title: Telomere dynamics in the lower plant Physcomitrella patens.
abstract: A comparative approach in biology is needed to assess the universality of rules governing this discipline. In plant telomere research, most of the key principles were established based on studies in only single model plant, Arabidopsis thaliana. These principles include the absence of telomere shortening during plant development and the corresponding activity of telomerase in dividing (meristem) plant cells. Here we examine these principles in Physcomitrella patens as a representative of lower plants. To follow telomerase expression, we first characterize the gene coding for the telomerase reverse transcriptase subunit PpTERT in P. patens, for which only incomplete prediction has been available so far. In protonema cultures of P. patens, growing by filament apical cell division, the proportion of apical (dividing) cells was quantified and telomere length, telomerase expression and activity were determined. Our results show telomere stability and demonstrate proportionality of telomerase activity and expression with the number of apical cells. In addition, we analyze telomere maintenance in mre11, rad50, nbs1, ku70 and lig4 mutants of P. patens and compare the impact of these mutations in double-strand-break (DSB) repair pathways with earlier observations in corresponding A. thaliana mutants. Telomere phenotypes are absent and DSB repair kinetics is not affected in P. patens mutants for DSB factors involved in non-homologous end joining (NHEJ). This is compliant with the overall dominance of homologous recombination over NHEJ pathways in the moss, contrary to the inverse situation in flowering plants.
authors.affiliation: Faculty of Science and CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
authors.forename: Miloslava
authors.initials: M
authors.lastname: Fojtová
authors.forename: Eva
authors.initials: E
authors.lastname: Sýkorová
authors.forename: Lucie
authors.initials: L
authors.lastname: Najdekrová
authors.forename: Pavla
authors.initials: P
authors.lastname: Polanská
authors.forename: Dagmar
authors.initials: D
authors.lastname: Zachová
authors.forename: Radka
authors.initials: R
authors.lastname: Vagnerová
authors.forename: Karel J
authors.initials: KJ
authors.lastname: Angelis
authors.forename: Jiří
authors.initials: J
authors.lastname: Fajkus
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D001483:Base Sequence; D019068:Bryopsida / Q000235:genetics* / Q000378:metabolism; D032461:Chromosomes, Plant / Q000235:genetics*; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D018744:DNA, Plant / Q000235:genetics; D059765:Homologous Recombination; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism; D016615:Telomere / Q000235:genetics*; D059505:Telomere Homeostasis / Q000235:genetics*
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D019098:Telomerase