Atrial Natriuretic Factor-SV40 T Antigen Transgenes Produce Tumors and Cardiac Arrhythmias in Mice

Transgenic mice that carry fusions between the transcriptional regulatory sequences of atrial natriuretic factor (a hormone intimately involved in the regulation of blood pressure) and those encoding SV40 T antigen (an oncoprotein) were generated. Although both atria express the fusion gene, the pathological response to T antigen is asymmetrical. The right atrium undergoes a several hundredfold increase in mass while the left atrium remains relatively normal in size. Hyperplasia is accompanied by a progressive increase in both the frequency and severity of abnormalities in the atrial conduction system, which ultimately result in death.