Planarian pharynx regeneration in regenerating tail fragments monitored with cell-specific monoclonal antibodies |
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Authors: | D Bueno Lluis Espinosa Jaume Baguñà Rafael Romero |
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Institution: | (1) Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, E-08071 Barcelona, Catalonia, Spain, ES |
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Abstract: | The special morphological features of freshwater planarians make them an attractive and informative model for studying the
processes of regeneration and pattern formation. In this work, we investigate pattern formation and maturation of the planarian
pharynx during regeneration in tail fragments. Using three monoclonal antibodies (TCAV-1, TF-26 and TMUS-13) specific for
epithelial, secretory and muscle cells, respectively, we followed the sequence and timing of differentiation and maturation
of these three cell types within the regenerating pharynx. Two of these monoclonal antibodies, TCAV-1 and TMUS-13, also labelled
morphologically immature cells that appear to be committed to the differentiation pathway leading to their respective adult
cell types. Our results show that the cells forming the new pharynx come from undifferentiated cells through proliferation
and differentiation processes rather than from differentiated cells of the old stump. We describe three stages of pharynx
regeneration according to the immunoreactivity shown: (1) no immunoreactivity, corresponding to the accumulation of undifferentiated
cells that form the pharynx primordium; (2) immunoreactivity to TCAV-1 and TMUS-13, corresponding to the re-building of the
pharynx; and (3) immunoreactivity to TF-26, corresponding to a fully mature and functional pharynx. The sequence of differentiation
of these three cell types suggests that the pharynx grows by intercalation of new undifferentiated cells coming from the parenchyma
between the older pharyngeal cells, in agreement with existing models of pharynx regeneration. Finally, our results suggest
an intercalary model for pharynx epithelial cell renewal.
Received: 30 September 1996 / Accepted: 6 December 1996 |
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Keywords: | Planaria Pattern formation Pharynx regeneration Cell renewal Monoclonal antibodies |
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