ZFIN ID: ZDB-PUB-050929-1
T-box binding sites are required for activity of a cardiac GATA-4 enhancer
Heicklen-Klein, A., and Evans, T.
Date: 2004
Source: Developmental Biology   267(2): 490-504 (Journal)
Registered Authors: Evans, Todd
Keywords: Zebrafish, Transcriptional regulation, Valves, Transgenic, Heart development, T-box
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Blotting, Southern
  • DNA Primers
  • DNA-Binding Proteins/genetics*
  • DNA-Binding Proteins/metabolism*
  • GATA4 Transcription Factor
  • Gene Components
  • Gene Expression Regulation, Developmental*
  • Green Fluorescent Proteins
  • Heart/embryology*
  • In Situ Hybridization
  • Luminescent Proteins/metabolism
  • Microinjections
  • Mutagenesis, Site-Directed
  • Promoter Regions, Genetic/genetics
  • T-Box Domain Proteins/genetics
  • T-Box Domain Proteins/metabolism*
  • Transcription Factors/genetics*
  • Transcription Factors/metabolism*
  • Zebrafish
PubMed: 15013808 Full text @ Dev. Biol.
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ABSTRACT
GATA-4 is a key regulator of a poorly understood cardiac morphogenetic program. We used genomic regions of the GATA-4 gene to target GFP expression to the developing heart of living fish. In these fish, GFP-expressing cells in the lateral plate mesoderm form two tubes that migrate ventrally to fuse into a linear heart tube. In addition, we find that a 14.8-kb fragment upstream of the transcription initiation site targets expression to both chambers and the valves of the heart. Truncation of 7 kb of the distal sequences eliminates expression in the atrium and the atrioventricular valve while expression is retained in the ventricle and the bulboventricular valve. Within this 7-kb distal regulatory region, we delineated a 1300-bp region with a cluster of consensus binding sites for T-box transcription factors. Mutation of these sequences significantly reduces reporter gene expression in the heart. This provides the first evidence that T-box factors function by directly regulating GATA-4 expression. Thus, GATA-4 regulatory elements control gene expression differentially along the rostro-caudal axis, and T-box binding elements in the GATA-4 promoter contribute to heart-specific expression.
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