Chromatin assembly factor CAF-1 is required for cellular differentiation during plant development.
Chromatin assembly factor CAF-1 facilitates the formation of nucleosomes on newly replicated DNA in vitro. However, the role of CAF-1 in development is poorly understood because mutants are not available in most multicellular model organisms. Biochemical evidence suggests that FASCIATA1, FASCIATA2 and MSI1 form CAF-1 in Arabidopsis thaliana. Because fasciata mutants are viable, CAF-1 is not essential for cell division in plants. Arabidopsis CAF-1 mutants have defects in shoot apical meristems; in addition, CAF-1 is required to establish seedling architecture, leaf size and trichome differentiation. CAF-1 is needed to restrict branching of trichomes on rosette leaves. Increased trichome branching in CAF-1 mutants is not strictly correlated with increased nuclear DNA content. In addition, fas2 glabra3 double mutants show an additive genetic interaction, demonstrating that CAF-1 acts genetically parallel to the GLABRA3-containing, endoreduplication-coupled trichome branching pathway. However, CAF-1 is often needed to restrict endoreduplication, because seedlings of most CAF-1 mutants have increased ploidy. Notably, in the Landsberg erecta background, loss of CAF-1 does not affect ploidy, demonstrating that loss of CAF-1 can be compensated in some Arabidopsis accessions. These results reveal that the functions of FAS1, FAS2 and MSI1 are not restricted to meristems, but are also needed to control genome replication at multiple steps of development.
Exner
Vivien
V
Institute of Plant Sciences and Basel-Zurich Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland.
Taranto
Patti
P
Schönrock
Nicole
N
Gruissem
Wilhelm
W
Hennig
Lars
L
D000818:Animals; D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D056504:Chromatin Assembly Factor-1; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006801:Humans; D018546:Hypocotyl / Q000254:growth & development; D018519:Meristem / Q000033:anatomy & histology / Q000254:growth & development; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development; D030821:Plants, Genetically Modified; D011003:Ploidies; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000033:anatomy & histology / Q000254:growth & development
D029681:Arabidopsis Proteins; C533593:CHAF1B protein, human; D056504:Chromatin Assembly Factor-1; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C422044:FAS protein, Arabidopsis; C475821:MSI1 protein, Arabidopsis; D021122:Protein Subunits