Structural analysis of human KDM5B guides histone demethylase inhibitor development.

Members of the KDM5 (also known as JARID1) family are 2-oxoglutarate- and Fe(2+)-dependent oxygenases that act as histone H3K4 demethylases, thereby regulating cell proliferation and stem cell self-renewal and differentiation. Here we report crystal structures of the catalytic core of the human KDM5B enzyme in complex with three inhibitor chemotypes. These scaffolds exploit several aspects of the KDM5 active site, and their selectivity profiles reflect their hybrid features with respect to the KDM4 and KDM6 families.

v-Jun overrides the mitogen dependence of S-phase entry by deregulating retinoblastoma protein phosphorylation and E2F-pocket protein interactions as a consequence of enhanced cyclin E-cdk2 catalytic activity.

v-Jun accelerates G(1) progression and shares the capacity of the Myc, E2F, and E1A oncoproteins to sustain S-phase entry in the absence of mitogens; however, how it does so is unknown. To gain insight into the mechanism, we investigated how v-Jun affects mitogen-dependent processes which control the G(1)/S transition. We show that v-Jun enables cells to express cyclin A and cyclin A-cdk2 kinase activity in the absence of growth factors and that deregulation of cdk2 is required for S-phase entry.

Human papillomavirus type 16 E7 regulates E2F and contributes to mitogenic signalling.

We have produced human papillomavirus type 16 E7 protein in a bacterial expression system and examined the mitogenic activity of this protein in Swiss 3T3 cells after scrape loading. The ability of E7 to induce cellular DNA synthesis in quiescent mouse fibroblasts is strongly enhanced by the presence of a single growth factor such as insulin. Although only weakly mitogenic, introduction of E7 alone resulted in the rapid induction of the transcriptionally active form of E2F, which was not enhanced further by the addition of insulin.

Nuclear accumulation of a heat-shock 70-like protein during herpes simplex virus replication.

A monoclonal antibody defines an antigen, p68, related to hsp70, which is located in nuclei of uninfected exponential cells. Nuclear p68 is released by DNase but not RNase treatment suggesting an association with DNA. Lytic productive infection of confluent quiescent BHK 21 cells with herpes simplex virus type-2 causes p68 to accumulate in nuclei.

A cultured human oligodendroglioma cell line and herpes simplex virus-infected cells share antigenic determinants.

Cell cultures derived from 60 different human brain tumors were screened for the presence of HSV infected cell antigens by indirect immunofluorescence using a polyclonal rabbit antiserum reacting with herpes simplex virus (HSV), 3 monoclonal antibodies recognising different HSV-specified proteins, and one monoclonal antibody T181 reacting with a DNA binding protein present in HSV-infected cells. Only one tumor (IN/157), derived from an oligodendroglioma, stained with the polyclonal antiserum. T181 but none of the other monoclonal antibodies used also specifically reacted with IN/157 cells.

A filamentous distribution for the herpes simplex virus type 2-encoded major DNA-binding protein.

Monoclonal antibodies reacting with the herpes simplex virus (HSV)-encoded major DNA-binding protein defined an intracellular filamentous network. This network was associated predominantly with the infected cell nucleus and occurred in cells infected with HSV type 2. It did not co-distribute with microfilaments, microtubules or intermediate filaments, and DNA synthesis was required for its formation.

Cultured human neural cells accumulate a heat-shock protein during acute herpes simplex virus infection.

Herpes simplex virus-1 (HSV-1) infection of cultured human neural cells causes the accumulation of a host cell-encoded nuclear protein identified as a 57,000 mol.wt. stress protein by monoclonal antibody TI56.

Chromatin proteins share antigenic determinants with neurofilaments.

Antigenic determinants common to distinct proteins may be unambiguously identified by the use of monoclonal antibodies. Some monoclonal antibodies to mammalian neurofilaments have recently been shown to cross-react with the neurofibrillary tangles found at high density in the brains of senile dements with Alzheimers disease (SDAT). Here, we show that these antibodies also cross-react with chromatin proteins, including the linker histones H1 and H1(0).

A major heat-shock protein defined by a monoclonal antibody.

A monoclonal antibody reacts with a polypeptide of 68 000 mol. wt. (p68) that accumulates to high levels during heat shock.

Herpes simplex virus infection causes the accumulation of a heat-shock protein.

A monoclonal antibody, produced from mice immunized with a herpes simplex virus (HSV)-infected cell extract, reacts with a molecule which is present in uninfected cells and which accumulates in large amounts during HSV 2 infection. In uninfected cells this molecule is growth regulated, in that exponentially growing cells have intense nuclear immunofluorescence, whereas confluent quiescent cells have little. It has a mol.