Not your father's planarian: a classic model enters the era of functional genomics

  title={Not your father's planarian: a classic model enters the era of functional genomics},
  author={Phillip A. Newmark and Alejandro S{\'a}nchez Alvarado},
  journal={Nature Reviews Genetics},
Freshwater planarians were a classic model for studying the problems of development and regeneration. However, as attention shifted towards animals with more rigid developmental processes, the planarians, with their notoriously plastic ontogeny, declined in significance as a model system. This trend was exacerbated with the introduction of genetic and molecular approaches, which did not work well in planarians. More recently, the heightened interest in stem-cell biology, along with the… 

The freshwater planarian Schmidtea mediterranea: embryogenesis, stem cells and regeneration.

This work has shown how the isolation of thousands of expressed sequence tags and the introduction of in situ hybridizations, immunocytology, and RNA-mediated gene interference has opened the door to gene discovery and to the study of gene function in planarians during development and regeneration.

Evolution and regeneration of the planarian central nervous system

This work has identified a gene, nou‐darake, which directs the formation of a proper extrinsic environment for pluripotent stem cells to differentiate into brain cells in the planarian Dugesia japonica.

Emerging patterns in planarian regeneration.

Planarians: a versatile and powerful model system for molecular studies of regeneration, adult stem cell regulation, aging, and behavior.

An overview of the planarian model system with special attention to the species Schmidtea mediterranea is provided about the most popular use of this organism, together with modern genomic resources and technical approaches.

Model systems for regeneration: planarians

This Primer provides an overview of planarians as a model system for studying regeneration, highlighting the tools and techniques available for examining planaria and discussing how the study of planarian can help address broader questions about regenerative mechanisms.

The power of regeneration and the stem-cell kingdom: freshwater planarians (Platyhelminthes).

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  • Biology
    BioEssays : news and reviews in molecular, cellular and developmental biology
  • 2006
Genomic and proteomic data are essential in answering some of the fundamental questions concerning this remarkable morphological plasticity of freshwater planarians, and should pave the way to understanding the genetic pathways associated with metazoan somatic stem-cell regulation and pattern formation.

Does regeneration recapitulate phylogeny? Planaria as a model of body-axis specification in ancestral eumetazoa

It is suggested that asexual planaria forms may point toward an ancestral eumetazoan form with characteristics of both cnidarians and placazoa, as well as in many bilaterians, tertiary body axes with structural asymmetries at multiple scales.

Are Planaria Individuals? What Regenerative Biology is Telling Us About the Nature of Multicellularity

It is suggested that planaria have not fully completed the transition to multicellularity, but instead represent an intermediate form in which a small number of genetically-heterogeneous, reproductively-competent cells effectively “farm” their reproductive offspring.

Regenerative tissue remodeling in planarians - The mysteries of morphallaxis.




Planarian Hox genes: novel patterns of expression during regeneration.

Sequence analyses of seven planarian Dthox genes reveal high similarities with the homeodomain region of the Hox cluster genes, allowing us to assign planarian Hox-related genes to anterior and medial Hox clusters paralogous groups.

Double-stranded RNA specifically disrupts gene expression during planarian regeneration.

The ability to eliminate gene function in a regenerating organism such as the planarian overcomes previous experimental limitations and opens the study of animal regeneration to unprecedented levels of molecular detail.

A planarian orthopedia homolog is specifically expressed in the branch region of both the mature and regenerating brain

The results suggest that recruitment of Otp for its role in brain pattern formation occurred very early in evolution.

Dissecting planarian central nervous system regeneration by the expression of neural‐specific genes

The results from this study show that the comparison of the expression patterns of different neural genes supports the view that at day one of regeneration, the new brain appears within the blastema, whereas the pre‐existing ventral nerve cords remain in the old tissues.

Searching for the prototypic eye genetic network: Sine oculis is essential for eye regeneration in planarians.

The results suggest that the same basic gene regulatory circuit required for eye development in Drosophila and mouse is used in the prototypic eye spots of platyhelminthes and, therefore, is truly conserved during evolution.

Position‐specific and non‐colinear expression of the planarian posterior (Abdominal‐B‐like) gene

These findings suggest the possibility that DjAbd‐Ba is involved in the specification of the tail region, and expression patterns of planarian Hox genes seem out of the rule of spatial colinearity and may reflect an ancestral feature of bilaterian H Cox genes.

Growth, Degrowth and Regeneration as Developmental Phenomena in Adult Freshwater Planarians

Freshwater planarians are the best known planarians due to there easy culture and ease of handling under laboratory conditions and, because they have been, and still are, the most widely used turbellarian in experimental research, particularly with regards to regeneration.

Mitosis in the intact and regenerating planarian Dugesia mediterranea n.sp. I. Mitotic studies during growth, feeding and starvation

Planarian neoblasts, the only cell type in this organism endowed with mitotic power, decrease in density as total body volume, total cell number, and length increase. Studies on mitosis show that the

Bromodeoxyuridine specifically labels the regenerative stem cells of planarians.

The ability to label specifically the regenerative stem cells, combined with the recently described use of double-stranded RNA to inhibit gene expression in the planarian, should serve to reignite interest in the flatworm as an experimental model for studying the problems of metazoan regeneration and the control of stem cell proliferation.

Cellular and Molecular Basis of Regeneration: From Invertebrates to Humans

Regenerative through phylogenesis development and regeneration, with special emphasis on the amphibian limb progenitor cells - origin by the reversal of the dedifferentiated state the role of the