Expression of the alpha-myosin heavy chain gene in the heart is regulated in part by an E-box-dependent mechanism

• Published in: The Journal of biological chemistry Vol. 268; no. 4; pp. 2602 - 2609
• Main Authors: MOLKENTIN, J. D, BROGAN, R. S, JOBE, S. M, MARKHAM, B. E
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 05-02-1993
• Subjects: Animals; Base Sequence; Biological and medical sciences; DNA-Binding Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; In Vitro Techniques; Methylation; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Mutagenesis, Site-Directed; Myocardium - metabolism; Myosins - genetics; Nuclear Proteins - metabolism; Oligodeoxyribonucleotides - chemistry; Promoter Regions, Genetic; Rats; Regulatory Sequences, Nucleic Acid; RNA, Messenger - genetics; Structure-Activity Relationship; Transcription, Genetic; Transcription. Transcription factor. Splicing. Rna processing; Heart; Vertebrata; Mammalia; Transcription; Rat; Transcription promoter; heavy-Peptide chain; Rodentia; Site directed mutagenesis; Myosin; Tissue specificity
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)53817-5

Proximal regulatory element B (PRE-B), located from positions -318 to -284 in the alpha-myosin heavy chain (MHC) promoter,
stimulated expression from an otherwise weak alpha-MHC promoter fragment in primary rat neonatal cardiomyocytes but not in
the C2C12 myogenic cell line. PRE-B interacted with alpha-MHC binding factor 2 (BF-2), a protein found in nuclear extracts
from several neonatal rat tissues and cell types including cardiomyocytes. BF-2 DNA binding activity was greatly reduced in
adult versus neonatal tissues. Methylation interference footprints indicated that BF-2 bound to an element that included an
E-box consensus sequence. Site-directed mutations in the BF-2-binding site, that abolish BF-2 binding, reduced expression
from the full-length alpha-MHC promoter by 70%. A BF-2-like protein interacts within the HF-1a element of the myosin light
chain-2 (MLC-2) promoter suggesting that one of the proteins that regulates the alpha-MHC and MLC-2 genes is identical or
closely related. Analysis of binding by competition gel shift experiments indicated that both BF-2 and HF-1a are E-box-binding
proteins. The alpha-MHC and MLC-2 genes encode contractile proteins which are precursors of myosin. Regulation by the same
transcription factor might indicate that the expression of alpha-MHC and MLC-2 is coordinately controlled.