title: RNAi-mediated silencing of the Arabidopsis thaliana ULCS1 gene, encoding a WDR protein, results in cell wall modification impairment and plant infertility.
abstract: Ubiquitin mediated protein degradation constitutes one of the most complex post translational gene regulation mechanisms in eukaryotes. This fine-tuned proteolytic machinery is based on a vast number of E3 ubiquitin ligase complexes that mark target proteins with ubiquitin. The specificity is accomplished by a number of adaptor proteins that contain functional binding domains, including the WD40 repeat motif (WDRs). To date, only few of these proteins have been identified in plants. An RNAi mediated silencing approach was used here to functionally characterize the Arabidopsis thaliana ULCS1 gene, which encodes for a small molecular weight WDR protein. AtULCS1 interacts with the E3Cullin Ring Ligase subunit DDB1a, regulating most likely the degradation of specific proteins involved in the manifestation of diverse developmental events. Silencing of AtULCS1 results in sterile plants with pleiotropic phenotypes. Detailed analysis revealed that infertility is the outcome of anther indehiscence, which in turn is due to the impairment of the plants to accomplish secondary wall modifications. Furthermore, IREGULAR XYLEM gene expression and lignification is diminished in anther endothecium and the stem vascular tissue of the silenced plants. These data underline the importance of AtULCS1 in plant development and reproduction.
authors.affiliation: University of Athens, Faculty of Biology, Department of Botany, 15784 Athens, Greece. Electronic address: debthem@hotmail.com.
authors.forename: Despoina
authors.initials: D
authors.lastname: Beris
authors.affiliation: University of Athens, Faculty of Biology, Department of Botany, 15784 Athens, Greece. Electronic address: gkapolas@yahoo.gr.
authors.forename: Georgios
authors.initials: G
authors.lastname: Kapolas
authors.affiliation: University of Athens, Faculty of Biology, Department of Botany, 15784 Athens, Greece. Electronic address: plivanos@biol.uoa.gr.
authors.forename: Pantelis
authors.initials: P
authors.lastname: Livanos
authors.affiliation: University of Athens, Faculty of Biology, Department of Botany, 15784 Athens, Greece. Electronic address: aroussis@biol.uoa.gr.
authors.forename: Andreas
authors.initials: A
authors.lastname: Roussis
authors.affiliation: Agricultural University of Athens, Department of Agricultural Biotechnology, Iera Odos 75, 11855 Athens, Greece. Electronic address: bmbi2mid@aua.gr.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Milioni
authors.affiliation: University of Athens, Faculty of Biology, Department of Botany, 15784 Athens, Greece. Electronic address: kharalamp@biol.uoa.gr.
authors.forename: Kosmas
authors.initials: K
authors.lastname: Haralampidis
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism*; D019295:Computational Biology; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017343:Genes, Plant; D005966:Glucuronidase / Q000378:metabolism; D008031:Lignin / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D051479:Plant Infertility; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics; D012639:Seeds / Q000033:anatomy & histology / Q000196:embryology; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C517426:DDB1a protein, Arabidopsis; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; C000612387:ULCS1 protein, Arabidopsis; D008031:Lignin; D005966:Glucuronidase
keywords: Arabidopsis; CRL complex; Cell wall; Infertility; Lignification; Ubiquitination; WD40 motif; WDR protein