Characterization of the human elk-1 promoter. Potential role of a downstream intronic sequence for elk-1 gene expression in monocytes.
To characterize the human elk-1 promoter, we mapped the transcriptional start site and isolated elk-1-specific genomic phage clones that contained extensive upstream and downstream sequences. A TATA-like motif was identified immediately upstream of the transcriptional start site. Functional analyses of DNA fragments containing the TATA element and the identification of a DNase I-hypersensitive chromatin site (HS 1) in close proximity to the TATA box suggest that the identified TATA motif is important for elk-1 transcription in vivo. Sequences upstream and downstream from the TATA box were found to contribute to elk-1 promoter activity. A second hypersensitive site (HS 2) was identified within the first intron in pre-monocytic cells, which express Elk-1 only when differentiating to monocytes. In a variety of other cell types, which display a constitutive Elk-1 expression, HS 2 did not exist, suggesting that inducibility of elk-1 expression is associated with the presence of HS 2. Egr-1 and the serum response factor were found to interact specifically with the intronic sequence at +265 and +448, respectively. Because Egr-1 mRNA and protein levels were observed to increase significantly before induction of elk-1 expression, we propose that Egr-1 is important for the regulation of elk-1 transcription in differentiating monocytes.
Lehmann
U
U
Institut für Molekularbiologie, Medizinische Hochschule Hannover, 30623 Hannover, Germany.
Brocke
P
P
Dittmer
J
J
Nordheim
A
A
D000818:Animals; D001483:Base Sequence; D002522:Chlorocebus aethiops; D002843:Chromatin / Q000378:metabolism; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics*; D003850:Deoxyribonuclease I / Q000378:metabolism; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D017874:Immediate-Early Proteins; D007438:Introns; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D016385:TATA Box; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D020298:U937 Cells; D050807:ets-Domain Protein Elk-1; D050808:ets-Domain Protein Elk-4
D002843:Chromatin; D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; C494112:ELK1 protein, human; C494193:ELK4 protein, human; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D050808:ets-Domain Protein Elk-4; D003850:Deoxyribonuclease I; D013755:Tetradecanoylphorbol Acetate