Abstract
Cell Differentiation Compacted chromatin regions, marked by trimethylation of histone H3 at position lysine 9 (H3K9me3), occur at highly repeated DNA sequences, helping to suppress recombination and gene expression. Because pluripotent cells contain low levels of H3K9me3 heterochromatin relative to differentiated cells, it has been thought that an increase in such heterochromatin helps to define cell differentiation. Nicetto et al. used two independent methods to examine compacted heterochromatic domains and found that H3K9me3 compaction increased at protein-coding genes during early mouse organogenesis. During differentiation, these domains open up to allow cell-specific expression. Loss of heterochromatin by genetic inactivation of the H3K9me3 methyltransferases caused ectopic expression of cell-inappropriate genes and tissue pathology. Science , this issue p. [294][1] [1]: /lookup/doi/10.1126/science.aau0583
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
