title: Planarian regeneration: achievements and future directions after 20 years of research.
abstract: Planarians can undergo dramatic changes in body size and regenerate their entire body plan from small pieces after cutting. This remarkable morphological plasticity has made them an excellent model in which to analyze phenomena such as morphogenesis, restoration of pattern and polarity, control of tissue proportions and tissue homeostasis. They have a unique population of pluripotent stem cells in the adult that can give rise to all differentiated cell types, including the germ cells. These cellular characteristics provide an excellent opportunity to study the mechanisms involved in the maintenance and differentiation of cell populations in intact and regenerating animals. Until recently, the planarian model system lacked opportunities for genetic analysis; however, this handicap was overcome in the last decade through the development of new molecular methods which have been successfully applied to planarians. These techniques have allowed analysis of the temporal and spatial expression of genes, as well as interference with gene function, generating the first phenotypes by loss or gain of function. Finally, the sequencing of the planarian genome has provided the essential tools for an in-depth analysis of the genomic regulation of this model system. In this review, we provide an overview of planarians as a model system for research into development and regeneration and describe new lines of investigation in this area.
authors.affiliation: Departament de Genètica, Facultat de Biologia and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Catalunya, Spain. esalo@ub.edu
authors.forename: Emili
authors.initials: E
authors.lastname: Saló
authors.forename: Josep F
authors.initials: JF
authors.lastname: Abril
authors.forename: Teresa
authors.initials: T
authors.lastname: Adell
authors.forename: Francesc
authors.initials: F
authors.lastname: Cebrià
authors.forename: Kay
authors.initials: K
authors.lastname: Eckelt
authors.forename: Enrique
authors.initials: E
authors.lastname: Fernandez-Taboada
authors.forename: Mette
authors.initials: M
authors.lastname: Handberg-Thorsager
authors.forename: Marta
authors.initials: M
authors.lastname: Iglesias
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Molina
authors.forename: Gustavo
authors.initials: G
authors.lastname: Rodríguez-Esteban
mesh_terms: D000818:Animals; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics; D008854:Microscopy, Electron; D008954:Models, Biological; D009024:Morphogenesis / Q000235:genetics / Q000502:physiology*; D010932:Planarians / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D012038:Regeneration / Q000235:genetics / Q000502:physiology*; D012106:Research / Q000639:trends; D012107:Research Design
chemical_list: D018398:Homeodomain Proteins