Construction and functional analysis of BNP promoter luciferase reporter plasmid

Abstract

The re-expression of a fetal cardiac gene program, including bran natriuretic peptide (BNP), contributes to the development of cardiac hypertrophy. The mRNA and protein expression of BNP are increased in hypertrophic and failing hearts. Myocardin, a co-activator of serum response factor (SRF), potently transactivates hypertrophic genes via binding the CArG box within the promoter of these hypertrophic genes and induces cardiomyocyte hypertrophy. The neuronrestrictive silencer factor (NRSF), also known as RE-1 silencing transcription factor (REST), has been shown to negatively regulate the gene transcription of BNP by binding to a neuron-restrictive silencer element (NRSE). In the present study, the gene fragment of human BNP gene promoter containing two CArG boxes and one NRSE was cloned into empty vector pGL3-Basic to construct BNP promoter luciferase reporter plasmid. Myocardin expression plasmids or NRSF expression plasmids were co-transfected with BNP promoter-luc plasmids into COS-7 cells to analyze the regulatory effects of myocardin and NRSF on the promoter activity of BNP. The results showed that myocardin over-expression significantly up-regulated the activity of BNP promoter, while NRSF inhibited myocardin-induced activation of BNP promoter. The results suggest that NRSF may play a critical role in regulating BNP gene in cardiac hypertrophy and heart failure.