Mice heterozygous for this targeted mutation are viable and fertile. Mice homozygous for this targeted allele, however, die between embryonic day (E) 9.5 and 10.5 due to cardiomyocyte maturation defects, including an enlarged heart, single left-side ventricular chamber with tremendous extra cellular matrix expansion between the myocardial and endocardial layers, and defective Hand2 expression. No mRNA transcripts from the targeted mutant gene are detected in cardiac tissue from E9.5 homozygotes. These mutant mice may be useful in studying cardiomyocyte differentiation and cardiac morphogenesis.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
