title: Pax6 expression during retinogenesis in sharks: comparison with markers of cell proliferation and neuronal differentiation.
abstract: Pax6 is a highly conserved transcription factor that appears involved in the entire process of retinogenesis, including maintenance of proliferation of retinal progenitors and differentiation of particular neuron fates. To gain insight into the retinogenesis in fish, we study the dynamics of Pax6 expression in the developing and mature retina of two sharks that inhabit in particular environments, and compare it with the dynamics of a marker of cell proliferation (proliferating cell nuclear antigen, PCNA) and markers of neuronal differentiation, such as glutamic acid decarboxylase (GAD), calretinin (CR), tyrosine-hydroxylase, and serotonin (5-HT). Our results reveal that Pax6 is expressed in PCNA-immunoreactive cells within the nonlayered retina, suggesting a role for Pax6 in proliferating progenitors. Pax6 expression decays as development proceeds and eventually remains in some postmitotic cells, which points to additional roles of Pax6 following neurogenesis. Double immunofluorescence reveals Pax6/CR colocalization in the ganglion cell layer, Pax6/5-HT in the inner part of the inner nuclear layer (INLi), and Pax6/GAD in the INLi and horizontal cell layer. Our results suggest that Pax6 may contribute to neuron diversification in the neural retina.
authors.affiliation: Department of Cell Biology and Ecology, University of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Ferreiro-Galve
authors.forename: Isabel
authors.initials: I
authors.lastname: Rodríguez-Moldes
authors.forename: Eva
authors.initials: E
authors.lastname: Candal
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D002454:Cell Differentiation; D049109:Cell Proliferation; D005136:Eye Proteins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D018398:Homeodomain Proteins / Q000378:metabolism*; D017403:In Situ Hybridization; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D012160:Retina / Q000254:growth & development / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins