Year 2

The discovery of induced pluripotent stem (iPS) cells by Shinya Yamanaka in 2006 marks a major landmark in the fields of stem cell biology and regenerative medicine. iPS cells can be obtained by co‐expression of four transcription factors in differentiated cells. The reprogramming process takes 2‐3 weeks and is very inefficient with about 1 in a 1000 somatic cells giving rise to an iPS cell. In previous work, we and others had demonstrated that mouse iPS cells are highly similar to ES cells in their molecular and functional characteristics as they for example can support adult chimerism with germline
contribution. The goal of the New Faculty Award proposal is to understand the molecular mechanisms underlying transcription factor‐ induced reprogramming of differentiated cells and to define the iPS cell state.

During this funding period, our efforts have focused on all three Aims. Within Aim 1, we have addressed a range of technical strategies to improve the reprogramming process. In Aim 2, we have analyzed human and mouse iPS cells in comparison to ES cells and attempted a better definition of the iPS cell state. In Aims 3, we are currently attempting to define barriers of the reprogramming process and begin to understand the transcriptional network that leads to reprogrammed cells.