Voltage-gated T-type Ca2+ channels (T-channels) are highly expressed in embryonic but undetectable in adult ventricular myocytes. Interestingly, T-channels are reexpressed in hypertrophied or failing hearts. It has been shown that Cav3.2 T-channel is involved in the pathogenesis of cardiac hypertrophy via the activation of calcineurin/nuclear factor of activated T cells (NFAT) pathway (Chiang et al, 2009). However, it is unclear when and how Cav3.2 is induced during cardiac hypertrophy. Because the mRNA re-expression is mainly through the transcriptional regulation in the promoter or enhancer conserved in different species, we hypothesized that the evolutionary conserved promoter (ECP) of Cav3.2 carries important binding sites for transcription factors that regulate its re-expression in the hypertrophic hearts. In this study, we obtained the ECP of Cav3.2 by aligning Cav3.2 genes from different species. By fusing mouse ECP with the reporter gene firefly luciferase, we showed that the ECP drove high luciferase activity in the cells expressing endogenous Cav3.2 but not in the one without Cav3.2. To further validate ECP in vivo, we generated transgenic mice expressing luciferase reporter driven by Cav3.2 ECP (Tg-Cav3.2-Luc). Analysis of the Tg-Cav3.2-Luc mice showed that ECP confers the reporter expression similar to the endogenous Cav3.2 in the tissue distribution, development of hearts, and most importantly, the inducibility of hypertrophic stimulation. The left ventricular luciferase activity can be induced as early as 3 days after pressure overload created by trans-aortic banding (TAB) surgery (Chiang et al, 2009). By injecting reporters driven by different truncated promoters followed by TAB surgery, the hypertrophic regulatory element was located within -420 bp relative to the transcription start site (TSS) of Cav3.2. We searched the putative TF binding sites within the proximal 420 bp of mouse Cav3.2 5′-flanking sequence (Cav3.2-420) using the TFSEARCH and confirmed that early growth response 1 (Egr1) is the important transcription factor to enhance Cav3.2 gene expression. We showed the Egr1 could bind to the -81 to -41 bp upstream of Cav3.2 TSS using MESA and Chip assays. The protein level of Egr1 in left ventricle was also upregulated at 3 days after TAB, the same time point when the Cav3.2-Luc was induced in Tg-Cav3.2-Luc. To demonstrate that Egr1 indeed regulates Cav3.2 expression after hypertrophic stimulation, we showed that knockdown of Egr1 using siRNA prevented the phenylephrine (PE)-induced upregulation of Egr1, Cav3.2 and cellular hypertrophy in H9C2 cells. Furthermore, overexpression of Cav3.2 in Egr1 knockdown cells restored the PE-induced hypertrophy. In conclusion, our results demonstrate that Egr1 regulates the expression of Cav3.2 T-type calcium channel in cardiac hypertrophy.