Cardiosensor mice and transcriptional subdomains of the vertebrate heart

Differential regulation of cardiac gene expression in vertebrates has been extensively documented in the context of atrial and ventricular morphogenes is. Recent data, largely from the analysis of transgene and endogenous gene expression patterns, have revealed transcriptional differences between lef t and right cardiac chambers which suggest that the heart is composed of a series of distinct transcriptional domains. Such phenomena provide regional markers (cardiosensors) for the fine analysis of normal and abnormal heart development. Regional subdivisions and transcriptional heterogeneity withi n the myocardium emerge in response to patterning of the precardiac mesoder m and early heart tube on the anterior-posterior axis, and to embryonic lef t-right signals which dictate the direction of cardiac looping. Several fam ilies of transcription factors have been characterized which may be implica ted in the regionalization of myocardial gene expression. (C) 1999, Elsevie r Science Inc.