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The complexity and plasticity of cell fate determination has intrigued cell and developmental biologists for decades. Cellular differentiation is the acquisition of specialized characteristics; which is intimately associated with changes in gene expression, alterations of chromatin, and changes in nuclear architecture. Differentiating tissues exhibit a progressive restriction of cellular plasticity. However, the regenerative ability of some organisms has revealed an amazing capacity for dramatic switches in cell fate, through trans-differentiation and de-differentiation (Sanchez Alvarado and Tsonis, 2006). Furthermore, the groundbreaking work on somatic cell nuclear reprogramming and induced pluripotency has revealed that commitment to cell fate can be far more flexible than previously thought (Lensch and Mummery, 2013). In this research topic on cell fate we aimed to highlight new developments and outstanding questions in our understanding of how chromatin dynamics impact cell fate and cellular reprogramming. We include articles discussing cell fate decisions in a wide variety of contexts and model organisms. The contributions to this topic include review articles, mini-reviews, original research, and perspectives. The work described here encompasses organisms ranging from C. elegans to humans and deals with global cell fate issues of sex determination (Lau and Csankovszki), lineage choice (Chin), preventing premature differentiation (Foret et al.) cell fate and cell cycle regulation (Oyama et al.; Julian and Blais; Ma et al.; Parker), nuclear architecture (Talamas and Capelson) and how dynamic transcriptional repressors promote cell fate choices (Kok and Arnosti). We thank the authors, reviewers and editors for contributing to the stimulating discussion of the open questions in this rapidly changing field.

Since the earliest observations of cells undergoing mitosis, it has been clear that there is an intimate relationship between the cell cycle and nuclear chromatin architecture. The nuclear envelope and chromatin undergo robust assembly and disassembly during the cell cycle, and transcriptional and post-transcriptional regulation of histone biogenesis and chromatin modification is controlled in a cell cycle-dependent manner. Chromatin binding proteins and chromatin modifications in turn influence the expression of critical cell cycle regulators, the accessibility of origins for DNA replication, DNA repair, and cell fate. In this review we aim to provide an integrated discussion of how the cell cycle machinery impacts nuclear architecture and vice-versa. We highlight recent advances in understanding cell cycle-dependent histone biogenesis and histone modification deposition, how cell cycle regulators control histone modifier activities, the contribution of chromatin modifications to origin firing for DNA replication, and newly identified roles for nucleoporins in regulating cell cycle gene expression, gene expression memory and differentiation. We close with a discussion of how cell cycle status may impact chromatin to influence cell fate decisions, under normal contexts of differentiation as well as in instances of cell fate re-programming.