title: Intermediate filament protein expression and mesoderm formation in the rabbit embryo : A double-labelling immunofluorescence study.
abstract: This study aims to describe the regulation of vimentin and cytokeratin expression during differentiation of primary mesenchymal cells in the 7 day old rabbit embryo; unusual intermediate filament protein expression patterns have already been found in this species at later embryonic stages. Double-labelling indirect immunofluorescence assays with a panel of monoclonal intermediate filament antibodies are performed on frozen sections and compared with aldehyde-fixed plastic-embedded tissues. The histological part of the study, serving as a basis for the topographical orientation in the immunostained frozen sections, emphasises many similarities between the primitive streak embryos of the rabbit and the chick. The immunohistochemical analysis reveals cytokeratin expression to varying degrees in all germ layers. Vimentin expression, always in combination with cytokeratin expression, is found in a few cells of the ectoderm, endoderm and lateral mesoderm, but not in the primary mesenchymal cells of either the primitive node or the primitive streak. The results are discussed in relation to recent experimental findings on differentiation and morphogenetic processes in the primitive streak embryo. While these complex expression patterns make it seem unlikely that intermediate filament protein subtypes are expressed independently of cellular function during development, no indication can be found for a relation between vimentin expression and the morphogenetic changes thought to be important during mesoderm formation.
authors.affiliation: Institute of Anatomy, University of Bonn, Nussallee 10, W-5300, Bonn 1, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Viebahn
authors.affiliation: CRC Cell Structure Research Group, The Cancer Research Campaign Laboratories, Department of Biochemistry, Medical Sciences Institute, The University, Dundee, UK.
authors.forename: Ellen Birgitte
authors.initials: EB
authors.lastname: Lane
authors.affiliation: Department of Molecular Cell Biology, University of Limburg, Maastricht, The Netherlands.
authors.forename: Frans Charles Servatius
authors.initials: FC
authors.lastname: Ramaekers
keywords: Cytokeratins; Gastrulation; Immunofluorescence; Rabbit; Vimentin