RT Journal
A1 Do Kim, Jeong
A1 Hinz, Angela K.
A1 Bergmann, Anne
A1 Huang, Jennifer M.
A1 Ovcharenko, Ivan
A1 Stubbs, Lisa
A1 Kim, Joomyeong
T1 Identification of clustered YY1 binding sites in imprinting control regions
JF Genome Research 
JO Genome Research 
YR 2006 
FD July 01 
VO 16 
IS 7 
SP 901 
OP 911 
DO 10.1101/gr.5091406 
UL http://genome.cshlp.org/content/16/7/901.abstract 
AB Mammalian genomic imprinting is regulated by imprinting control regions (ICRs) that are usually associated with tandem arrays of transcription factor binding sites. In this study, the sequence features derived from a tandem array of YY1 binding sites of Peg3-DMR (differentially methylated region) led us to identify three additional clustered YY1 binding sites, which are also localized within the DMRs of Xist, Tsix, and Nespas. These regions have been shown to play a critical role as ICRs for the regulation of surrounding genes. These ICRs have maintained a tandem array of YY1 binding sites during mammalian evolution. The in vivo binding of YY1 to these regions is allele specific and only to the unmethylated active alleles. Promoter/enhancer assays suggest that a tandem array of YY1 binding sites function as a potential orientation-dependent enhancer. Insulator assays revealed that the enhancer-blocking activity is detected only in the YY1 binding sites of Peg3-DMR but not in the YY1 binding sites of other DMRs. Overall, our identification of three additional clustered YY1 binding sites in imprinted domains suggests a significant role for YY1 in mammalian genomic imprinting.