title: Transcriptional profiling of the developmentally important signalling pathways in human embryonic stem cells.
abstract: BACKGROUND
  Embryonic stem cells (ESC) maintain their 'stemness' by self-renewal. However, the molecular mechanisms underlying self-renewal of human embryonic stem cells (hESC) remain to be elucidated. In this study, expression profiles of the molecules of developmentally important signalling pathways were investigated to better understand the relationships of the signalling pathways for self-renewal in hESC.
  
  
  METHODS
  Two human ESC lines were cultured on mouse embryonic fibroblast (MEF) feeder cells. Gene expression was analysed by RT-PCR, real-time RT-PCR and Western blotting.
  
  
  RESULTS
  In the bone morphogenetic protein (BMP4), transforming growth factor (TGF-beta) and fibroblast growth factor (FGF4) signalling pathways, ligands and antagonists were highly expressed in hESC compared with human embryoid body (hEB). Human ESC showed abundant transcripts of intracellular molecules in the Wnt, Hh and Notch signalling pathways. No difference was detected in the expression level of the JAK/STAT signalling molecules between hESC and hEB. Western blot analysis showed that the transcriptional levels of the signalling molecules in hESC were consistent with translational levels. From the real-time PCR analysis, expression levels of some genes, such as Oct3/4, Nodal and beta-catenin, were different between two hESC lines.
  
  
  CONCLUSIONS
  The self-renewal of hESC is probably maintained by coordinated regulation of signalling-specific molecules and in a signalling-specific manner.
authors.affiliation: Laboratory of Development and Differentiation, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 52 Eoeun-dong Yuseong-gu, Daejeon 305-806, Korea.
authors.forename: Jeung-Yon
authors.initials: JY
authors.lastname: Rho
authors.forename: Kweon
authors.initials: K
authors.lastname: Yu
authors.forename: Jee-Soo
authors.initials: JS
authors.lastname: Han
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Chae
authors.forename: Deog-Bon
authors.initials: DB
authors.lastname: Koo
authors.forename: Hyun-Soo
authors.initials: HS
authors.lastname: Yoon
authors.forename: Shin-Yong
authors.initials: SY
authors.lastname: Moon
authors.forename: Kyung-Kwang
authors.initials: KK
authors.lastname: Lee
authors.forename: Yong-Mahn
authors.initials: YM
authors.lastname: Han
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D004622:Embryo, Mammalian / Q000166:cytology* / Q000378:metabolism; D047108:Embryonic Development; D051519:Fibroblast Growth Factor 4 / Q000378:metabolism; D020869:Gene Expression Profiling; D053823:Hedgehog Proteins; D006801:Humans; D051379:Mice; D008954:Models, Biological; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050791:STAT Transcription Factors / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: C525809:BMP4 protein, human; C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; C496445:FGF4 protein, human; D051519:Fibroblast Growth Factor 4; D053823:Hedgehog Proteins; D012333:RNA, Messenger; D051880:Receptors, Notch; D050791:STAT Transcription Factors; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D051153:Wnt Proteins; D011505:Protein-Tyrosine Kinases