title: Transcriptomic landscape of the primitive streak.
abstract: In birds and mammals, all mesoderm cells are generated from the primitive streak. Nascent mesoderm cells contain unique dorsoventral (D/V) identities according to their relative ingression position along the streak. Molecular mechanisms controlling this initial phase of mesoderm diversification are not well understood. Using the chick model, we generated high-quality transcriptomic datasets of different streak regions and analyzed their molecular heterogeneity. Fifteen percent of expressed genes exhibit differential expression levels, as represented by two major groups (dorsal to ventral and ventral to dorsal). A complete set of transcription factors and many novel genes with strong and region-specific expression were uncovered. Core components of BMP, Wnt and FGF pathways showed little regional difference, whereas their positive and negative regulators exhibited both dorsal-to-ventral and ventral-to-dorsal gradients, suggesting that robust D/V positional information is generated by fine-tuned regulation of key signaling pathways at multiple levels. Overall, our study provides a comprehensive molecular resource for understanding mesoderm diversification in vivo and targeted mesoderm lineage differentiation in vitro.
authors.affiliation: Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Hyogo, Japan.
authors.forename: Cantas
authors.initials: C
authors.lastname: Alev
authors.forename: Yuping
authors.initials: Y
authors.lastname: Wu
authors.forename: Takeya
authors.initials: T
authors.lastname: Kasukawa
authors.forename: Lars M
authors.initials: LM
authors.lastname: Jakt
authors.forename: Hiroki R
authors.initials: HR
authors.lastname: Ueda
authors.forename: Guojun
authors.initials: G
authors.lastname: Sheng
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000235:genetics; D019521:Body Patterning / Q000235:genetics; D019485:Bone Morphogenetic Proteins / Q000235:genetics; D002642:Chick Embryo; D002874:Chromosome Mapping; D005346:Fibroblast Growth Factors / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D008648:Mesoderm / Q000196:embryology / Q000378:metabolism; D005810:Multigene Family; D020411:Oligonucleotide Array Sequence Analysis; D054240:Primitive Streak / Q000196:embryology* / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000235:genetics; D051153:Wnt Proteins / Q000235:genetics
chemical_list: D030161:Avian Proteins; D019485:Bone Morphogenetic Proteins; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D051153:Wnt Proteins; D005346:Fibroblast Growth Factors