title: Functional conserved elements mediate intestinal-type fatty acid binding protein (I-FABP) expression in the gut epithelia of zebrafish larvae.
abstract: Intestinal-type fatty acid binding protein (I-FABP) plays an important role in the intracellular binding and trafficking of long chain fatty acids in the intestine. The aim of this study, therefore, was to elucidate the regulation and spatiotemporal expression of the I-FABP gene during zebrafish larval development. We performed in vivo reporter-gene analysis in zebrafish by using a transient and transgenic approach. Green fluorescent protein-reporter analyses revealed that the proximal 192-bp region of the I-FABP promoter is sufficient to direct intestine-specific expression during zebrafish larval development. Functional dissection of a 41-bp region within this 192-bp promoter revealed that one C/EBP and two GATA-like binding sites, along with a novel 15-bp element within it are required for I-FABP gene expression in vivo. In addition, the six consensus sites (CCACATCAGCATGAA) in the 15-bp element are critical for I-FABP gene regulation in the zebrafish gut epithelia. Comparison analyses of the orthologous 15-bp element from mammalian I-FABP genes suggests that these mammalian elements are functionally equivalent to the zebrafish 15 element. These results provide the first in vivo evidence that these binding sites (C/EBP and GATA) and the novel 15-bp element contribute to intestine-specific gene expression and that they are functionally conserved across vertebrate evolution.
authors.affiliation: Laboratory of Marine Molecular Biology and Biotechnology, Institute of Zoology, Academia Sinica, Taipei, Taiwan, Republic of China. gmher@sinica.edu.tw
authors.forename: Guor Mour
authors.initials: GM
authors.lastname: Her
authors.forename: Yang-Hui
authors.initials: YH
authors.lastname: Yeh
authors.forename: Jen-Leih
authors.initials: JL
authors.lastname: Wu
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D017124:Conserved Sequence; D004247:DNA / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D050556:Fatty Acid-Binding Proteins; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007422:Intestines / Q000196:embryology; D007814:Larva / Q000378:metabolism*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012689:Sequence Homology, Nucleic Acid; D019076:Transgenes; D015027:Zebrafish
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D049452:Green Fluorescent Proteins; D004247:DNA