Components of the human SWI/SNF complex are enriched in active chromatin and are associated with the nuclear matrix.
Biochemical and genetic evidence suggest that the SWI/SNF complex is involved in the remodeling of chromatin during gene activation. We have used antibodies specific against three human subunits of this complex to study its subnuclear localization, as well as its potential association with active chromatin and the nuclear skeleton. Immunofluorescence studies revealed a punctate nuclear labeling pattern that was excluded from the nucleoli and from regions of condensed chromatin. Dual labeling failed to reveal significant colocalization of BRG1 or hBRM proteins with RNA polymerase II or with nuclear speckles involved in splicing. Chromatin fractionation experiments showed that both soluble and insoluble active chromatin are enriched in the hSWI/SNF proteins as compared with bulk chromatin. hSWI/SNF proteins were also found to be associated with the nuclear matrix or nuclear scaffold, suggesting that a fraction of the hSWI/SNF complex could be involved in the chromatin organization properties associated with matrix attachment regions.
Reyes
J C
JC
Unité des Virus Oncogènes, UA1644 du Centre National de la Recherche Scientifique, Département des Biotechnologies, Institut Pasteur, Paris, France.
Muchardt
C
C
Yaniv
M
M
D000255:Adenosine Triphosphate / Q000494:pharmacology; D002843:Chromatin / Q000737:chemistry*; D002868:Chromosomal Proteins, Non-Histone; D004265:DNA Helicases; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D015530:Nuclear Matrix / Q000737:chemistry* / Q000378:metabolism; D009687:Nuclear Proteins / Q000032:analysis* / Q000378:metabolism; D047428:Protein Kinase Inhibitors; D000071796:SMARCB1 Protein; D014157:Transcription Factors / Q000032:analysis* / Q000378:metabolism
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; C084011:SMARCA2 protein, human; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors; D000255:Adenosine Triphosphate; C084108:SMARCA4 protein, human; D004265:DNA Helicases