SRF-null neonatal cardiomyocytes

Serum Response Factor (SRF) is a transcriptional regulator required for mesodermal development. Numerous studies have implicated SRF as a central regulator of muscle gene expression and myogenesis. In this present study we used a loss of function approach to delineate the role of SRF in cardiac myocyte gene expression and function. In SRF null neonatal cardiomyocytes, we observe severe defects in the contractile apparatus, including Z-disc and stress fiber formation, as well as mislocalization and/or attenuation of sarcomeric proteins. Consistent with this, gene array and RT-PCR analyses show downregulation of genes encoding key cardiac transcriptional regulatory factors and proteins required for the maintenance of sarcomeric structure, function, and regulation. Chromatin IP analysis reveals that at least a subset of these proteins are likely regulated directly by SRF. Together the results presented here reveal new cellular and genetic mechanisms through which SRF exacts control over the contractile apparatus in cardiac myocytes. Keywords: genetic modification There are three control replicates (cardiomyocytes transduced with Adeno-GFP virus) and three experimental replicates (cardiomyocytes transduced with Adeno-CRE to excise SRF).