Rabbit Anti-Human KDM1B Polyclonal Antibody

Erasure and subsequent reinstatement of DNA methylation in the germline, especially at imprinted CpG islands (CGIs), is crucial to embryogenesis in mammals. The mechanisms underlying DNA methylation establishment remain poorly understood, but a number of post-translational modifications of histones are implicated in antagonizing or recruiting the de novo DNA methylation complex. In mouse oogenesis, DNA methylation establishment occurs on a largely unmethylated genome and in nondividing cells, making it a highly informative model for examining how histone modifications can shape the DNA methylome. Using a chromatin immunoprecipitation (ChIP) and genome-wide sequencing (ChIP-seq) protocol optimized for low cell numbers and novel techniques for isolating primary and growing oocytes, profiles were generated for histone modifications implicated in promoting or inhibiting DNA methylation. CGIs destined for DNA methylation show reduced protective H3K4 dimethylation (H3K4me2) and trimethylation (H3K4me3) in both primary and growing oocytes, while permissive H3K36me3 increases specifically at these CGIs in growing oocytes. Methylome profiling of oocytes deficient in H3K4 demethylase KDM1A or KDM1B indicated that removal of H3K4 methylation is necessary for proper methylation establishment at CGIs. This work represents the first systematic study performing ChIP-seq in oocytes and shows that histone remodeling in the mammalian oocyte helps direct de novo DNA methylation events.

Intercellular adhesion molecule1 (ICAM1) is involved in adhesion and transmigration of leukocytes across endothelium, promoting brain inflammation and leading to brain diseases. Here, we studied the mechanism that regulates ICAM expression in response to proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha). ICAM1 mRNA and protein levels in human brain microvascular endothelial cells dramatically increased after TNF-alpha treatment. TNF-alpha also upregulated histone demethylases KDM1B and KDM7A responsible for demethylation of H3K9me2, a well-known repression marker. Knockdown of KDM7A by a small interfering RNA reduced the ICAM1 protein level and leukocyte adhesion without an effect on ICAM1 mRNA expression. In contrast, a KDM1B knockdown did not affect TNF-alpha-induced ICAM1 expression. Thus, KDM7A-mediated ICAM1 protein upregulation is likely related to protein stability, not a histone-mediated epigenetic mechanism. Experiments with cycloheximide supported the role of KDM7A in ICAM1 protein stabilization. Further experiments suggest that KDM7A regulates ICAM1 protein stability via a lysosome-dependent pathway. Lysosome inhibitors increased the TNF-alpha-induced ICAM1 protein level and restored KDM7A knockdown-induced downregulation of ICAM1. In contrast, the KDM7A knockdown had no effect on proteasome-mediated ICAM1 degradation. We also found that the transcription factor EB protein level reduced in response to TNF-a but increased by the KDM7A knockdown. Immunocytochemical analysis revealed weak lysosome formation with high ICAM1 immunoreactivity after TNF-alpha treatment, but KDM7A knockdown reversed this response, resulting in strong lysosome formation with ICAM1 protein clustering in lysosomes. Taken together, our results show that KDM7A mediates TNF-alpha-induced ICAM1 protein upregulation and is mediated by induction of KDM7A, which regulates the TFEB-mediated lysosomal activity. (c) 2016 Elsevier Inc. All rights reserved.