title: Maternal control of axial-paraxial mesoderm patterning via direct transcriptional repression in zebrafish.
abstract: Axial-paraxial mesoderm patterning is a special dorsal-ventral patterning event of establishing the vertebrate body plan. Though dorsal-ventral patterning has been extensively studied, the initiation of axial-paraxial mesoderm pattering remains largely unrevealed. In zebrafish, spt cell-autonomously regulates paraxial mesoderm specification and flh represses spt expression to promote axial mesoderm fate, but the expression domains of spt and flh initially overlap in the entire marginal zone of the embryo. Defining spt and flh territories is therefore a premise of axial-paraxial mesoderm patterning. In this study, we investigated why and how the initial expression of flh becomes repressed in the ventrolateral marginal cells during blastula stage. Loss- and gain-of-function experiments showed that a maternal transcription factor Vsx1 is essential for restricting flh expression within the dorsal margin and preserving spt expression and paraxial mesoderm specification in the ventrolateral margin of embryo. Chromatin immunoprecipitation and electrophoretic mobility shift assays in combination with core consensus sequence mutation analysis further revealed that Vsx1 can directly repress flh by binding to the proximal promoter at a specific site. Inhibiting maternal vsx1 translation resulted in confusion of axial and paraxial mesoderm markers expression and axial-paraxial mesoderm patterning. These results demonstrated that direct transcriptional repression of the decisive axial mesoderm gene by maternal ventralizing factor is a crucial regulatory mechanism of initiating axial-paraxial mesoderm patterning in vertebrates.
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou 310058, Zhejiang, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou 310058, Zhejiang, People's Republic of China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Xu
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou 310058, Zhejiang, People's Republic of China.
authors.forename: Shufang
authors.initials: S
authors.lastname: Zhao
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou 310058, Zhejiang, People's Republic of China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Ma
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou 310058, Zhejiang, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou 310058, Zhejiang, People's Republic of China.
authors.forename: Zhenghua
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Life Science, Zhejiang University, Hangzhou 310058, Zhejiang, People's Republic of China. Electronic address: luoc@zju.edu.cn.
authors.forename: Chen
authors.initials: C
authors.lastname: Luo
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D019521:Body Patterning; D005136:Eye Proteins / Q000235:genetics; D005260:Female; D005775:Gastrula / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics; D008648:Mesoderm / Q000378:metabolism*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020825:T-Box Domain Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; D020825:T-Box Domain Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C096660:noto protein, zebrafish; C112539:tbx16 protein, zebrafish; C108838:vsx1 protein, zebrafish; D049452:Green Fluorescent Proteins
keywords: Axial–paraxial mesoderm patterning; Direct transcription repression; Maternal control; Vsx1