Serum response element-like sequences of the human low density lipoprotein receptor promoter: possible regulation sites for sterol-independent transcriptional activation.
Serum factors stimulate low density lipoprotein receptor (LDLR) gene expression in HepG2 cells through sterol-independent pathways. Promoter element other than sterol regulatory element-1 (SRE-1) seems to be necessary. Protein binding activity of the human LDLR promoter fragment (550bp) beyond the SRE-1 was determined by DNase I footprint assay. Five different promoter regions were protected from DNase I digestion; -226 to -258, -291 to -304, -324 to -336, -360 to -373, and -521 to -528. The regions of -324 to -336 and -521 to -528 showed serum response element (SRE)-like consensus sequence of CC(A/T)6GG. Serum incubation affected the protection degree of the SRE-like elements, but 25-hydroxycholesterol did not. It is proposed, therefore, that the promoter region of -324 to -336 and/or -521 to -528 showed serum response elements, but 25-hydroxycholesterol did not. It is proposed, therefore, that the promoter region of -324 to -336 and/or -521 to -528 in human LDLR gene may be responsible for the rapid activation of the gene transcription by serum factor in a sterol-independent manner.
Pak
Y K
YK
Dept. of Medicine, School of Medicine, Stanford University, CA, USA.
D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D016384:Consensus Sequence / Q000235:genetics; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D006801:Humans; D006888:Hydroxycholesterols / Q000494:pharmacology; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011973:Receptors, LDL / Q000235:genetics*; D026362:Serum Response Factor; D051780:Sterol Regulatory Element Binding Protein 1; D013261:Sterols / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D006888:Hydroxycholesterols; D009687:Nuclear Proteins; D011973:Receptors, LDL; C497387:SREBF1 protein, human; D026362:Serum Response Factor; D051780:Sterol Regulatory Element Binding Protein 1; D013261:Sterols; D014157:Transcription Factors; C007997:25-hydroxycholesterol; D003850:Deoxyribonuclease I