We report that Id knockout mouse embryos display multiple cardiac defects but mid-gestation lethality is rescued by injection of 15 wild type ES cells into mutant blastocysts. Myocardial markers altered in Id mutant cells are restored to normal throughout the chimeric myocardium. Intraperitoneal injection of ES cells into female mice prior to conception also partially rescues the cardiac phenotype with no incorporation of ES cells. IGF1, a long-range secreted factor, in combination with WNT5a, a locally secreted factor likely account for complete reversion of the cardiac phenotype. Thus, ES cells have the potential to reverse congenital defects through Id-dependent local and long-range effects in a mammalian embryo.

No abstract

No abstract

No abstract