Nanoscale analysis of human G1 and metaphase chromatin in situ

Chen, J. K.; Liu, T.; Cai, S.; Ruan, W.; Ng, C. T.; Shi, J.; Surana, U.; Gan, L.

doi:10.1101/2023.07.31.551204

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bioRxiv · 10.1101/2023.07.31.551204

Nanoscale analysis of human G1 and metaphase chromatin in situ

Chen, J. K.·Liu, T.·Cai, S.·Ruan, W.·Ng, C. T.·Shi, J.·Surana, U.·Gan, L.

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Abstract

The structure of chromatin at the nucleosome level inside cells is mysterious. Here we present in situ electron cryotomography analyses of chromatin in both G1 and metaphase RPE-1 cells. G1 nucleosomes are concentrated in globular chromatin domains and metaphase nucleosomes are concentrated in the chromatids. Classification analysis reveals that canonical mononucleosomes, ordered stacked dinucleosomes, and mononucleosomes with a disordered gyre-proximal density are abundant in both cell-cycle states. Class averages that have more than two stacked nucleosomes or that have side-by-side dinucleosomes are not detected, suggesting that groups of more than two nucleosomes are heterogeneous. Large multi-megadalton structures are abundant in G1 nucleoplasm, but not found in G1 chromatin domains and metaphase chromatin. The macromolecular phenotypes studied here represent a starting point for the comparative analysis of compaction in normal and unhealthy human cells, other cell-cycle states, other organisms, and in vitro chromatin assemblies.

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Chen, J. K., Liu, T., Cai, S., Ruan, W., Ng, C. T., Shi, J., Surana, U., Gan, L.. 2023-07-31. Nanoscale analysis of human G1 and metaphase chromatin in situ. https://doi.org/10.1101/2023.07.31.551204

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