The two isozymes of rat intestinal alkaline phosphatase are products of two distinct genes.
Rat intestinal alkaline phosphatases (IAP-I and -II) differ in primary structure, substrate specificity, tissue localization, and response to fat feeding. This study identifies two distinct genes ( approximately 5-6 kb) corresponding to each isozyme and containing 11 exons of nearly identical size. The exon-intron junctions are identical with those found in IAP genes from other species. The 1.7 and 1.2 bp of 5' flanking regions isolated from each gene, respectively, contain Sp1 and gut-enriched Kruppel-like factor (GKLF) binding sites, but otherwise show little identity. There is a potential CAAT-box 14 bp 5' to the transcriptional start site, 36 bp upstream from IAP-I, and a TATA-box 31 bp 5' to the transcriptional start site, 55 bp upstream from IAP-II. Transfection of these promoter regions (linked to luciferase as a reporter gene) into a kidney cell line, COS-7, produced the differential response to oleic acid expected from in vivo studies, i.e., threefold increase using the 5' flanking region of IAP-II, but not IAP-I. This response was not reproduced by 5,8,11,14-eicosatetraynoic acid (ETYA) or clofibrate, suggesting that peroxisome proliferator response elements are not involved. Isolation of the IAP-II gene will allow determination of the sequences responsible for dietary fat response in the enterocyte.
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Washington University School of Medicine, Division of Gastroenterology, St. Louis, Missouri 63110, USA.
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D020121:5' Untranslated Regions / Q000235:genetics; D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002994:Clofibrate / Q000494:pharmacology; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D005091:Exons; D017930:Genes, Reporter; D000960:Hypolipidemic Agents / Q000494:pharmacology; D007422:Intestines / Q000201:enzymology*; D007438:Introns; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D008969:Molecular Sequence Data; D005810:Multigene Family; D019301:Oleic Acid / Q000378:metabolism / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D020121:5' Untranslated Regions; D000960:Hypolipidemic Agents; D007527:Isoenzymes; C000715469:Klf4 protein, rat; D000090062:Kruppel-Like Factor 4; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D015117:5,8,11,14-Eicosatetraynoic Acid; D019301:Oleic Acid; C415671:Akp3 protein, rat; C415670:Alpi protein, rat; D000469:Alkaline Phosphatase; D002994:Clofibrate