title: Lrrc10 is a novel cardiac-specific target gene of Nkx2-5 and GATA4.
abstract: Cardiac gene expression is precisely regulated and its perturbation causes developmental defects and heart disease. Leucine-rich repeat containing 10 (Lrrc10) is a cardiac-specific factor that is crucial for proper cardiac development and deletion of Lrrc10 in mice results in dilated cardiomyopathy. However, the mechanisms regulating Lrrc10 expression in cardiomyocytes remain unknown. Therefore, we set out to determine trans-acting factors and cis-elements critical for mediating Lrrc10 expression. We identify Lrrc10 as a transcriptional target of Nkx2-5 and GATA4. The Lrrc10 promoter region contains two highly conserved cardiac regulatory elements, which are functional in cardiomyocytes but not in fibroblasts. In vivo, Nkx2-5 and GATA4 endogenously occupy the proximal and distal cardiac regulatory elements of Lrrc10 in the heart. Moreover, embryonic hearts of Nkx2-5 knockout mice have dramatically reduced expression of Lrrc10. These data demonstrate the importance of Nkx2-5 and GATA4 in regulation of Lrrc10 expression in vivo. The proximal cardiac regulatory element located at around -200bp is synergistically activated by Nkx2-5 and GATA4 while the distal cardiac regulatory element present around -3kb requires SRF in addition to Nkx2-5 and GATA4 for synergistic activation. Mutational analyses identify a pair of adjacent Nkx2-5 and GATA binding sites within the proximal cardiac regulatory element that are necessary to induce expression of Lrrc10. In contrast, only the GATA site is functional in the distal regulatory element. Taken together, our data demonstrate that the transcription factors Nkx2-5 and GATA4 cooperatively regulate cardiac-specific expression of Lrrc10.
authors.affiliation: Department of Cell and Regenerative Biology, University of Wisconsin-Madison, WI 53706, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Brody
authors.forename: Eunjin
authors.initials: E
authors.lastname: Cho
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Mysliwiec
authors.forename: Tae-Gyun
authors.initials: TG
authors.lastname: Kim
authors.forename: Clayton D
authors.initials: CD
authors.lastname: Carlson
authors.forename: Kyu-Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Youngsook
authors.initials: Y
authors.lastname: Lee
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D050991:GATA4 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D051379:Mice; D008822:Mice, Transgenic; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D050991:GATA4 Transcription Factor; C484171:Gata4 protein, mouse; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; D009124:Muscle Proteins; C484469:Nkx2-5 protein, mouse; D014157:Transcription Factors; C482740:heart-restricted leucine-rich repeat protein, mouse
keywords: Cardiac gene expression; GATA4; Lrrc10; Nkx2-5; Transcriptional regulation