Generation of a reporter-null allele of Ppap2b/Lpp3and its expression during embryogenesis.

Our knowledge of how bioactive lipids participate during development has been limited principally due to the difficulties of working with lipids. The availability of some of these lipids is regulated by the Lipid phosphate phosphatases (LPPs). The targeted inactivation of Ppap2b, which codes for the isoenzyme Lpp3, has profound developmental defects. Lpp3 deficient embryos die around E9.5 due to extraembryonic vascular defects, making difficult to analyze its participation in later stages of mouse development. To gain some predictive information regarding the possible participation of Lpp3 in later stages of development, we generated a Ppap2b null reporter allele and it was used to establish its expression pattern in E8.5-13.5 embryos. We found that Ppap2b expression during these stages was highly dynamic with significant expression in structures where multiple inductive interactions occur such as the limb buds, mammary gland primordia, heart cushions and valves among others. These observations suggest that Lpp3 expression may play a key role in modulating/integrating multiple signaling pathways during development.