Rosa26-M2-rtTA^+/+ mice. Each point represents fold change of FACS-sorted quiescent HSCs (GFP^high) vs proliferative HSCs (GFP^low) from a single mouse. Metabolically active (TMRM^high) vs inactive (TMRM^low) HSCs in 8- to 10-week-old wild-type mice were purified based on tetramethyl rhodamine methyl ester (TMRM) staining. (E) Representative FACS plots and gating strategy for sorting. (F) Summary of levels of ERAD genes by qRT-PCR. Each point represents fold change of FACS-sorted metabolically active HSCs (TMRM^high) vs inactive (TMRM^low) HSCs from a single mouse. (G) mRNA levels of Sel1L in SLAM HSCs freshly isolated or after 24 hours’ culture in SF-03 media. Data represent mean ± SD unless stated otherwise. Two-sided Student t test was used for statistical analysis unless specified otherwise.