Epigenetic regulation of TTF-I-mediated promoter-terminator interactions of rRNA genes.
Ribosomal RNA synthesis is the eukaryotic cell's main transcriptional activity, but little is known about the chromatin domain organization and epigenetics of actively transcribed rRNA genes. Here, we show epigenetic and spatial organization of mouse rRNA genes at the molecular level. TTF-I-binding sites subdivide the rRNA transcription unit into functional chromatin domains and sharply delimit transcription factor occupancy. H2A.Z-containing nucleosomes occupy the spacer promoter next to a newly characterized TTF-I-binding site. The spacer and the promoter proximal TTF-I-binding sites demarcate the enhancer. DNA from both the enhancer and the coding region is hypomethylated in actively transcribed repeats. 3C analysis revealed an interaction between promoter and terminator regions, which brings the beginning and end of active rRNA genes into close contact. Reporter assays show that TTF-I mediates this interaction, thereby linking topology and epigenetic regulation of the rRNA genes.
Németh
Attila
A
Department of Biochemistry III, University of Regensburg, Regensburg, Germany.
Guibert
Sylvain
S
Tiwari
Vijay Kumar
VK
Ohlsson
Rolf
R
Längst
Gernot
G
D000818:Animals; D001667:Binding, Competitive / Q000235:genetics; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D044127:Epigenesis, Genetic / Q000502:physiology*; D020459:Genes, rRNA / Q000502:physiology*; D051379:Mice; D041681:NIH 3T3 Cells; D011401:Promoter Regions, Genetic / Q000502:physiology*; D011485:Protein Binding / Q000235:genetics; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology
D004268:DNA-Binding Proteins; D014157:Transcription Factors; C504004:Ttf1 protein, mouse