Chromatin structure at the 3'-boundary of the human beta-globin locus control region hypersensitive site-2.
Chromatin structure was examined at the 3'-boundary region of the human beta-globin locus control region hypersensitive site-2 (LCR HS-2) using several footprinting agents. Erythroid K562 cells (possessing HS-2) were damaged by the footprinting agents: hedamycin, bleomycin and four nitrogen mustard analogues. Purified DNA and non-erythroid HeLa cells (lacking HS-2) were also damaged as controls for comparison with K562 cells. The comparison between intact cells and purified DNA showed several protected regions in K562 cells. A large erythroid-specific protected region of 135 bp was found at the boundary of HS-2. The length of this protected region (135 bp) was close to that of DNA contained in a nucleosome core (146 bp). Another two protected regions were found upstream of the protected region. A 16-bp erythroid-specific footprint co-localised with a GATA-1 motif-this indicated that the GATA-1 protein could be involved in positioning the nucleosome. Further upstream, a 100-bp footprint coincided with an AT-rich region. Thus our footprinting results suggest that the 3'-boundary of LCR HS-2 is flanked by a positioned nucleosome and that an erythroid-specific protein binds to the sequence adjacent to the nucleosome and acts to position the nucleosome at the boundary of the hypersensitive site.
Kim
A R
AR
School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney, NSW 2052, Australia.
Murray
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D000477:Alkylating Agents / Q000494:pharmacology; D020816:Amino Acid Motifs; D000880:Anthraquinones / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001665:Binding Sites; D001761:Bleomycin / Q000494:pharmacology; D002843:Chromatin / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000032:analysis / Q000378:metabolism; D005914:Globins / Q000737:chemistry* / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D007364:Intercalating Agents / Q000494:pharmacology; D020014:K562 Cells; D008466:Mechlorethamine / Q000494:pharmacology; D008957:Models, Genetic; D005810:Multigene Family; D011485:Protein Binding; D014176:Protein Biosynthesis; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
D000477:Alkylating Agents; D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D002843:Chromatin; D007364:Intercalating Agents; C001328:hedamycin; D001761:Bleomycin; D008466:Mechlorethamine; D005914:Globins; D004247:DNA