Identification of DNA regions and a set of transcriptional regulatory factors involved in transcriptional regulation of several human liver-enriched transcription factor genes.
Mammalian tissue- and/or time-specific transcription is primarily regulated in a combinatorial fashion through interactions between a specific set of transcriptional regulatory factors (TRFs) and their cognate cis-regulatory elements located in the regulatory regions. In exploring the DNA regions and TRFs involved in combinatorial transcriptional regulation, we noted that individual knockdown of a set of human liver-enriched TRFs such as HNF1A, HNF3A, HNF3B, HNF3G and HNF4A resulted in perturbation of the expression of several single TRF genes, such as HNF1A, HNF3G and CEBPA genes. We thus searched the potential binding sites for these five TRFs in the highly conserved genomic regions around these three TRF genes and found several putative combinatorial regulatory regions. Chromatin immunoprecipitation analysis revealed that almost all of the putative regulatory DNA regions were bound by the TRFs as well as two coactivators (CBP and p300). The strong transcription-enhancing activity of the putative combinatorial regulatory region located downstream of the CEBPA gene was confirmed. EMSA demonstrated specific bindings of these HNFs to the target DNA region. Finally, co-transfection reporter assays with various combinations of expression vectors for these HNF genes demonstrated the transcriptional activation of the CEBPA gene in a combinatorial manner by these TRFs.
Miura
Hisashi
H
RIKEN Omics Science Center, RIKEN Yokohama Institute 1-7-22 Suehiro-Cho, Tsurumi-Ku, Yokohama, Kanagawa 230-0045, Japan.
Tomaru
Yasuhiro
Y
Nakanishi
Misato
M
Kondo
Shinji
S
Hayashizaki
Yoshihide
Y
Suzuki
Masanori
M
D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics; D002460:Cell Line; D017124:Conserved Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D051536:Hepatocyte Nuclear Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection; D050880:p300-CBP Transcription Factors / Q000378:metabolism
D022762:CCAAT-Enhancer-Binding Proteins; C515848:CEBPA protein, human; D051536:Hepatocyte Nuclear Factors; D014157:Transcription Factors; D004247:DNA; D050880:p300-CBP Transcription Factors