title: The genetic network of prototypic planarian eye regeneration is Pax6 independent.
abstract: We report the presence of two Pax6-related genes, Pax6A and Pax6B, which are highly conserved in two planarian species Dugesia japonica and Girardia tigrina (Platyhelminthes, Tricladida). Pax6A is more similar to other Pax6 proteins than Pax6B, which is the most divergent Pax6 described so far. The planarian Pax6 homologs do not show any clear orthology to the Drosophila duplicated Pax6 genes, eyeless and twin of eyeless, which suggests an independent Pax6 duplication in a triclad or platyhelminth ancestor. Pax6A is expressed in the central nervous system of intact planarians, labeling a subset of cells of both cephalic ganglia and nerve cords, and is activated during cephalic regeneration. Pax6B follows a similar pattern, but shows a lower level of expression. Pax6A and Pax6B transcripts are detected in visual cells only at the ultrastructural level, probably because a limited amount of transcripts is present in these cells. Inactivation of both Pax6A and Pax6B by RNA-mediated gene interference (RNAi) inhibits neither eye regeneration nor eye maintenance, suggesting that the genetic network that controls this process is not triggered by Pax6 in planarians.
authors.affiliation: Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Pineda
authors.forename: Leonardo
authors.initials: L
authors.lastname: Rossi
authors.forename: Renata
authors.initials: R
authors.lastname: Batistoni
authors.forename: Alessandra
authors.initials: A
authors.lastname: Salvetti
authors.forename: Maria
authors.initials: M
authors.lastname: Marsal
authors.forename: Vittorio
authors.initials: V
authors.lastname: Gremigni
authors.forename: Alessandra
authors.initials: A
authors.lastname: Falleni
authors.forename: Javier
authors.initials: J
authors.lastname: Gonzalez-Linares
authors.forename: Paolo
authors.initials: P
authors.lastname: Deri
authors.forename: Emili
authors.initials: E
authors.lastname: Saló
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005123:Eye; D005136:Eye Proteins; D005786:Gene Expression Regulation / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D010802:Phylogeny; D010932:Planarians / Q000235:genetics* / Q000502:physiology; D012038:Regeneration / Q000235:genetics; D012097:Repressor Proteins; D016415:Sequence Alignment
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins