![]() Recent work has shown that a selective gene transcription program is maintained throughout mitosis ( Palozola et al. This raises the important question of how the two daughter cells retain the memory of a defined gene expression program. As cells exit mitosis and reform the nuclear envelope (NE), the transcriptional program is faithfully reactivated ( Prasanth et al. 2018), and exclusion of RNA polymerase II (Pol II) and most transcription factors (TFs) from chromatin ( Gottesfeld and Forbes 1997). ![]() This drastic reduction in transcriptional activity is associated with chromosome condensation ( Vagnarelli 2013), loss of long-range DNA interactions ( Naumova et al. Mitosis marks a dramatic transition during which cells move from a transcriptionally active to a largely repressed state in which most genes are transcriptionally inactive ( Prescott and Bender 1962). We thus provide insights into the histone modification landscape that allows faithful reestablishment of the transcriptional program and TADs during cell division. Together, our results suggest that the genome is reorganized in a sequential order, in which histone methylations occur first in prometaphase, histone acetylation, and CTCF in anaphase/telophase, transcription in cytokinesis, and long-range chromatin interactions in early G1. This increase of H3K27ac in anaphase/telophase is required for posttranscriptional activation and may play a role in the establishment of topologically associating domains (TADs). Insulators also gain H3K27ac and CCCTC-binding factor (CTCF) in anaphase/telophase. As cells exit mitosis, promoters regain H3K27ac, which correlates with transcriptional reactivation. Enhancers globally retaining mitotic H3K4me1 or locally retaining mitotic H3K27ac are associated with cell type-specific genes and their transcription factors for rapid transcriptional activation. Combined with EU-RNA-seq and Hi-C analyses, we found that during prometaphase, promoters, enhancers, and insulators retain H3K4me3 and H3K4me1, while losing H3K27ac. ![]() Here, we used ChIP-seq on synchronized cells at different stages after mitosis to generate genome-wide maps of histone modifications. Many aspects of the underlying principles that mediate transcriptional memory and reactivation in the daughter cells remain unclear. Embracing these values, we carved out a successful niche for ourselves in the creation of innovative commercial, workplace, adaptive reuse, affordable housing, medical office, and sacred spaces.During mitosis, transcription of genomic DNA is dramatically reduced, before it is reactivated during nuclear reformation in anaphase/telophase. Successful solutions that brought value to the community were realized by engaging our clients in the design process. We differentiated ourselves from the prevailing landscape of architects in this “large firm” town with a design-intensive studio that emphasized research with every project. Our work was informed through close collaborations with clients, contractors, fabricators, artists, and the community at large. As a studio of six, we collectively pursued our passion for modern architecture with every project. Founder and principal architect of Process Architecture an Orlando, Florida, architecture firm.
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