Methylation-sensitive binding of transcription factor YY1 to an insulator sequence within the paternally expressed imprinted gene, Peg3.
The 5'-ends of two paternally expressed mouse genes, Peg3 and Usp29, are jointly associated with a CpG island that exhibits allele-specific methylation. Sequence comparison of the regions derived from human, mouse and cow revealed the presence of two evolutionarily conserved sequence motifs including one that is repeated multiple times within the first intron of Peg3 in all three mammals. DNA mobility shift and chromatin immunoprecipitation (ChIP) assays clearly demonstrated that this motif is an in vivo binding site for the Gli-type transcription factor YY1. The YY1-binding site contains one CpG dinucleotide, and methylation of this CpG site abolishes the binding activity of YY1 in vitro. The Peg3 YY1-binding sites are methylated only on the maternal chromosome in vivo, and ChIP assays confirmed that YY1 binds specifically to the paternal allele of the gene. Promoter, enhancer and insulator assays with deletion constructs of sequence surrounding the YY1-binding sites indicate that the region functions as a methylation-sensitive insulator that may influence the imprinted expression of Peg3 and neighboring genes. The current study is the first report demonstrating the involvement of YY1 in methylation-sensitive insulator activity and suggests a potential role of this highly conserved protein in mammalian genomic imprinting.
Kim
Joomyeong
J
Genomics Division, Biology and Biotechnology Research Program, L-441, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94551, USA. kim16@llnl.gov
Kollhoff
Angela
A
Bergmann
Anne
A
Stubbs
Lisa
L
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D019175:DNA Methylation; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D018392:Genomic Imprinting; D006801:Humans; D038101:Insulator Elements; D051741:Kruppel-Like Transcription Factors; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011494:Protein Kinases; D011506:Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*; D050986:YY1 Transcription Factor
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D051741:Kruppel-Like Transcription Factors; C490820:PEG3 protein, human; C097901:Peg3 protein, mouse; C490821:Peg3 protein, rat; D011506:Proteins; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human; C494699:Yy1 protein, mouse; D011494:Protein Kinases