title: Klf4 is required for germ-layer differentiation and body axis patterning during Xenopus embryogenesis.
abstract: Klf4 is a transcription factor of the family of Kruppel-like factors and plays important roles in stem cell biology; however, its function during embryogenesis is unknown. Here, we report the characterization of a Klf4 homologue in Xenopus laevis during embryogenesis. Klf4 is transcribed both maternally and zygotically and the transcript is ubiquitous in embryos during germ-layer formation. Klf4 promotes endoderm differentiation in both Nodal/Activin-dependent and -independent manners. Moreover, Klf4 regulates anteroposterior body axis patterning via activation of a subset of genes in the Spemann organizer, such as Noggin, Dkk1 and Cerberus, which encode Nodal, Wnt and BMP antagonists. Loss of Klf4 function leads to the failure of germ-layer differentiation, the loss of responsiveness of early embryonic cells to inducing signals, e.g. Nodal/Activin, and the loss of transcription of genes involved in axis patterning. We conclude that Klf4 is required for germ-layer differentiation and body axis patterning by means of rendering early embryonic cells competent to differentiation signals.
authors.affiliation: Model Animal Research Center of Nanjing University and MOE Key Laboratory of Model Animals for Disease Study, 12 Xuefu Road, Pukou High-Tech Zone, 210061 Nanjing,  China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Cao
authors.forename: Xuena
authors.initials: X
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Lu
authors.forename: Linan
authors.initials: L
authors.lastname: Yang
authors.forename: Jimin
authors.initials: J
authors.lastname: Gao
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.forename: Haihua
authors.initials: H
authors.lastname: Ma
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism*; D047108:Embryonic Development / Q000235:genetics / Q000502:physiology*; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D029867:Xenopus Proteins