Anti-RNF2 (aa 156-204) polyclonal antibody

BACKGROUND: Valproic acid (VPA) is widely used to treat epilepsy and bipolar disorder and is also a potent teratogen, but its teratogenic mechanisms are unknown. We have attempted to describe a fundamental role of the Polycomb group (Pc-G) in VPA-induced transformations of the axial skeleton. METHODS: Pregnant NMRI mice were given a single subcutaneous injection of vehicle or VPA (800 mg/kg) on gestation day (GD) 8. The expression of genes encoding Polycomb and trithorax groups was measured by quantitative real-time RT-PCR using total RNA isolated from the embryos exposed to vehicle or VPA for 1, 3, and 6 hr. In addition, the use of two less teratogenic antiepileptic chemicals valpromide (VPD) and valnoctamide (VCD) provide reliable evidence to support the relationship between VPA teratogenicity and the Polycomb group. RESULTS: At a teratogenic level, VPA inhibits the expression of the Polycomb group genes, including Eed, Ezh2, Zfp144, Bmi1, Cbx2, Rnf2, and YY1 in the mouse embryos. In contrast, neither VPD nor VCD have significant effects on the expression of those genes affected by VPA. The trithorax group (trx-G) gene MLL, which is known to be required to maintain homeobox gene expression such as the Polycomb gene, is not affected by a teratogenic dose of VPA. CONCLUSIONS: We propose that, during embryonic development, VPA may affect the gene silencing pathway mediated by the Polycomb group complex. The epigenetic mechanism of VPA teratogenicity on anteroposterior patterning is suspected. (C) 2004 Wiley-Liss, Inc.

Objectives: Persistent HIV-1 infections are characterized by a long silent infection period in resting CD4+ T cells, which allows them to escape the host immune response. Several HIV-1 latency mechanisms have been reported, but the molecular mechanism underlying polycomb repressor complex (PRC)-mediated HIV-1 latency remains poorly understood. Methods: Expression of PRC proteins in latent cells was measured by Western blot. Knockdowns of PRC genes were conducted by the specific siRNA and methylations at H3K27 on the proviral LTR were investigated by ChIP assay. Results: PRC proteins (EED, BMI-1, and RNF2) were dramatically downregulated in latent cells after PMA treatment. The downregulation of PRC proteins was followed by a decrease in the methylation of H3K27 and ubiquitination of H2AK119 in the PMA-treated latent cells. siRNA knockdowns of EED and BMI-1 also enhanced HIV-1 reactivation significantly in latently infected cells. By contrast, proteasomal inhibitor MG132 successfully abrogated the PMA-induced downregulation of PRCs. In particular, di-/tri-methylations of histone-3 in the proviral LTR was absent from latent cells after PMA treatment. Conclusions: This study shows that PRC is strongly related to the control of HIV-1 latency and that PRC-breaking agents may be helpful for purging HIV-1 from latent reservoirs. (C) 2014 S. Karger AG, Basel