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Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica
Published on: August 31, 2011
An MCM2-related gene is expressed in proliferating cells of intact and regenerating planarians
1Dipartimento di Fisiologia e Biochimica, Università di Pisa, Pisa, Italy.
Abstract:
The minichromosome maintenance (MCM2-7) gene family encodes conserved proteins, which are essential for DNA replication licensing in eukaryotes. They are abundant in proliferating cells, and specific MCM transcripts undergo cell cycle-dependent oscillations. Here we report the characterization of a planarian MCM2 homologue, DjMCM2, which represents the first molecular marker for detecting proliferating cells in planarians. DjMCM2-expressing cells are broadly distributed in the mesenchymal space of the body, with the exception of the cephalic region, and are preferentially accumulated in the peripheral area of the dorso-lateral mesenchyme, along the anteroposterior axis. During regeneration, no DjMCM2 transcripts are observed within the blastema, according to the current view that this structure is not a proliferation site in planarians. Spatio-temporal changes in DjMCM2 RNA expression pattern in the stump parallel blastema growth, coordinately with the orientation of the cut. X-ray irradiation results in the disappearance of DjMCM2 expression, thus confirming that these transcripts are detected specifically in proliferating cells, visualized as neoblasts by in situ hybridization in dissociated cells. In addition to neoblasts, rare large DjMCM2-expressing cells are observed in macerates of tissues excised just below the wound, suggesting that cell types other than neoblasts may be sporadically recruited for proliferation in planarians.
Insights
Researchers identified DjMCM2 as a novel marker for proliferating cells in planarians. This gene
Area of Science:
- Cell biology
- Developmental biology
- Regenerative medicine
Background:
- The minichromosome maintenance (MCM2-7) gene family is crucial for DNA replication licensing in eukaryotes.
- MCM proteins are abundant in proliferating cells, with cell cycle-dependent oscillations in specific MCM transcripts.
Purpose of the Study:
- To characterize the planarian MCM2 homologue, DjMCM2, as a molecular marker for proliferating cells.
- To investigate the spatial and temporal expression patterns of DjMCM2 during planarian regeneration and in response to irradiation.
Main Methods:
- In situ hybridization to detect DjMCM2 RNA expression in planarian tissues.
- X-ray irradiation to assess the specificity of DjMCM2 expression in proliferating cells.
- Analysis of dissociated cells (macerates) to identify DjMCM2-expressing cell types.
Main Results:
- DjMCM2 expression is observed in mesenchymal cells, excluding the cephalic region, with accumulation in peripheral areas.
- DjMCM2 transcripts are absent in the blastema during regeneration but show spatio-temporal correlation with stump growth.
- X-ray irradiation eliminates DjMCM2 expression, confirming its specificity for proliferating cells (neoblasts).
- Rare, large DjMCM2-expressing cells, distinct from neoblasts, were identified in tissues near the wound.
Conclusions:
- DjMCM2 serves as the first molecular marker for proliferating cells, primarily neoblasts, in planarians.
- DjMCM2 expression patterns provide insights into regeneration dynamics and cell proliferation regulation.
- Evidence suggests potential recruitment of non-neoblast cell types for proliferation in planarians.
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