Epigenetic Dysregulation Induces Translocation of Histone H3 into Cytoplasm.

In eukaryote cells, core components of chromatin, such as histones and DNA, are packaged in nucleus. Leakage of nuclear materials into cytosol will induce pathological effects. However, the underlying mechanisms remain elusive. Here, cytoplasmic localization of nuclear materials induced by chromatin dysregulation (CLIC) in mammalian cells is reported. H3K9me3 inhibition by small chemicals, HP1α knockdown, or knockout of H3K9 methylase SETDB1, induces formation of cytoplasmic puncta containing histones H3.1, H4 and cytosolic DNA, which in turn activates inflammatory genes and autophagic degradation. Autophagy deficiency rescues H3 degradation, and enhances the activation of inflammatory genes. MRE11, a subunit of MRN complex, enters cytoplasm after heterochromatin dysregulation. Deficiency of MRE11 or NBS1, but not RAD50, inhibits CLIC puncta in cytosol. MRE11 depletion represses tumor growth enhanced by HP1α deficiency, suggesting a connection between CLIC and tumorigenesis. This study reveals a novel pathway that heterochromatin dysregulation induces translocation of nuclear materials into cytoplasm, which is important for inflammatory diseases and cancer.

[Purification and analysis of Cimicifuga foetida glycoprotein ( CF- I )].

A kind of glycoprotein ( CF- I ) was extracted from Cimicifuga foetida and purified by DEAE-Cellulose ( DEAE-52) and Sepharose CL-4B. It was identified to be homogeneous glycoprotein complex by electrophoresis and fast protein liquid chromatography (FPLC). alpha-glucosidic bond was detrermined by IR. Typical absorption of polysaccharide was shown in its IR spectrum. It had no typical absorption of nucleic acid or pigment by UV scanning. Glucose, galactose, mannose and arabinose were identified in CF- I with the molar ratio of 11. 94: 2. 18: 1. 38: 1 by GC. Its average MW was estimated to be 5. 8 x 10' by gel filtration. The content of total saccharide, protein and acid polysaccharide was 78% , 14. 4% and 23% respectively. It might be composed of 1-->4 and 1-->6 linked glucopyranose by periodate oxidation and Smith degration.