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Table 2 Definition of a common framework consisting of different transcription factor binding sites by analyzing 32 promoters of Aroclor 1254-regulated genes (transcription factors and genes involved in cell cycle regulation and apoptosis) using the Genomatix software FrameWorker. Only these promoters were applied, which possess at least one AhR binding site in its promoter, in order to identify candidate transcription factors which might cooperate with the AhR and in order to identify a common framework for promoters regulated by the AhR.

From: Transcriptome profiling of human hepatocytes treated with Aroclor 1254 reveals transcription factor regulatory networks and clusters of regulated genes

AROCLOR 1254-INDUCED GENES (14 SEQUENCES)

AROCLOR 1254-REPRESSED GENES (18 SEQUENCES)

100%

90%

100%

90%

AhR

 

AhR

 

ETS

 

ETS

 

SP1

 

SP1

 
  

E2F

 
 

CREB

 

CREB

 

EGR

 

EGR

 

ZBP

 

ZBP

 

NF-kB

 

NF-kB

 

NKXH

 

NKXH

   

MAZ

   

HOX

   

WHZ

 

ECAT

  
 

TBP

  
  1. Binding sites of transcription factors which were identified in Aroclor 1254-induced promoters are marked in red, whereas binding sites of transcription factors which were identified in Aroclor 1254-repressed promoters are marked in blue. Binding sites of transcription factors which were present in the corresponding frequency (100 or 90%) in only induced or repressed promoters are underlined. These transcription factor binding sites discriminate induced from repressed promoters and vice versa. ETS: ETS transcription factors are known to regulate cellular growth and differentiation. SP1: SP1 transcription factors are ubiquitous and bind to GC-rich sequences in a large number of promoters. They can modulate transcription of specific genes through interactions with cell type- or stage-specific transcription factors. E2F: The E2F family plays a crucial role in the control of cell cycle. CREB: cyclic AMP (cAMP) response element-binding protein is a ubiquitous transcription factor that functions in glucose homeostasis and stimulates the expression of numerous genes in response to growth factors, hormones, neurotransmitters, ion fluxes and stress signals. EGR: EGR transcription factors are known to activate genes which are involved in differentiation and mitogenesis. ZBP: ZBP transcription factors are known to activate genes which are involved in cell growth arrest and cell death. NF-kB: cytokine- or stress-activated and stimulates the expression of genes involved in a wide variety of biological functions. NKXH: NKX homeodomain factors play critical roles in regulating tissue-specific gene expression essential for tissue differentiation. MAZ: Myc-associated zinc fingers are ubiquitously expressed and can exert positive and negative control over the expression of target genes. HOX: The homeobox genes encode a highly conserved family of transcription factors that play an important role in morphogenesis. WHZ: Winged helix protein, involved in hair keratinization and thymus epithelium differentiation. ECAT: Enhancer CCAAT binding factors. A trimeric complex (nuclear factors YA-C (Y-box binding factors)), forming a highly conserved, ubiquitously expressed transcription factor that binds with high specificity to CCAAT motifs in the promoter regions in a variety of genes. TBP: TATA-binding protein factor binds directly to the promoter and nucleates the assembly of a transcriptionally competent preinitiation complex.