title: Srf(-/-) ES cells display non-cell-autonomous impairment in mesodermal differentiation.
abstract: The serum response factor (SRF) transcription factor is essential for murine embryogenesis. SRF+(-/-) embryos stop developing at the onset of gastrulation, lacking detectable mesoderm. This developmental defect may reflect cell-autonomous impairment of SRF(-/-) embryonic cells in mesoderm formation. Alternatively, it may be caused by a non-cell-autonomous defect superimposed upon inappropriate provision of mesoderm-inducing signals to primitive ectodermal cells. We demonstrate that the ability of SRF(-/-) embryonic stem (ES) cells to differentiate in vitro into mesodermal cells is indeed impaired. However, this impairment can be modulated by external, cell-independent factors. Retinoic acid, but not dimethylsulfoxide, permitted activation of the mesodermal marker gene T(Bra), which was also activated when SRF was expressed in SRF(-/-) ES cells. Embryoid bodies from SRF(-/-) ES cell aggregates also activated mesodermal marker genes, but displayed unusual morphologies and impairment in cavitation. Finally, in nude mice, Srf(-/-) ES cells readily differentiated into mesodermal cells of SRF(-/-) genotype, including cartilage, bone or muscle cells. We demonstrate that SRF contributes to mesodermal gene expression of ES cells and that SRF(-/-) ES cells display a non-cell-autonomous defect in differentiation towards mesoderm.
authors.affiliation: Institut für Molekularbiologie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Weinhold
authors.forename: G
authors.initials: G
authors.lastname: Schratt
authors.forename: S
authors.initials: S
authors.lastname: Arsenian
authors.forename: J
authors.initials: J
authors.lastname: Berger
authors.forename: K
authors.initials: K
authors.lastname: Kamino
authors.forename: H
authors.initials: H
authors.lastname: Schwarz
authors.forename: U
authors.initials: U
authors.lastname: Rüther
authors.forename: A
authors.initials: A
authors.lastname: Nordheim
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D002478:Cells, Cultured; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D005819:Genetic Markers; D008648:Mesoderm / Q000166:cytology*; D051379:Mice; D018345:Mice, Knockout; D008855:Microscopy, Electron, Scanning; D009687:Nuclear Proteins / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D026362:Serum Response Factor; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D014157:Transcription Factors / Q000172:deficiency* / Q000235:genetics / Q000502:physiology
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; D005819:Genetic Markers; D009687:Nuclear Proteins; D026362:Serum Response Factor; D014157:Transcription Factors