Monitoring Binding and Target-search Dynamics of Epigenetic Regulatory Factors Using Live-Cell Single-Molecule Tracking

Video S1: Example population single-molecule tracking experiment. HT-CBX2 is sparsely labeled in mES cells and tracked via stroboscopic bursts to determine fraction of stably- and transiently-bound molecules. Video S2: Example residence single-molecule tracking experiment. HT-CBX2 is sparsely labeled in mES cells and tracked via long integration times to determine the residence time of bound molecules. Video S3: Example angular distribution single-molecule tracking experiment. HT-CBX2 is labeled in mES cells using TMR to locate condensates. HT-CBX2 is also sparsely labeled by JF646 to track individual molecules to determine both the number of molecules inside and outside of condensates as well as angular distribution of molecules in relation to their condensate occupation status. Image S1 (related to Video S3): Epifluorescence of HT-CBX2 labelled with TMR before single-molecule tracking. Image S2 (related Video S3): Epifluorescence of HT-CBX2 labelled with TMR after single-molecule tracking.

视频S1：群体单分子追踪（single-molecule tracking）示例实验。HT-CBX2在小鼠胚胎干细胞（mES cells）中被稀疏标记，通过频闪脉冲（stroboscopic bursts）进行追踪，以确定稳定结合与瞬时结合分子的占比。
视频S2：停留单分子追踪（single-molecule tracking）示例实验。HT-CBX2在mES细胞中被稀疏标记，通过长积分时长进行追踪，以测定结合分子的停留时间（residence time）。
视频S3：角分布（angular distribution）单分子追踪（single-molecule tracking）示例实验。研究人员采用TMR标记HT-CBX2以定位细胞内的生物凝集体（condensates）；同时使用JF646对HT-CBX2进行稀疏标记，以追踪单个分子，进而明确凝集体内外的分子数量，以及分子相对于其凝集体占据状态的角分布。
图片S1（与视频S3相关）：单分子追踪前，经TMR标记的HT-CBX2的落射荧光（epifluorescence）图像。
图片S2（与视频S3相关）：单分子追踪后，经TMR标记的HT-CBX2的落射荧光（epifluorescence）图像。