library_construction_protocol: Femurs and tibias from Tnfsf11tTA/+; LC1; Rosa26LSL-tdTomato mice were isolated from both limbs, and bone marrow was flushed out with PBS. The remaining bones were minced using scissors and forceps, then incubated in 5 mM EDTA in PBS at room temperature for 1 hour. Dissociated cells were collected every 30 minutes and pooled with the bone marrow cells isolated from the same mouse. Cells were collected by centrifugation and treated with Red Blood Cell Lysis Buffer, followed by incubation in DMEM containing 1 mg/mL Collagenase P, 0.025 mg/mL Liberase TH and 0.1 mg/mL DNase I at 37ºC with gentle shaking for 1 hour. Dissociated cells were collected every 20 minutes and passed through a 100 μm nylon mesh. The cells were then collected by centrifugation, resuspended in 2% FBS/2 mM EDTA/PBS. The isolated cells were stained with antibodies against Ter119 and CD45.2. Fixable Viability Dye (eBioscience) was used to stain dead cells. Live CD45.2-Ter119-tdTomato+ cells were sorted for single cell 3' gene expression library construction. Library construction was performed according to the manufacter's instructions (single cell 3' v3.1 protocol, 10x Genomics) with slight modification.  Cells up to 10,000 were directly sorted into the master mix and loaded together with partitioning oil and gel beads into the chip to generate the gel bead-in-emulsion (GEM).