The present invention relates to a new polypeptide and the gene encoding therefore, said gene being regulated in cardiac tissue by the transcription factor MEF2C. This polypeptide, CHAMP (cardiac helicase activated by MEF2 protein), bears striking resemblance to a number of other helicase proteins and appears to play a role in RNA processing and transcriptional control in heart muscle. For example, CHAMP has been demonstrated to inhibit both hypertrophy of primary cardiomyocytes and proliferation of non-cardiac cells. Also disclosed are methods of using the gene and protein in drug screening and therapy, including, for example, use of the gene in gene therapy to treat cardiovascular disease.