Competition between linker histones and HMG1 for binding to four-way junction DNA: implications for transcription.
Both lysine-rich histones and high mobility group proteins 1 and 2 bind to linker DNA in chromatin. While the members of the histone H1 class are considered general repressors of transcription, HMG1/2 are viewed as activators. Using stable four-way junction DNA as a model for cross-overs of linker DNA at the entry and exit to nucleosomes, we show that HMG1 can compete efficiently with H1 for binding to four-way junctions. In contrast, the erythrocyte-specific histone H5 seems to be refractory to displacement by HMG1. The results suggest that replacement of histone H1 by HMG1 may be part of the transcriptional activation by HMG1.
Varga-Weisz
P
P
Department of Biochemistry and Biophysics, Oregon State University, Corvallis 97331-7305.
van Holde
K
K
Zlatanova
J
J
D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002645:Chickens; D004247:DNA / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*
D006609:High Mobility Group Proteins; D006657:Histones; D009838:Oligodeoxyribonucleotides; D004247:DNA; D008274:Magnesium