Epigenetic regulation of lymphoid specific gene sets.
Coregulation of lymphoid-specific gene sets is achieved by a series of epigenetic mechanisms. Association with higher-order chromosomal structures (nuclear subcompartments repressing or favouring gene expression) and locus control regions affects recombination and transcription of clonotypic antigen receptors and expression of a series of other lymphoid-specific genes. Locus control regions can regulate DNA methylation patterns in their vicinity. They may induce tissue- and site-specific DNA demethylation and affect, thereby, accessibility to recombination-activating proteins, transcription factors, and enzymes involved in histone modifications. Both DNA methylation and the Polycomb group of proteins (PcG) function as alternative systems of epigenetic memory in lymphoid cells. Complexes of PcG proteins mark their target genes by covalent histone tail modifications and influence lymphoid development and rearrangement of IgH genes. Ectopic expression of protein noncoding microRNAs may affect the generation of B-lineage cells, too, by guiding effector complexes to sites of heterochromatin assembly. Coregulation of lymphoid and viral promoters is also possible. EBNA 2, a nuclear protein encoded by episomal Epstein-Barr virus genomes, binds to the cellular protein CBF1 (C promoter binding factor 1) and operates, thereby, a regulatory network to activate latent viral promoters and cellular promoters associated with CBF1 binding sites.
Györy
Ildikó
I
Microbiological Research Group, National Center for Epidemiology, Budapest, Hungary.
Minarovits
Janos
J
D000818:Animals; D000941:Antigens / Q000737:chemistry; D001402:B-Lymphocytes / Q000378:metabolism*; D001665:Binding Sites; D002875:Chromosomes / Q000648:ultrastructure; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000378:metabolism; D044127:Epigenesis, Genetic; D019309:Epstein-Barr Virus Nuclear Antigens / Q000378:metabolism; D005786:Gene Expression Regulation; D020868:Gene Silencing; D004854:Herpesvirus 4, Human / Q000378:metabolism; D006657:Histones / Q000737:chemistry; D006801:Humans; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D019901:Locus Control Region; D008565:Membrane Proteins / Q000378:metabolism; D035683:MicroRNAs / Q000737:chemistry / Q000235:genetics; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism; D063146:Polycomb-Group Proteins; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051880:Receptors, Notch; D011995:Recombination, Genetic; D012097:Repressor Proteins / Q000378:metabolism; D014158:Transcription, Genetic; D014764:Viral Proteins
D000941:Antigens; D004268:DNA-Binding Proteins; C402641:EBNA-2 protein, Human herpesvirus 4; D019309:Epstein-Barr Virus Nuclear Antigens; D006657:Histones; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D008565:Membrane Proteins; D035683:MicroRNAs; D009687:Nuclear Proteins; D063146:Polycomb-Group Proteins; C497570:RBPJ protein, human; D051880:Receptors, Notch; D012097:Repressor Proteins; D014764:Viral Proteins