Transcription factor access is mediated by accurately positioned nucleosomes on the mouse mammary tumor virus promoter.
A fragment of the mouse mammary tumor virus (MMTV) promoter was reconstituted from pure histones into a dinucleosome with uniquely positioned octamer cores. Core boundaries for the in vitro-assembled dinucleosome corresponded to the observed in vivo phasing pattern for long terminal repeat nucleosomes A and B. Nuclear factor 1 (NF1), a constituent of the MMTV transcription initiation complex, was excluded from the assembled dinucleosome, whereas the glucocorticoid receptor was able to bind. During transcription of MMTV in vivo, displacement of nucleosome B was necessary to permit assembly of the initiation complex. These results indicate that the nucleoprotein structure of the promoter can provide differential access to sequence-specific DNA-binding proteins and that active chromatin remodeling can occur during transcription activation.
Archer
T K
TK
Hormone Action and Oncogenesis Section, National Cancer Institute, Bethesda, Maryland 20892.
Cordingley
M G
MG
Wolford
R G
RG
Hager
G L
GL
D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism / Q000648:ultrastructure; D004279:DNA, Viral / Q000235:genetics; D006657:Histones / Q000302:isolation & purification / Q000378:metabolism; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D051379:Mice; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000378:metabolism*
D002843:Chromatin; D004279:DNA, Viral; D006657:Histones; D009707:Nucleosomes; D035362:Transcription Factor TFIID; D014157:Transcription Factors