| First Author | Antes TJ | Year | 2000 |
| Journal | J Biol Chem | Volume | 275 |
| Issue | 34 | Pages | 26637-48 |
| PubMed ID | 10859308 | Mgi Jnum | J:64004 |
| Mgi Id | MGI:1888589 | Doi | 10.1074/jbc.M003025200 |
| Citation | Antes TJ, et al. (2000) Identification and characterization of a 315-base pair enhancer, located more than 55 kilobases 5' of the apolipoprotein B gene, that confers expression in the intestine. J Biol Chem 275(34):26637-48 |
| abstractText | We recently reported that an 8-kilobase (kb) region, spanning from -54 to -62 kb 5' of the human apolipoprotein B (apoB) gene, contains intestine-specific regulatory elements that control apoB expression in the intestines of transgenic mice. In this study, we further localized the apoB intestinal control region to a 3-kb segment (-54 to -57 kb). DNaseI hypersensitivity studies uncovered a prominent DNaseI hypersensitivity site, located within a 315-base pair (bp) fragment at the 5'-end of the 3-kb segment, in transcriptionally active CaCo-2 cells but not in transcriptionally inactive HeLa cells. Transient transfection experiments with CaCo-2 and HepG2 cells indicated that the 315-bp fragment contained an intestine-specific enhancer, and analysis of the DNA sequence revealed putative binding sites for the tissue-specific transcription factors hepatocyte nuclear factor 3beta, hepatocyte nuclear factor 4, and CAAT enhancer-binding protein beta. Binding of these factors to the 315-bp enhancer was demonstrated in gel retardation experiments. Transfection of deletion mutants of the 315-bp enhancer revealed the relative contributions of these transcription factors in the activity of the apoB intestinal enhancer. The corresponding segment of the mouse apoB gene (located -40 to -83 kb 5' of the structural gene) exhibited a high degree of sequence conservation in the binding sites for the key transcriptional activators and also exhibited enhancer activity in transient transfection assays with CaCo-2 cells. In transgenic mouse expression studies, the 315-bp enhancer conferred intestinal expression to human apoB transgenes. |
