Encontrados 10 documentos, a visualizar página 1 de 1
Rye Bs disclose ancestral sequences in cereal genomes with a potential role in ...
Pereira, H. Sofia; Barão, Augusta; Caperta, A.; Rocha, João; Viegas, Wanda; Delgado, MargaridaResearch Article ; Two sequence families, E3900 and D1100, are amplified on the subtelomeric domain of the long arm of rye B chromosomes, the region that controls its drive mechanism. In this work, polymerase chain reaction (PCR) with a number of primers spanning E3900 shows that the organization and nucleotide sequence of E3900-related portions are present and highly conserved on rye A chromosomes as well as ...
Effects of individual and population parameters on reproductive success in thre...
Vandewoestijne, S.; Róis, A.S.; Caperta, A.; Baguette, M.; Tyteca, D.Research Paper ; Reproductive success (RS) in orchids in general, and in non-rewarding species specifically, is extremely low. RS is pollinator and pollination limited in food deceptive orchids, but this has rarely been studied in sexually deceptive orchid species. Here, we tested the effects of several individual (plant height, inflorescence size, nearest neighbour distance and flower position) and population...
Distribution patterns of phosphorylated Thr 3 and Thr 32 of histone H3 in plant...
Caperta, A.; Rosa, M.; Delgado, M.; Karimi, R.; Demidov, D.; Viegas, Wanda; Houben, A.Cell cycle dependent phosphorylation of conserved N-terminal tail residues of histone H3 has been described in both animal and plant cells. Through cytogenetic approaches using different plant species we show a detailed description of distribution patterns of phosphorylated histone H3 at either threonine 3 or threonine 32 in mitosis and meiosis. In meristematic cells of the large genome species Secale cereale, ...
Transcriptionally active heterochromatin in rye B chromosomes
Carchilan, Mariana; Delgado, Margarida; Ribeiro, Teresa; Nunes, Pedro Costa; Caperta, A.; Morais-Cecílio, L.; Jones, R. Neil; Viegas, WandaB chromosomes (Bs) are dispensable components of the genomes of numerous species. Thus far, there is a lack of evidence for any transcripts of Bs in plants, with the exception of some rDNA sequences. Here, we show that the Giemsa bandingpositive heterochromatic subterminal domain of rye (Secale cereale) Bs undergoes decondensation during interphase. Contrary to the heterochromatic regions of A chromosomes, this...
Relationships between transcription, silver staining and chromatin organization...
Caperta, A.; Neves, Nuno; Viegas, Wanda; Pikaard, Craig S.; Preuss, SashaSummary. The nucleolar organizer regions (NORs) are composed of hundreds of rRNA genes, typically spanning several megabases. Cytologically, NORs include regions that are highly condensed and regions that are decondensed, the latter corresponding to regions at which associated proteins stain intensively with silver (Ag-NORs) and where active rRNA gene transcription is thought to occur. To test the relationship ...
Phosphorilation of histone H3 in plants - a dynamic affair
Houben, Andreas; Demidov, Dmitri; Caperta, A.; Karimi, Raheleh; Agueci, Francesco; Vlasenko, LiudmilaHistones are the main protein components of chromatin: they undergo extensive post-translational modifications, particularly acetylation, methylation, phosphorylation, ubiquitination and ADP-ribosylation which modify the structural/functional properties of chromatin. Posttranslational modifications of the N-terminal tails of the core histones within the nucleosome particle are thought to act as signals from the...
Cochicine-induced polyploidization depends on tubulin polymerization in c-metap...
Caperta, A.; Delgado, M.; Ressurreição, F.; Meister, A.; Jones, R.N.; Viegas, W.; Houben, A.The microtubule cytoskeleton plays a crucial role in the cell cycle and in mitosis. Colchicine is a microtubule-depolymerizing agent that has long been used to induce chromosome individualization in cells arrested at metaphase and also in the induction of polyploid plants. Although attempts have been made to explain the processes and mechanisms underlying polyploidy induction, the role of the cytoskeleton still...
Ribosomal DNA heterochromatin in plants
Neves, N.; Delgado, M.; Silva, M.; Caperta, A.; Morais-Cecílio, L.; Viegas, W.The aim of this review is to integrate earlier results and recent findings to present the current state-of-the art vision concerning the dynamic behavior of the ribosomal DNA (rDNA) fraction in plants. The global organization and behavioral features of rDNA make it a most useful system to analyse the relationship between chromatin topology and gene expression patterns. Correlations between several heterochromat...
Different numbers of rye B chromosomes induce identical compaction changes in d...
Delgado, M.; Caperta, A.; Ribeiro, T.; Viegas, W.; Jones, R.N.; Morais-Cecilio, L.In rye each B chromosome (B) represents 5.5% of the diploid A genome. Rye Bs have several nuclear to whole plant effects although they seem to bear no genes except for the ones that lead to their maintenance within a population. In this context, and considering that rye Bs are enriched in repetitive non-coding regions that build up heterochromatin (het), we investigated the influence of Bs on the organization o...
Genome restructuring in rye affects the expression, organization and dispositio...
Caperta, A.; Neves, Nuno; Morais-Cecílio, L.; Malhó, Rui; Viegas, WandaResearch Article ; The standard rye cultivar ‘Imperial’ and a structural variant carrying an intact 1R chromosome and two telocentric 1R chromosomes (short and long arms) were used to investigate expression patterns of homologous rDNA loci, and the influence of chromosome structural change on their interphase organisation and relative disposition. Sequential silver staining and in situ hybridization with the r...
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