In vitro cell division kinetics of highly purified HSCs transduced either with control or NUP98-HOA10hd vector. (A) Time-lapse imaging of NUP98-HOXA10hd–transduced HSC divisions in a chamber. (B) E-SLAM cells were transduced with NUP98-HOXA10hd or GFP control retroviral vector and cultured under conditions given in Figure 3A. Two days after retroviral infection in the conventional culture, single transduced cells (42 of NUP98-HOXA10hd⁺ and 78 of GFP⁺) were deposited into individual chambers of microfluidic cell culture system. Time-lapse imaging and automated image analysis were used to score first, second, and third division of each single cell over 72 hours. Thus, first division refers not to actual first division in the culture but to first division that occurred in the microfluidic device, from which subsequent divisions were tracked and cell cycle kinetics measured. Each symbol shows the proportion of single viable cells initially deposited into individual chambers of microfluidic cell culture system that had divided by the time point shown.