title: DjPum, a homologue of Drosophila Pumilio, is essential to planarian stem cell maintenance.
abstract: As stem cells are rare and difficult to study in vivo in adults, the use of classical models of regeneration to address fundamental aspects of the stem cell biology is emerging. Planarian regeneration, which is based upon totipotent stem cells present in the adult--the so-called neoblasts--provides a unique opportunity to study in vivo the molecular program that defines a stem cell. The choice of a stem cell to self-renew or differentiate involves regulatory molecules that also operate as translational repressors, such as members of PUF proteins. In this study, we identified a homologue of the Drosophila PUF gene Pumilio (DjPum) in the planarian Dugesia japonica, with an expression pattern preferentially restricted to neoblasts. Through RNA interference (RNAi), we demonstrate that gene silencing of DjPum dramatically reduces the number of neoblasts, thus supporting the intriguing hypothesis that stem cell maintenance may be an ancestral function of PUF proteins.
authors.affiliation: Dipartimento di Morfologia Umana e Biologia Applicata, Sezione di Biologia e Genetica, Università di Pisa, Pisa, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Salvetti
authors.forename: Leonardo
authors.initials: L
authors.lastname: Rossi
authors.forename: Annalisa
authors.initials: A
authors.lastname: Lena
authors.forename: Renata
authors.initials: R
authors.lastname: Batistoni
authors.forename: Paolo
authors.initials: P
authors.lastname: Deri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rainaldi
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Locci
authors.forename: Monica
authors.initials: M
authors.lastname: Evangelista
authors.forename: Vittorio
authors.initials: V
authors.lastname: Gremigni
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D029721:Drosophila Proteins / Q000235:genetics*; D005434:Flow Cytometry; D020868:Gene Silencing; D017403:In Situ Hybridization; D020287:In Situ Nick-End Labeling; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010802:Phylogeny; D010932:Planarians / Q000235:genetics* / Q000502:physiology* / Q000648:ultrastructure; D034622:RNA Interference; D016601:RNA-Binding Proteins; D012038:Regeneration / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013234:Stem Cells / Q000378:metabolism / Q000502:physiology*
chemical_list: D017931:DNA Primers; D029721:Drosophila Proteins; D016601:RNA-Binding Proteins; C074333:pum protein, Drosophila