Article

Cell adhesion in Arabidopsis thaliana is mediated by ECTOPICALLY PARTING CELLS 1--a glycosyltransferase (GT64) related to the animal exostosins.

Department of Forest Genetics and Plant Physiology, SLU, 901 83 Umeå, Sweden.
The Plant Journal (Impact Factor: 6.82). 09/2005; 43(3):384-97. DOI: 10.1111/j.1365-313X.2005.02455.x
Source: PubMed

ABSTRACT Despite the fact that several hundred glycosyltransferases have been identified from sequencing of plant genomes, the biological functions of only a handful have been established to date. A Poplar glycosyltransferase 64 (GT64) family member that is differentially expressed during the cell division and elongation phases of cambial growth was identified from previously generated transcript profiling of cambium tissues. The predicted Poplar GT64 protein has a closely related Arabidopsis homolog ECTOPICALLY PARTING CELLS (EPC1). Mutation of the EPC1 gene, one of three Arabidopsis GT64 family members, results in plants with a dramatically reduced growth habit, defects in vascular formation and reduced cell-cell adhesion properties in hypocotyl and cotyledon tissues. Secondary growth is enhanced in epc1 hypocotyl tissues and it is proposed that this results from the abnormal cell-cell adhesion within the cortical parenchyma cell layers. Loss of cell-cell contacts within cotyledon and leaf tissues is also proposed to account for vascular patterning defects and the fragile nature of epc1 tissues. The EPC1 protein thus plays a critical role during plant development in maintaining the integrity of organs via cell-cell adhesion, thereby providing mechanical strength and facilitating the movement of metabolites throughout the plant.

0 Followers
 · 
138 Views
  • Source
    • "We measured the height of epidermal cell contact zones and found that they are less uniform in height in dek1-4 than in WT seedlings (supplementary material Fig. S7). Consistent with a defect in epidermal cell adhesion (Singh et al., 2005), we also observed examples of cell separation in the cotyledons of 35S:amiRDEK1 lines and the abnormal accumulation of callose at epidermal cell boundaries in Fig. 2. dek1-4 mutants show reduced expression of differentiationpromoting HD-ZIP IV TF-encoding genes. (A,B) Ten-day-old Col-0 (A) and dek1-4 (B) seedlings. "
    [Show abstract] [Hide abstract]
    ABSTRACT: During plant epidermal development, many cell types are generated from protodermal cells, a process requiring complex coordination of cell division, growth, endoreduplication and the acquisition of differentiated cellular morphologies. Here we show that the Arabidopsis phytocalpain DEFECTIVE KERNEL 1 (DEK1) promotes the differentiated epidermal state. Plants with reduced DEK1 activity produce cotyledon epidermis with protodermal characteristics, despite showing normal growth and endoreduplication. Furthermore, in non-embryonic tissues (true leaves, sepals), DEK1 is required for epidermis differentiation maintenance. We show that the HD-ZIP IV family of epidermis-specific differentiation-promoting transcription factors are key, albeit indirect, targets of DEK1 activity. We propose a model in which DEK1 influences HD-ZIP IV gene expression, and thus epidermis differentiation, by promoting cell adhesion and communication in the epidermis.
    Development 05/2015; DOI:10.1242/dev.122325 · 6.27 Impact Factor
  • Source
    • "Inference (Chini et al., 2007; Thines et al., 2007) AT3G55830 0.2 ECTOPICALLY PARTING CELLS (EPC1) Phenotype (Singh et al., 2005) AT1G75820 À10.6 CLAVATA 1 (CLV1) Phenotype (Brand et al., 2000; Clark et al., 1993; Clark et al., 1997; Ogawa et al., 2008; Schoof et al., 2000) AT1G13950 6.7 EUKARYOTIC ELONGATION FACTOR 5A-1 (ELF5A-1) Inference (Feng et al., 2007) "
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite the independent evolution of multicellularity in plants and animals, the basic organization of their stem cell niches is remarkably similar. Here, we report the genome-wide regulatory potential of WUSCHEL, the key transcription factor for stem cell maintenance in the shoot apical meristem of the reference plant Arabidopsis thaliana. WUSCHEL acts by directly binding to at least two distinct DNA motifs in more than 100 target promoters and preferentially affects the expression of genes with roles in hormone signaling, metabolism, and development. Striking examples are the direct transcriptional repression of CLAVATA1, which is part of a negative feedback regulation of WUSCHEL, and the immediate regulation of transcriptional repressors of the TOPLESS family, which are involved in auxin signaling. Our results shed light on the complex transcriptional programs required for the maintenance of a dynamic and essential stem cell niche.
    Developmental Cell 05/2010; 18(5):849-61. DOI:10.1016/j.devcel.2010.03.012 · 10.37 Impact Factor
  • Source
    • "Border-like cells organized in files Madson et al. (2003) Cellulose kor1 At5g49720 Border-like cells organized in files Nicol et al. (1998) rsw1 At4g32410 Reduced border-like cell formation at 30°C Arioli et al. (1998) Pectin qua1-1 At3g25140 Isolated border-like cells and thick mucilage Bouton et al. (2002) qua2-1 At1g78240 Isolated border-like cells and sometimes thick mucilage Mouille et al. (2007) arad1-1 At2g35100 Border-like cells organized in files Harholt et al. (2006) Undefined function epc1-1 At3g55830 Border-like cells organized in files Singh et al. (2005) Cell Attachment in Root Border-Like Cells Plant Physiol. Vol. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Border-like cells are released by Arabidopsis (Arabidopsis thaliana) root tips as organized layers of several cells that remain attached to each other rather than completely detached from each other, as is usually observed in border cells of many species. Unlike border cells, cell attachment between border-like cells is maintained after their release into the external environment. To investigate the role of cell wall polysaccharides in the attachment and organization of border-like cells, we have examined their release in several well-characterized mutants defective in the biosynthesis of xyloglucan, cellulose, or pectin. Our data show that among all mutants examined, only quasimodo mutants (qua1-1 and qua2-1), which have been characterized as producing less homogalacturonan, had an altered border-like cell phenotype as compared with the wild type. Border-like cells in both lines were released as isolated cells separated from each other, with the phenotype being much more pronounced in qua1-1 than in qua2-1. Further analysis of border-like cells in the qua1-1 mutant using immunocytochemistry and a set of anti-cell wall polysaccharide antibodies showed that the loss of the wild-type phenotype was accompanied by (1) a reduction in homogalacturonan-JIM5 epitope in the cell wall of border-like cells, confirmed by Fourier transform infrared microspectrometry, and (2) the secretion of an abundant mucilage that is enriched in xylogalacturonan and arabinogalactan-protein epitopes, in which the cells are trapped in the vicinity of the root tip.
    Plant physiology 06/2009; 150(3):1411-21. DOI:10.1104/pp.109.136382 · 7.39 Impact Factor
Show more