Overlapping Sp1 and AP2 binding sites in a promoter element of the lens-specific MIP gene
| Autor: | Chiaki Ohtaka-Maruyama, Hong Ge, Ana B. Chepelinsky, Xiao Yan Wang |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Sp1 Transcription Factor
Molecular Sequence Data DNA Footprinting DNA footprinting Regulatory Sequences Nucleic Acid Biology Transfection DNA-binding protein Bacterial Proteins Transcription (biology) Genetics Animals Humans Amino Acid Sequence Immunophilins Promoter Regions Genetic Gene Peptide sequence Transcription factor Sp1 transcription factor Binding Sites Base Sequence Membrane Proteins DNA Exons Peptidylprolyl Isomerase Molecular biology DNA-Binding Proteins Transcription Factor AP-2 Mutagenesis Regulatory sequence Chickens Gene Deletion Transcription Factors Research Article |
| Zdroj: | Nucleic Acids Research. 26:407-414 |
| ISSN: | 1362-4962 0305-1048 |
| DOI: | 10.1093/nar/26.2.407 |
| Popis: | The MIP gene, the founder of the MIP family of channel proteins, is specifically expressed in fiber cells of the ocular lens and expression is regulated temporally and spatially during development. We previously found that a DNA fragment containing 253 bp of 5'-flanking sequence and 42 bp of exon 1 of the human MIP gene contains regulatory elements responsible for lens-specific expression of the MIP gene. In this report we have analyzed the function of overlapping Sp1 and AP2 binding sites present in the MIP promoter. Using DNase I footprinting analysis we found that purified Sp1 and AP2 transcription factors interact with several domains of the human MIP promoter sequence -253/+42. Furthermore, addition of purified Sp1 to Drosophila nuclear extracts activates in vitro transcription from the MIP promoter -253/+42. This promoter activity is competed by oligonucleotides containing domains footprinted with Sp1. Using promoter-reporter gene ( CAT ) constructs we found that the sequence -39/-70 contains a cis regulatory element essential for promoter activity in transient assays in lens cells. EMSA analysis showed that lens nuclear extracts contain factors that bind to the MIP 5'-flanking sequence containing overlapping Sp1 and AP2 binding domains at positions -37/-65. Supershift experiments with lens nuclear extracts indicated that Sp3 is also able to interact with this regulatory element, suggesting that Sp1 and Sp3 may be involved in regulation of transcription of the MIP gene in the lens. |
| Databáze: | OpenAIRE |
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