title: Targeted deletion of the tybe IIb Na(+)-dependent Pi-co-transporter, NaPi-IIb, results in early embryonic lethality.
abstract: NaPi-IIb encodes a Na(+)-dependent Pi co-transporter, which is expressed in various adult tissues and mediates transport of extracellular Pi ions coupling with Na(+) ion. To define the role of NaPi-IIbin vivo, NaPi-IIb gene deficient mice were generated utilizing targeted mutagenesis, yielding viable, heterozygous NaPi-IIb mice. In contrast, homozygous NaPi-IIb mice died in utero soon after implantation, indicating that NaPi-IIb was essential for early embryonic development. In situ hybridization revealed NaPi-IIb mRNA expression in the parietal endoderm, followed by the visceral endoderm, at a time point prior to establishment of a functioning chorio-allantoic placenta. At the time point of functional placenta development, the main site of NaPi-IIb production resided in the labyrinthine zone, where embryonic and maternal circulations were in closest contact. Expression patterns of NaPi-IIb suggest that NaPi-IIb plays an important role in Pi absorption from maternal circulation.
authors.affiliation: Department of Bioscience, Kitasato University School of Science, Sagamihara, Kanagawa, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Shibasaki
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Etoh
authors.forename: Michiko
authors.initials: M
authors.lastname: Hayasaka
authors.forename: Moto-o
authors.initials: MO
authors.lastname: Takahashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Kakitani
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Yamashita
authors.forename: Kazuma
authors.initials: K
authors.lastname: Tomizuka
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hanaoka
mesh_terms: D000818:Animals; D020964:Embryo Loss / Q000235:genetics*; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D015870:Gene Expression; D051379:Mice; D008817:Mice, Mutant Strains; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb / Q000235:genetics / Q000502:physiology*
chemical_list: C493558:Slc34a2 protein, mouse; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb