Abstract
Mice with a homozygous knockout of the jumonji (jmj) gene showed abnormal heart development and defective regulation of cardiac-specific genes, including the atrial natriuretic factor (ANF). ANF is one of the earliest markers of cardiac differentiation and a hallmark for cardiac hypertrophy. Here, we show that JMJ represses ANF gene expression by inhibiting transcriptional activities of Nkx2.5 and GATA4. JMJ represses the Nkx2.5- or GATA4-dependent activation of the reporter genes containing the ANF promoter-enhancer or containing the Nkx2.5 or GATA4-binding consensus sequence. JMJ physically associates with Nkx2.5 and GATA4 in vitro and in vivo as determined by glutathione S-transferase pull-down and immunoprecipitation assays. Using mutational analyses, we mapped the protein-protein interaction domains in JMJ, Nkx2.5, and GATA4. We identified two DNA-binding sites of JMJ in the ANF enhancer by gel mobility shift assays. However, these JMJ-binding sites do not seem to mediate ANF repression by JMJ. Mutational analysis of JMJ indicates that the protein-protein interaction domain of JMJ mediates the repression of ANF gene expression. Therefore, JMJ may play important roles in the down-regulation of ANF gene expression and in heart development.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Amino Acid Motifs
-
Animals
-
Atrial Natriuretic Factor / antagonists & inhibitors*
-
Atrial Natriuretic Factor / biosynthesis*
-
Binding Sites
-
Cell Differentiation
-
Cells, Cultured
-
DNA / chemistry
-
DNA Mutational Analysis
-
DNA Primers / chemistry
-
Enhancer Elements, Genetic
-
Fibroblasts / metabolism
-
Gene Expression Regulation, Developmental*
-
Genes, Reporter
-
Glutathione Transferase / metabolism
-
Homeobox Protein Nkx-2.5
-
Homeodomain Proteins / biosynthesis
-
Homozygote
-
Immunoprecipitation
-
Mice
-
Mice, Knockout
-
Mutation
-
Myocardium / metabolism*
-
Myocytes, Cardiac / metabolism*
-
Nerve Tissue Proteins / genetics*
-
Nerve Tissue Proteins / metabolism
-
Nerve Tissue Proteins / physiology*
-
Plasmids / metabolism
-
Polycomb Repressive Complex 2
-
Promoter Regions, Genetic
-
Protein Binding
-
Protein Biosynthesis
-
Protein Structure, Tertiary
-
Rats
-
Transcription Factors / biosynthesis
-
Transcription Factors / metabolism*
-
Transcription, Genetic*
-
Transcriptional Activation
-
Transfection
Substances
-
DNA Primers
-
Homeobox Protein Nkx-2.5
-
Homeodomain Proteins
-
Jarid2 protein, mouse
-
Nerve Tissue Proteins
-
Nkx2-5 protein, mouse
-
Transcription Factors
-
Atrial Natriuretic Factor
-
DNA
-
Polycomb Repressive Complex 2
-
Glutathione Transferase