DNA methyltransferase 1 and 3B activate BAG-1 expression via recruitment of CTCFL/BORIS and modulation of promoter histone methylation.
In a previous genomic analysis, using somatic methyltransferase (DNMT) knockout cells, we showed that hypomethylation decreased the expression of as many genes as were observed to increase, suggesting a previously unknown mechanism for epigenetic regulation. To address this idea, the expression of the BAG family genes was used as a model. These genes were used because their expression was decreased in DNMT1(-/-), DNMT3B(-/-), and double knockout cells and increased in DNMT1-overexpressing and DNMT3B-overexpressing cells. Chromatin immunoprecipitation analysis of the BAG-1 promoter in DNMT1-overexpressing or DNMT3B-overexpressing cells showed a permissive dimethyl-H3-K4/dimethyl-H3-K9 chromatin status associated with DNA-binding of CTCFL/BORIS, as well as increased BAG-1 expression. In contrast, a nonpermissive dimethyl-H3-K4/dimethyl-H3-K9 chromatin status was associated with CTCF DNA-binding and decreased BAG-1 expression in the single and double DNMT knockout cells. BORIS short hairpin RNA knockdown decreased both promoter DNA-binding, as well as BAG-1 expression, and changed the dimethyl-H3-K4/dimethyl-H3-K9 ratio to that characteristic of a nonpermissive chromatin state. These results suggest that DNMT1 and DNMT3B regulate BAG-1 expression via insulator protein DNA-binding and chromatin dynamics by regulating histone dimethylation.
Sun
Lunching
L
Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Huang
Lei
L
Nguyen
Phuongmai
P
Bisht
Kheem S
KS
Bar-Sela
Gil
G
Ho
Allen S
AS
Bradbury
C Matthew
CM
Yu
Wenqiang
W
Cui
Hengmi
H
Lee
Sunmin
S
Trepel
Jane B
JB
Feinberg
Andrew P
AP
Gius
David
D
D045744:Cell Line, Tumor; D002843:Chromatin; D003110:Colonic Neoplasms / Q000201:enzymology / Q000235:genetics; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D017930:Genes, Reporter; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011496:Protein Methyltransferases; D012334:RNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection; D000097584:DNA Methyltransferase 3B
D002843:Chromatin; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D017931:DNA Primers; D004268:DNA-Binding Proteins; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; D011496:Protein Methyltransferases; D012334:RNA, Neoplasm; D014157:Transcription Factors; D000097584:DNA Methyltransferase 3B; C091732:BCL2-associated athanogene 1 protein; C456540:CTCFL protein, human; C000619380:DNMT1 protein, human