Genomic organization and promoter analysis of the Dnmt3b gene.
The Dnmt3b gene encodes a de novo DNA methyltransferase that is essential for normal mouse development. It is highly expressed in early embryos and embryonic stem (ES) cells but downregulated in most adult somatic tissues. To gain insight into the regulation of Dnmt3b, we have isolated a mouse genomic bacterial artificial chromosome clone that contains the Dnmt3b gene. Complete sequence analysis of the clone demonstrated that Dnmt3b consists of at least 24 exons and spans 38 kilobases. S1 nuclease analysis identified two adjacent transcriptional start sites located downstream of a unique TATA-like element in a CpG island. There was an unknown gene which we named mU(3) 17 kb upstream of the Dnmt3b locus, and it was transcribed ubiquitously and in the opposite direction of Dnmt3b. Transfection analysis revealed that the minimal promoter region containing an Sp1 site was active even in somatic cells, and that there were several repressor elements within 7.9 kb upstream of Dnmt3b downregulated this gene specifically in somatic cells but not in ES cells. These findings provide a basis for future detailed studies of the mechanisms controlling Dnmt3b expression.
Ishida
Chisaki
C
Division of Gene Therapy Science, Osaka University School of Medicine, 2-2 Yamada-oka, Suita, 565-0870, Osaka, Japan.
Ura
Kiyoe
K
Hirao
Akiko
A
Sasaki
Hiroyuki
H
Toyoda
Atsushi
A
Sakaki
Yoshiyuki
Y
Niwa
Hitoshi
H
Li
En
E
Kaneda
Yasufumi
Y
D016475:3T3 Cells; D024506:5' Flanking Region / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics*; D004622:Embryo, Mammalian / Q000201:enzymology / Q000378:metabolism; D005091:Exons; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D005796:Genes / Q000235:genetics; D007438:Introns; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D024363:Transcription Initiation Site; D000097584:DNA Methyltransferase 3B
D004247:DNA; D004248:DNA (Cytosine-5-)-Methyltransferases; D008156:Luciferases; D011993:Recombinant Fusion Proteins; D000097584:DNA Methyltransferase 3B