title: Origin and role of distal visceral endoderm, a group of cells that determines anterior-posterior polarity of the mouse embryo.
abstract: Anterior-posterior polarity of the mouse embryo has been thought to be established when distal visceral endoderm (DVE) at embryonic day (E) 5.5 migrates toward the future anterior side to form anterior visceral endoderm (AVE). Lefty1, a marker of DVE and AVE, is asymmetrically expressed in implanting mouse embryos. We now show that Lefty1 is expressed first in a subset of epiblast progenitor cells and then in a subset of primitive endoderm progenitors. Genetic fate mapping indicated that the latter cells are destined to become DVE. In contrast to the accepted notion, however, AVE is not derived from DVE but is newly formed after E5.5 from Lefty1(-) visceral endoderm cells that move to the distal tip. Concomitant with DVE migration, all visceral endoderm cells in the embryonic region undergo global movement. In embryos subjected to genetic ablation of Lefty1-expressing DVE cells, AVE was formed de novo but the visceral endoderm including the newly formed AVE failed to migrate, indicating that DVE guides the migration of AVE by initiating the global movement of visceral endoderm cells. Future anterior-posterior polarity is thus already determined by Lefty1(+) blastomeres in the implanting blastocyst.
authors.affiliation: Developmental Genetics Group, Graduate School of Frontier Biosciences, Osaka University, and CREST, Japan Science and Technology Corporation, 1-3Yamada-oka, Suita, Osaka 565-0871, Japan. katsuo@fbs.osaka-u.ac.jp
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Takaoka
authors.forename: Masamichi
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hamada
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D001757:Blastomeres / Q000378:metabolism; D002454:Cell Differentiation; D019070:Cell Lineage; D002465:Cell Movement / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics; D016207:Cytokines; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000378:metabolism*; D004707:Endoderm / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D017403:In Situ Hybridization; D055458:Left-Right Determination Factors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D009024:Morphogenesis; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013997:Time Factors
chemical_list: C110586:Cer1 protein, mouse; D016207:Cytokines; D055458:Left-Right Determination Factors; C111386:Lefty1 protein, mouse; D011506:Proteins; D011993:Recombinant Fusion Proteins