title: AtMMS21, an SMC5/6 complex subunit, is involved in stem cell niche maintenance and DNA damage responses in Arabidopsis roots.
abstract: Plants maintain stem cells in meristems to sustain lifelong growth; these stem cells must have effective DNA damage responses to prevent mutations that can propagate to large parts of the plant. However, the molecular links between stem cell functions and DNA damage responses remain largely unexplored. Here, we report that the small ubiquitin-related modifier E3 ligase AtMMS21 (for methyl methanesulfonate sensitivity gene21) acts to maintain the root stem cell niche by mediating DNA damage responses in Arabidopsis (Arabidopsis thaliana). Mutation of AtMMS21 causes defects in the root stem cell niche during embryogenesis and postembryonic stages. AtMMS21 is essential for the proper expression of stem cell niche-defining transcription factors. Moreover, mms21-1 mutants are hypersensitive to DNA-damaging agents, have a constitutively increased DNA damage response, and have more DNA double-strand breaks (DSBs) in the roots. Also, mms21-1 mutants exhibit spontaneous cell death within the root stem cell niche, and treatment with DSB-inducing agents increases this cell death, suggesting that AtMMS21 is required to prevent DSB-induced stem cell death. We further show that AtMMS21 functions as a subunit of the STRUCTURAL MAINTENANCE OF CHROMOSOMES5/6 complex, an evolutionarily conserved chromosomal ATPase required for DNA repair. These data reveal that AtMMS21 acts in DSB amelioration and stem cell niche maintenance during Arabidopsis root development.
authors: Guangdong Key Laboratory of Biotechnology for Plant Development, College of Life Science, South China Normal University, Guangzhou 510631, China.
authors: Panglian
authors: P
authors: Xu
authors: Dongke
authors: D
authors: Yuan
authors: Ming
authors: M
authors: Liu
authors: Chunxin
authors: C
authors: Li
authors: Yiyang
authors: Y
authors: Liu
authors: Shengchun
authors: S
authors: Zhang
authors: Nan
authors: N
authors: Yao
authors: Chengwei
authors: C
authors: Yang
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000196:embryology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D016923:Cell Death; D002454:Cell Differentiation; D002455:Cell Division; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D008025:Ligases / Q000378:metabolism*; D018519:Meristem / Q000166:cytology / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology* / Q000378:metabolism*; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D055153:Stem Cell Niche; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D021122:Protein Subunits; D014157:Transcription Factors; D008025:Ligases; C555898:MMS21 protein, Arabidopsis