RESUMO
Temperature is a major determinant of plant growth, development and success. Understanding how plants respond to temperature is particularly relevant in a warming climate. Plant immune responses are often suppressed above species-specific critical temperatures. This is also true for intraspecific hybrids of Arabidopsis thaliana that express hybrid necrosis due to inappropriate activation of the immune system caused by epistatic interactions between alleles from different genomes. The relationship between temperature and defence is unclear, largely due to a lack of studies that assess immune activation over a wide range of temperatures. To test whether the temperature-based suppression of ectopic immune activation in hybrids exhibits a linear or non-linear relationship, we characterised the molecular and morphological phenotypes of two different necrotic A. thaliana hybrids over a range of ecologically relevant temperatures. We found both linear and non-linear responses for expression of immunity markers and for morphological defects depending on the underlying genetic cause. This suggests that the influence of temperature on the trade-off between immunity and growth depends on the specific defence components involved.
Assuntos
Arabidopsis/genética , Cruzamentos Genéticos , Doenças das Plantas/genética , Arabidopsis/imunologia , Regulação da Expressão Gênica de Plantas , Hibridização Genética , Doenças das Plantas/imunologia , Fenômenos Fisiológicos Vegetais , Temperatura , TranscriptomaRESUMO
We have purified a complex from Saccharomyces cerevisiae containing the spindle components Ndc80p, Nuf2p, Spc25p, and Spc24p. Temperature-sensitive mutants in NDC80, SPC25, and SPC24 show defects in chromosome segregation. In spc24-1 cells, green fluorescence protein (GFP)-labeled centromeres fail to split during spindle elongation, and in addition some centromeres may detach from the spindle. Chromatin immunoprecipitation assays show an association of all four components of the complex with the yeast centromere. Homologues of Ndc80p, Nuf2p, and Spc24p were found in Schizosaccharomyces pombe and GFP tagging showed they were located at the centromere. A human homologue of Nuf2p was identified in the expressed sequence tag database. Immunofluorescent staining with anti-human Nuf2p and with anti-HEC, the human homologue of Ndc80p, showed that both proteins are at the centromeres of mitotic HeLa cells. Thus the Ndc80p complex contains centromere-associated components conserved between yeasts and vertebrates.
Assuntos
Proteínas de Ciclo Celular , Centrômero/fisiologia , Cromossomos Fúngicos/fisiologia , Proteínas Fúngicas/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/genética , Sequência de Aminoácidos , Animais , Caenorhabditis elegans , Centrômero/genética , Cromossomos Fúngicos/genética , Sequência Conservada , Proteínas Fúngicas/análise , Proteínas Fúngicas/genética , Proteínas de Fluorescência Verde , Células HeLa , Humanos , Cinetocoros , Proteínas Luminescentes/análise , Proteínas Luminescentes/genética , Camundongos , Microscopia Imunoeletrônica , Proteínas Associadas aos Microtúbulos/análise , Proteínas Associadas aos Microtúbulos/genética , Mitose , Dados de Sequência Molecular , Proteínas Nucleares/análise , Proteínas Nucleares/genética , Proteínas Recombinantes de Fusão/análise , Saccharomyces cerevisiae/ultraestrutura , Schizosaccharomyces/ultraestrutura , Proteínas de Schizosaccharomyces pombe/análise , Proteínas de Schizosaccharomyces pombe/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Fuso Acromático/genética , Fuso Acromático/ultraestruturaRESUMO
The complete genome sequence of the flowering plant Arabidopsis thaliana has been determined. New insights have come from comparisons between this sequence and genome sequences of other species, including those of cyanobacteria, yeast, worms and flies.
Assuntos
Arabidopsis/genética , Genoma de Planta , Proteínas de Membrana/genética , Animais , Receptores NotchRESUMO
A highly enriched spindle pole preparation was prepared from budding yeast and fractionated by SDS gel electrophoresis. Forty-five of the gel bands that appeared enriched in this fraction were analyzed by high-mass accuracy matrix-assisted laser desorption/ ionization (MALDI) peptide mass mapping combined with sequence database searching. This identified twelve of the known spindle pole components and an additional eleven gene products that had not previously been localized to the spindle pole. Immunoelectron microscopy localized eight of these components to different parts of the spindle. One of the gene products, Ndc80p, shows homology to human HEC protein (Chen, Y., D.J. Riley, P-L. Chen, and W-H. Lee. 1997. Mol. Cell Biol. 17:6049-6056) and temperature-sensitive mutants show defects in chromosome segregation. This is the first report of the identification of the components of a large cellular organelle by MALDI peptide mapping alone.