title: Regulation of mesodermal precursor production by low-level expression of B1 Sox genes in the caudal lateral epiblast.
abstract: High expression of the B1 Sox genes, Sox2 and Sox3, is associated with the development of definitive neural primordia, the neural plates, in early stage embryos. However, in the caudal lateral epiblast (CLE) where axial stem cells reside, Sox2 and Sox3 are expressed at low levels, together with Brachyury. Because axial stem cells are the bipotential precursors of the neural plate and paraxial mesoderm, we investigated the possibility that low-level B1 Sox expression in CLE may regulate the fate of axial stem cells. We combined the genetic conditions of Sox3-null and Sox2 N1 enhancer homozygous deletion (Sox2(ΔN1/ΔN1)) to decrease B1 Sox expression in CLE. At 5-7 somite stages of mouse embryogenesis, these genetic manipulations caused approximately 30% higher production of paraxial mesodermal precursors, resulting in the development of larger somites. Analysis of mitotic cell populations suggested that decrease of B1 Sox expression in CLE does not activate cell proliferation but promotes cell migration into the mesodermal compartment. Thus, the low-level B1 Sox expression in CLE regulates axial stem cells to adjust the production of paraxial mesoderm precursors to an appropriate level.
authors: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Megumi
authors: M
authors: Yoshida
authors: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Masanori
authors: M
authors: Uchikawa
authors: National Institute for Medical Research, London NW7 1AA, UK.
authors: Karine
authors: K
authors: Rizzoti
authors: National Institute for Medical Research, London NW7 1AA, UK.
authors: Robin
authors: R
authors: Lovell-Badge
authors: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; Fujii Memorial Institute of Medical Sciences, The University of Tokushima, 3-18-5 Kuramoto-cho, Tokushima 770-8503, Japan.
authors: Tatsuya
authors: T
authors: Takemoto
authors: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address: kondohh@fbs.osaka-u.ac.jp.
authors: Hisato
authors: H
authors: Kondoh
mesh_terms: D000818:Animals; D047108:Embryonic Development / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D005855:Germ Layers / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D054258:Neural Plate / Q000378:metabolism*; D055748:SOXB1 Transcription Factors / Q000235:genetics* / Q000378:metabolism; D019170:Somites / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism
chemical_list: D055748:SOXB1 Transcription Factors
keywords: Axial stem cells; Caudal lateral epiblast; Paraxial mesodermal precursors; Sox2; Sox3