title: Reconstruction of rat retinal progenitor cell lineages in vitro reveals a surprising degree of stochasticity in cell fate decisions.
abstract: In vivo cell lineage-tracing studies in the vertebrate retina have revealed that the sizes and cellular compositions of retinal clones are highly variable. It has been challenging to ascertain whether this variability reflects distinct but reproducible lineages among many different retinal progenitor cells (RPCs) or is the product of stochastic fate decisions operating within a population of more equivalent RPCs. To begin to distinguish these possibilities, we developed a method for long-term videomicroscopy to follow the lineages of rat perinatal RPCs cultured at clonal density. In such cultures, cell-cell interactions between two different clones are eliminated and the extracellular environment is kept constant, allowing us to study the cell-intrinsic potential of a given RPC. Quantitative analysis of the reconstructed lineages showed that the mode of division of RPCs is strikingly consistent with a simple stochastic pattern of behavior in which the decision to multiply or differentiate is set by fixed probabilities. The variability seen in the composition and order of cell type genesis within clones is well described by assuming that each of the four different retinal cell types generated at this stage is chosen stochastically by differentiating neurons, with relative probabilities of each type set by their abundance in the mature retina. Although a few of the many possible combinations of cell types within clones occur at frequencies that are incompatible with a fully stochastic model, our results support the notion that stochasticity has a major role during retinal development and therefore possibly in other parts of the central nervous system.
authors.affiliation: Cellular Neurobiology Research Unit, Institut de recherches cliniques de Montréal, Montréal, QC H2W 1R7, Canada.
authors.forename: Francisco L A F
authors.initials: FL
authors.lastname: Gomes
authors.forename: Gen
authors.initials: G
authors.lastname: Zhang
authors.forename: Felix
authors.initials: F
authors.lastname: Carbonell
authors.forename: José A
authors.initials: JA
authors.lastname: Correa
authors.forename: William A
authors.initials: WA
authors.lastname: Harris
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Simons
authors.forename: Michel
authors.initials: M
authors.lastname: Cayouette
mesh_terms: D000818:Animals; D002452:Cell Count; D002453:Cell Cycle; D002454:Cell Differentiation; D002455:Cell Division; D019070:Cell Lineage; D002478:Cells, Cultured; D002999:Clone Cells / Q000166:cytology / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D060850:LIM-Homeodomain Proteins; D018715:Microscopy, Video; D008954:Models, Biological; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins / Q000378:metabolism; D012160:Retina / Q000166:cytology* / Q000196:embryology* / Q000378:metabolism; D013269:Stochastic Processes; D059008:Time-Lapse Imaging; D014157:Transcription Factors
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605733:Pax6 protein, rat; D012097:Repressor Proteins; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1