EFI A /YB-1 Is a Component of Cardiac HF-1A Binding Activity and Positively Regulates Transcription of the Myosin Light-Chain 2v Gene
Key result
EFIA/YB-1 binds to the HF-1a site and increased MLC-2v promoter activity by 3.4-fold in cardiac cells, mediating ventricular chamber-specific expression.
Population
Cultured ventricular muscle cells, rat neonatal heart cDNA library, rat cardiac myocyte nuclear extracts…
Design
Preclinical
Authors
Discussion
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Member takes
Implication
No immediate clinical implications; leaves open EFIA/YB-1 as a regulator of human ventricular gene expression.
Key Points
- To identify and characterize the cardiac nuclear factor that binds the HF-1a regulatory element to control ventricular chamber-specific expression of the myosin light-chain 2v (MLC-2v) gene.
- Screened a rat neonatal heart cDNA library using an HF-1a binding site probe to clone interacting proteins.
- Assessed DNA-binding specificity and endogenous complex formation using recombinant EFIA/YB-1 and anti-YB-3 antiserum in rat cardiac myocyte nuclear extracts.
- Measured transcriptional regulation via cotransfection assays with a 250-bp MLC-2v promoter construct and identified associated proteins using immunocoprecipitation.
- Recombinant EFIA/YB-1 bound sequence-specifically to the inverted CCAAT core (AGTGG) within the HF-1a site, mirroring contact points of the endogenous cardiac factor.
- EFIA/YB-1 expression stimulated 250-bp MLC-2v promoter activity by 3.4-fold in a cardiac cell-specific and HF-1a-dependent manner.
- Immunocoprecipitation identified a major associated ~30 kDa protein (p30) that forms an endogenous complex with EFIA/YB-1 at the HF-1a site.
Structured PICO
P
Population
Cultured ventricular muscle cells, rat neonatal heart cDNA library, rat cardiac myocyte nuclear extracts, and transgenic mice
I
Intervention
EFIA/YB-1 (rat homolog of human YB-1)
O
Outcome
MLC-2v promoter activity and binding to HF-1a sitesurrogate
Main Result
Effect estimate: 3.4-fold increase
EFIA/YB-1, along with a 30 kDa partner protein, binds to the HF-1a site to mediate ventricular chamber-specific expression of the MLC-2v gene.
Cite This Study
Zou et al. (1995) studied this question. EFIA/YB-1 was evaluated on MLC-2v promoter activity (3.4-fold increase). EFIA/YB-1 binds to the HF-1a site and increased MLC-2v promoter activity by 3.4-fold in cardiac cells, mediating ventricular chamber-specific expression.