title: Distinct cell-autonomous functions of RETINOBLASTOMA-RELATED in Arabidopsis stem cells revealed by the Brother of Brainbow clonal analysis system.
abstract: Mutations that cause lethality in the gametophyte phase pose a major challenge for studying postfertilization gene function. When both male and female haploid cells require a functional gene copy, null alleles cause developmental arrest before the formation of the zygote, precluding further investigation. The Arabidopsis thaliana Rb homolog RETINOBLASTOMA-RELATED (RBR) has an important function in the stem cell niche, but its requirement in both male and female gametophytes has prevented full loss-of-function studies. To circumvent this obstacle, we designed a clonal deletion system named BOB (Brother of Brainbow) in which null mutant sectors marked by double fluorescence are generated in a fully complemented wild-type background. In this system, both copies of a complementing RBR transgene are eliminated by tissue-specific and inducible CRE expression, and homozygous mutant clones can be distinguished visually. Since mutant sectors can be produced in a homozygous, rather than a heterozygous, background, this system facilitates clonal deletion analysis not only for gametophytic lethal alleles but also for any type of mutation. Using the BOB system, we show that RBR has unique cell-autonomous functions in different cell types within the root stem cell niche.
authors: Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors: Guy
authors: G
authors: Wachsman
authors: Renze
authors: R
authors: Heidstra
authors: Ben
authors: B
authors: Scheres
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000166:cytology* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test / Q000379:methods*; D006801:Humans; D056771:Ovule / Q000166:cytology / Q000502:physiology; D018517:Plant Roots / Q000166:cytology; D030821:Plants, Genetically Modified; D011058:Pollen / Q000166:cytology / Q000502:physiology; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D055153:Stem Cell Niche; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: D029681:Arabidopsis Proteins; C487568:RBR1 protein, Arabidopsis; D011993:Recombinant Fusion Proteins