Cell-, tissue-, and position-specific monoclonal antibodies against the planarian Dugesia (Girardia) tigrina

Abstract

To obtain specific immunological probes for studying molecular mechanisms involved in cell renewal, cell differentiation, and pattern formation in intact and regenerating planarians, we have produced a hybridoma library specific for the asexual race of the fresh-water planarian Dugesia (Girardia) tigrina. Among the 276 monoclonal antibodies showing tissue-, cell-, cell subtype-, subcellular- and position-specific staining, we have found monoclonal antibodies against all tissues and cell types with the exception of neoblasts, the undifferentiated totipotent stem-cells in planarians. We have also detected position-specific antigens that label anterior, central, and posterior regions. Patterns of expression uncovered an unexpected heterogeneity among previously thought single cell types, as well as interesting cross-reactivities that deserve further study. Characterization of some of these monoclonal antibodies suggests they may be extremely useful as molecular markers for studying cell renewal and cell differentiation in the intact and regenerating organism, tracing the origin, lineage, and differentiation of blastema cells, and characterizing the stages and mechanisms of early pattern formation. Moreover, two position-specific monoclonals, the first ones isolated in planarians, will be instrumental in describing in molecular terms how the new pattern unfolds during regeneration and in devising the pattern formation model that best fits classical data on regeneration in planarians.

The EGFR signaling pathway controls gut progenitor differentiation during planarian regeneration and homeostasis

“…The planarian gastrodermis is a monostratified epithelium composed of two cell types, absorptive phagocytes and secretory goblet cells, surrounded by an enteric muscular plexus (Bowen et al, 1974;Bueno et al, 1997;Kobayashi et al, 1998). To better characterize the loss of the gut after egfr-1 RNAi, we performed a detailed histological analysis of the gastrodermis.…”

Heterogeneity of planarian stem cells in the S/G2/M phase

“…Compared to other model organisms, available antibodies against planarian cells are scarce and directed against intracellular epitopes. Moreover, none has been described to be specific for pASCs so far (Bueno et al, 1997). It is conceivable that different planarian cell types also differ in their cell surface epitopes, which is why we opted for generating a library of mouse monoclonal antibodies against the planarian membrane proteome.…”

Autophagy meets planarians

“…6 Although neoblasts and some differentiated cells can be partially purified and cultured in vitro for some weeks, 24,25 no stable cell line has yet been developed. Some monoclonal antibodies have been produced that serve as molecular markers in planarian 26,27 and similarly, the first genes that may be candidates to control the process of regeneration have been amplified and cloned. 28,29 Although the work carried out on planarians was intense during those years, planarians have always been overshadowed by other model organisms in which gene function can be studied through the use of gain-and/or loss-of-function mutants.…”