Identifying Human Naïve Pluripotent Stem Cells - Evaluating State-Specific Reporter Lines and Cell-Surface Markers.

Recent reports that human pluripotent stem cells can be captured in a spectrum of states with variable properties has prompted a re-evaluation of how pluripotency is acquired and stabilised. The latest additions to the stem cell hierarchy open up opportunities for understanding human development, reprogramming, and cell state transitions more generally. Many of the new cell lines have been collectively termed 'naïve' human pluripotent stem cells to distinguish them from the conventional 'primed' cells. Here, several transcriptional and epigenetic hallmarks of human pluripotent states in the recently described cell lines are reviewed and evaluated. Methods to derive and identify human naïve pluripotent stem cells are also discussed, with a focus on the uses and future developments of state-specific reporter cell lines and cell-surface proteins. Finally, opportunities and uncertainties in naïve stem cell biology are highlighted, and the current limitations of human naïve pluripotent stem cells considered, particularly in the context of differentiation.Our research is funded by the BBSRC (BB/P013406/1, BB/M022285/1) and MRC (MR/J003808/1)

Single-molecule observation of DNA charge transfer

DNA charge transfer highly depends on the electronic interaction between base pairs and reflects the difference in the base composition and sequence. For the purpose of investigating the charge transfer process of individual DNA molecules and the optical readout of DNA information at the single-molecule level, we performed single-molecule observation of the DNA charge transfer process by using single-molecule fluorescence spectroscopy. The DNA charge transfer process, leading to the oxidation of the fluorescent dye, was explored by monitoring the on–off signal of the dye after the charge injection by the excitation of a photosensitizer. The photobleaching efficiency of the dyes by the DNA charge transfer specifically depended on the base sequence and mismatch base pair, demonstrating the discrimination of the individual DNA information. Based on this approach, the optical readout of a single-base mismatch contained in a target DNA was performed at the single-molecule level