BAC transgenic zebrafish reveal hypothalamic enhancer activity around obesity associated SNP rs9939609 within the human FTO gene. Issue 10 (5th September 2015)

• Record Type: Journal Article
• Authors: Rinkwitz, Silke; Geng, Fan‐Suo; Manning, Elizabeth; Suster, Maximiliano; Kawakami, Koichi; Becker, Thomas S.
• Is Part Of: Genesis. Volume 53:Issue 10(2015:Oct.)
• Page Start: 640
• Page End: 651
• Publication Date: 2015-09-05
• Subjects: Developmental genetics -- Periodicals; Genetics -- Periodicals; Developmental biology -- Periodicals; Embryology -- Periodicals; Genetic regulation -- Periodicals; 576.5
• DOI: 10.1002/dvg.22884
• Languages: English
• ISSNs: 1526-954X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>Single Nucleotide Polymorphisms in <italic>FTO</italic> intron 1 have been associated with obesity risk, leading to the hypothesis that <italic>FTO</italic> is the obesity‐related gene. However, other studies have shown that the <italic>FTO</italic> gene is part of the regulatory domain of the neighboring <italic>IRX3</italic> gene and that enhancers in <italic>FTO</italic> intron 1 regulate <italic>IRX3</italic>. While <italic>Irx3</italic> activity was shown to be necessary in the hypothalamus for the metabolic function of <italic>Irx3</italic> in mouse, no enhancers with hypothalamic activity have been demonstrated in the risk‐associated region within <italic>FTO</italic>. In order to identify potential enhancers at the human <italic>FTO</italic> locus <italic>in vivo</italic>, we tested regulatory activity in <italic>FTO</italic> intron 1 using BAC transgenesis in zebrafish. A minimal <italic>gata2</italic> promoter‐GFP cassette was inserted 1.3 kb upstream of the obesity associated SNP rs9939609 in a human <italic>FTO</italic> BAC plasmid. In addition to the previously identified expression domains in notochord and kidney, human <italic>FTO</italic> BAC:GFP transgenic zebrafish larvae expressed GFP in the ventral posterior tuberculum, the posterior hypothalamus and the anterior brainstem, which are also expression domains of zebrafish <italic>irx3a</italic>. In contrast, an in‐frame insertion of a GFP cassette at the <italic>FTO</italic> start codon resulted in weak ubiquitous GFP expression indicating that the promoter of <italic>FTO</italic> does likely not react to enhancers located in the obesity risk‐associated region. genesis 53:640–651, 2015. © 2015 The Authors. genesis Published by Wiley Periodicals, Inc.</p> </abstract>