RT Journal
A1 Ishihara, Ko
A1 Hatano, Naoya
A1 Furuumi, Hiroyasu
A1 Kato, Reiko
A1 Iwaki, Toru
A1 Miura, Kiyonori
A1 Jinno, Yoshihiro
A1 Sasaki, Hiroyuki
T1 Comparative Genomic Sequencing Identifies Novel Tissue-Specific Enhancers and Sequence Elements for Methylation-Sensitive Factors Implicated in Igf2/H19 Imprinting
JF Genome Research 
JO Genome Research 
YR 2000 
FD May 01 
VO 10 
IS 5 
SP 664 
OP 671 
DO 10.1101/gr.10.5.664 
UL http://genome.cshlp.org/content/10/5/664.abstract 
AB A differentially methylated region (DMR) and endoderm-specific enhancers, located upstream and downstream of the mouse H19gene, respectively, are known to be essential for the reciprocal imprinting of Igf2 and H19. To explain the same imprinting patterns in non-endodermal tissues, additional enhancers have been hypothesized. We determined and compared the sequences of human and mouse H19 over 40 kb and identified 10 evolutionarily conserved downstream segments, 2 of which were coincident with the known enhancers. Reporter assays in transgenic mice showed that 5 of the other 8 segments functioned as enhancers in specific mesodermal and/or ectodermal tissues. We also identified a conserved 39-bp element that appeared repeatedly within the DMR and formed complexes with specific nuclear factors. Binding of one of the factors was inhibited when the target sequence contained methylated CpGs. These complexes may contribute to the presumed boundary function of the unmethylated DMR, which is proposed to insulate maternalIgf2 from the enhancers. Our results demonstrate that comparative genomic sequencing is highly efficient in identifying regulatory elements.[The sequence data described in this paper have been submitted to GenBank under accession nos. AF087017 and AF049091.]