The transcriptome of acute dehydration in myeloid leukemic cells.

Human myeloid leukemia cells (HL-60/S4) exposed to hyperosmotic stress with sucrose undergo dehydration and cell shrinkage. Interphase chromatin and mitotic chromosomes congeal, exhibiting altered phase separation (demixing) of chromatin proteins. To investigate changes in the transcriptome, we exposed HL-60/S4 cells to hyperosmotic sucrose stress (~600 milliOsmolar) for 30 and 60 minutes.

50th Anniversary of the Nucleosome Discovery: a Brief Essay.

50th Anniversary of the Nucleosome Discovery.

Interphase epichromatin: last refuge for the 30-nm chromatin fiber?

"Interphase epichromatin" describes the surface of chromatin located adjacent to the interphase nuclear envelope. It was discovered in 2011 using a bivalent anti-nucleosome antibody (mAb PL2-6), now known to be directed against the nucleosome acidic patch. The molecular structure of interphase epichromatin is unknown, but is thought to be heterochromatic with a high density of "exposed" acidic patches.

DNA Replication: An in vivo Space-Time Continuum in the Ciliate Replication Band.

The replication band in the macronucleus of ciliated protozoa has fascinated microscopists since the 19 Century. It migrates through the nucleus, corresponding to a region of DNA replication and nascent chromatin assembly. A new study shows that calcium and actin filaments may participate in the formation and migration of the replication band.

Linker histone epitopes are hidden by in situ higher-order chromatin structure.

Background: Histone H1 is the most mobile histone in the cell nucleus. Defining the positions of H1 on chromatin in situ, therefore, represents a challenge. Immunoprecipitation of formaldehyde-fixed and sonicated chromatin, followed by DNA sequencing (xChIP-seq), is traditionally the method for mapping histones onto DNA elements.