title: Distribution of somatic H1 subtypes is non-random on active vs. inactive chromatin II: distribution in human adult fibroblasts.
abstract: For nearly twenty years researchers have observed changes in the histone H1 subtype content of tissues as an organism develops into an adult. To better understand the consequences of such changes, immunofractionation of chromatin using previously characterized antibodies specific for human H1 subtypes was employed in the analysis of a fibroblast cell strain derived from a 37-year-old individual. DNAs isolated from immunoprecipitates were probed for the existence of a variety of DNA sequences. The results presented lend further support to a previously-proposed model (Parseghian et al. [2000] Chromosome Res 8:405-424) in which transcription of a sequence is accompanied by the selective depletion of subtypes. The data also suggest that there is more total H1 on actively transcribed sequences in these cells as compared to fetal fibroblasts and that there is less difference in the subtype compositions of active genes vs. inactive sequences in this strain. Specifically, the consequences of these changes appear to correlate with the attenuation of the heat shock response in aging fibroblasts. In a broader context, these results could explain why there are reductions in transcription in cells from mature tissue that approach senescence.
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California 92697, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Parseghian
authors.forename: R L
authors.initials: RL
authors.lastname: Newcomb
authors.forename: B A
authors.initials: BA
authors.lastname: Hamkalo
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000235:genetics*; D002503:Centromere / Q000235:genetics; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D004276:DNA, Satellite / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005333:Fetus / Q000166:cytology / Q000502:physiology; D005347:Fibroblasts / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D020868:Gene Silencing; D005796:Genes; D018841:HSP90 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000235:genetics / Q000378:metabolism; D007145:Immunoglobulin kappa-Chains / Q000235:genetics / Q000378:metabolism; D051821:Lymphoid Enhancer-Binding Factor 1; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D011544:Pseudogenes; D051498:Receptor, Fibroblast Growth Factor, Type 3; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D016615:Telomere / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D002843:Chromatin; D004276:DNA, Satellite; D004268:DNA-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D006657:Histones; D007127:Immunoglobulin Constant Regions; D007145:Immunoglobulin kappa-Chains; D051821:Lymphoid Enhancer-Binding Factor 1; D009419:Nerve Tissue Proteins; D016271:Proto-Oncogene Proteins c-myc; D017468:Receptors, Fibroblast Growth Factor; D014157:Transcription Factors; C033652:postsynaptic density proteins; C496365:FGFR3 protein, human; D011505:Protein-Tyrosine Kinases; D051498:Receptor, Fibroblast Growth Factor, Type 3