Figure 4. Myc is required for induction of the LDHA gene in an E-box–dependent manner in response to hypertrophic agonists.
(A) Total ventricular RNA from NRVMs infected with no virus (Ctrl), AdLacZ, or AdMyc was analyzed by semiquantitative PCR for glycolytic genes (ENO-1α and LDHA) or β-actin control. (B) Schematic diagram depicting the wild-type LDHA promoter containing 2 E-boxes (E1 and E2) and 2 HIF-1α–binding (H1 and H2) sites. The E2 and H2 binding sites overlap. The mutation of the 5ι-E-box, mE1, is also shown. (C) NRVMs were transfected with either LDHA-WT or LDHA-mE1 infected with control or Myc-expressing vector. The relative luciferase activities are shown for the wild-type or mutated LDHA promoter. *P < 0.01 for LDHA-WT + Myc versus LDHA-WT without Myc or LDHA-mE1 + Myc. (D) NRVMs were transfected with either LDHA-WT or mutated promoter LDHA-mE1 and stimulated with vehicle or ET-1 for 16 hours. *P < 0.001 versus LDHA-WT without ET-1; **P < 0.01 versus LDHA-mE1 + ET-1. All data shown are representative of at least 3 independent experiments.