title: AVE protein expression and visceral endoderm cell behavior during anterior-posterior axis formation in mouse embryos: Asymmetry in OTX2 and DKK1 expression.
abstract: The initial landmark of anterior-posterior (A-P) axis formation in mouse embryos is the distal visceral endoderm, DVE, which expresses a series of anterior genes at embryonic day 5.5 (E5.5). Subsequently, DVE cells move to the future anterior region, generating anterior visceral endoderm (AVE). Questions remain regarding how the DVE is formed and how the direction of the movement is determined. This study compares the detailed expression patterns of OTX2, HHEX, CER1, LEFTY1 and DKK1 by immunohistology and live imaging at E4.5-E6.5. At E6.5, the AVE is subdivided into four domains: most anterior (OTX2, HHEX, CER1-low/DKK1-high), anterior (OTX2, HHEX, CER1-high/DKK1-low), main (OTX2, HHEX, CER1, LEFTY1-high) and antero-lateral and posterior (OTX2, HHEX-low). The study demonstrates how this pattern is established. AVE protein expression in the DVE occurs de novo at E5.25-E5.5. Neither HHEX, LEFTY1 nor CER1 expression is asymmetric. In contrast, OTX2 expression is tilted on the future posterior side with the DKK1 expression at its proximal domain; the DVE cells move in the opposite direction of the tilt.
authors.affiliation: Laboratory for Vertebrate Body Plan, Center for Developmental Biology (CDB), RIKEN Kobe, 2-2-3 Minatojima Minami-machi, Chuo-ku, Kobe 650-0046, Japan. Electronic address: hoshino@cdb.riken.jp.
authors.forename: Hideharu
authors.initials: H
authors.lastname: Hoshino
authors.affiliation: Laboratory for Animal Resources and Genetic Engineering, Center for Developmental Biology (CDB), RIKEN Kobe, 2-2-3 Minatojima Minami-machi, Chuo-ku, Kobe 650-0046, Japan. Electronic address: shioi@cdb.riken.jp.
authors.forename: Go
authors.initials: G
authors.lastname: Shioi
authors.affiliation: Laboratory for Vertebrate Body Plan, Center for Developmental Biology (CDB), RIKEN Kobe, 2-2-3 Minatojima Minami-machi, Chuo-ku, Kobe 650-0046, Japan; Laboratory for Animal Resources and Genetic Engineering, Center for Developmental Biology (CDB), RIKEN Kobe, 2-2-3 Minatojima Minami-machi, Chuo-ku, Kobe 650-0046, Japan. Electronic address: saizawa@cdb.riken.jp.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Aizawa
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D016207:Cytokines; D004707:Endoderm / Q000166:cytology / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018398:Homeodomain Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D055458:Left-Right Determination Factors / Q000378:metabolism; D008164:Luminescent Proteins; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D051857:Otx Transcription Factors / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D059008:Time-Lapse Imaging; D014157:Transcription Factors / Q000378:metabolism; D000097573:Red Fluorescent Protein
chemical_list: D016207:Cytokines; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D055458:Left-Right Determination Factors; D008164:Luminescent Proteins; D051857:Otx Transcription Factors; D011506:Proteins; D014157:Transcription Factors; D000097573:Red Fluorescent Protein; C110586:Cer1 protein, mouse; C501127:Dkk1 protein, mouse; C513080:Hhex protein, mouse; C111386:Lefty1 protein, mouse; C497660:Otx2 protein, mouse
keywords: Anterior visceral endoderm; Anterior–posterior axis; Cell lineage tracing; Dkk1; Otx2; Time-lapse imaging