Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.99.3 (PRE)
 1,923 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies have documented that 250 bp of the rat cardiac ventricular myosin light-chain 2 (MLC-2v) promoter is sufficient to confer cardiac muscle-specific expression on a luciferase reporter gene in both transgenic mice and primary cultured neonatal rat myocardial cells. Utilizing ligation-mediated PCR to perform in vivo dimethyl sulfate footprinting, the present study has identified protein-DNA interaction within the position from -176 to -165. This region, identified as MLE1, contains a core sequence, CACGTG, which conforms to the consensus E-box site and is identical to the upstream stimulating factor (USF)-binding site of the adenovirus major late promoter. Transient assays of luciferase reporter genes containing point mutations of the site demonstrate the importance of this cis regulatory element in the transcriptional activation of this cardiac muscle gene in ventricular muscle cells. The protein complex that occupies this site is capable of binding to HF-1a and PRE B sites which are known to be required for cardiac muscle-specific expression of rat MLC-2v and alpha-myosin heavy-chain genes, respectively. This study provides direct evidence that USF, a member of the basic helix-loop-helix leucine zipper family, binds to MLE1, HF-1a, and PRE B sites and suggests that it is a component of protein complexes that may coordinately control the expression of MLC-2v and alpha-myosin heavy-chain genes. The current study also provides evidence that USF can positively and negatively regulate the MLC-2v gene via independent cis regulatory elements.
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PMID:The basic helix-loop-helix protein upstream stimulating factor regulates the cardiac ventricular myosin light-chain 2 gene via independent cis regulatory elements. 793 47

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.
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PMID:Expression of the alpha-myosin heavy chain gene in the heart is regulated in part by an E-box-dependent mechanism. 842 36