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41.
The histones H4 are known as highly conserved proteins. However, in ciliates a high degree of variation was found compared
both to other eukaryotes and between the ciliate species. To date, only H4 histones of species belonging to two distantly
related classes have been investigated. In order to obtain more detailed information on histone H4 variation in ciliates we
undertook a comprehensive sequence analysis of PCR-amplified internal H4 fragments from 12 species belonging to seven out
of the nine currently recognized ciliate classes. In addition, we used PCR primers to amplify longer fragments of H3 and H4
genes including the intergenic region.
The encoded amino acid sequences reveal a high number of differences when compared with those of other eukaryotes and the
ciliate species investigated. Furthermore, in some species H4 gene variants were detected, which result in amino acid differences.
The greatest number of substitutions and insertions found was in the amino terminal region of the H4 histones. However, all
sequences possess a conserved region corresponding to those of all other eukaryotic H4 histones.
The histone gene variations were used to reconstruct phylogenetic relationships. The tree from our data matches perfectly
with the ribosomal RNA data: The heterotrichs, which were considered as a late branching lineage, diverge at the base of the
ciliate tree and groups formerly thought to represent ancestral lineages now appear as highly derived ciliates.
Received: 4 April 1997 / Accepted: 1 August 1997 相似文献
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Antje Repenning Daniela Happel Caroline Bouchard Marion Meixner Yesim VerelYilmaz Hartmann Raifer Lena Holembowski Eberhard Krause Elisabeth Kremmer Regina Feederle Corinna U Keber Michael Lohoff Emily P Slater Detlef K Bartsch UtaMaria Bauer 《The EMBO journal》2021,40(13)
The p14ARF protein is a well‐known regulator of p53‐dependent and p53‐independent tumor‐suppressive activities. In unstressed cells, p14ARF is predominantly sequestered in the nucleoli, bound to its nucleolar interaction partner NPM. Upon genotoxic stress, p14ARF undergoes an immediate redistribution to the nucleo‐ and cytoplasm, where it promotes activation of cell cycle arrest and apoptosis. Here, we identify p14ARF as a novel interaction partner and substrate of PRMT1 (protein arginine methyltransferase 1). PRMT1 methylates several arginine residues in the C‐terminal nuclear/nucleolar localization sequence (NLS/NoLS) of p14ARF. In the absence of cellular stress, these arginines are crucial for nucleolar localization of p14ARF. Genotoxic stress causes augmented interaction between PRMT1 and p14ARF, accompanied by arginine methylation of p14ARF. PRMT1‐dependent NLS/NoLS methylation promotes the release of p14ARF from NPM and nucleolar sequestration, subsequently leading to p53‐independent apoptosis. This PRMT1‐p14ARF cooperation is cancer‐relevant and indicative for PDAC (pancreatic ductal adenocarcinoma) prognosis and chemotherapy response of pancreatic tumor cells. Our data reveal that PRMT1‐mediated arginine methylation is an important trigger for p14ARF’s stress‐induced tumor‐suppressive function. 相似文献
45.
Synergistic Impact of Solvent and Polymer Additives on the Film Formation of Small Molecule Blend Films for Bulk Heterojunction Solar Cells
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Caitlin McDowell Maged Abdelsamie Kui Zhao Detlef‐M. Smilgies Guillermo C. Bazan Aram Amassian 《Liver Transplantation》2015,5(18)
The addition of polystyrene (PS), a typical insulator, is empirically shown to increase the power conversion efficiencies (PCEs) of a solution‐deposited bulk heterojunction (BHJ) molecular blend film used in solar cell fabrication: p‐DTS(FBTTh2)2/PC71BM. The performance is further improved by small quantities of diiodooctane (DIO), an established solvent additive. In this study, how the addition of PS and DIO affects the film formation of this bulk heterojunction blend film are probed via in situ monitoring of absorbance, thickness, and crystallinity. PS and DIO additives are shown to promote donor crystallite formation on different time scales and through different mechanisms. PS‐containing films retain chlorobenzene solvent, extending evaporation time and promoting phase separation earlier in the casting process. This extended time is insufficient to attain the morphology for optimal PCE results before the film sets. Here is where the presence of DIO comes into play: its low vapor pressure further extends the time scale of film evolution and allows for crystalline rearrangement of the donor phase long after casting, ultimately leading to the best BHJ organization. 相似文献
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J?rg Hagmann Claude Becker Jonas Müller Oliver Stegle Rhonda C. Meyer George Wang Korbinian Schneeberger Joffrey Fitz Thomas Altmann Joy Bergelson Karsten Borgwardt Detlef Weigel 《PLoS genetics》2015,11(1)
There has been much excitement about the possibility that exposure to specific environments can induce an ecological memory in the form of whole-sale, genome-wide epigenetic changes that are maintained over many generations. In the model plant Arabidopsis thaliana, numerous heritable DNA methylation differences have been identified in greenhouse-grown isogenic lines, but it remains unknown how natural, highly variable environments affect the rate and spectrum of such changes. Here we present detailed methylome analyses in a geographically dispersed A. thaliana population that constitutes a collection of near-isogenic lines, diverged for at least a century from a common ancestor. Methylome variation largely reflected genetic distance, and was in many aspects similar to that of lines raised in uniform conditions. Thus, even when plants are grown in varying and diverse natural sites, genome-wide epigenetic variation accumulates mostly in a clock-like manner, and epigenetic divergence thus parallels the pattern of genome-wide DNA sequence divergence. 相似文献
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Rebekka Sontowski Detlef Bernhard Christoph Bleidorn Martin Schlegel Michael Gerth 《Ecology and evolution》2015,5(19):4345-4353
Wolbachia (Alphaproteobacteria) is an inherited endosymbiont of arthropods and filarial nematodes and was reported to be widespread across insect taxa. While Wolbachia's effects on host biology are not understood from most of these hosts, known Wolbachia‐induced phenotypes cover a spectrum from obligate beneficial mutualism to reproductive manipulations and pathogenicity. Interestingly, data on Wolbachia within the most species‐rich order of arthropods, the Coleoptera (beetles), are scarce. Therefore, we screened 128 species from seven beetle families (Buprestidae, Hydraenidae, Dytiscidae, Hydrophilidae, Gyrinidae, Haliplidae, and Noteridae) for the presence of Wolbachia. Our data show that, contrary to previous estimations, Wolbachia frequencies in beetles (31% overall) are comparable to the ones in other insects. In addition, we used Wolbachia MLST data and host phylogeny to explore the evolutionary history of Wolbachia strains from Hydraenidae, an aquatic lineage of beetles. Our data suggest that Wolbachia from Hydraenidae might be largely host genus specific and that Wolbachia strain phylogeny is not independent to that of its hosts. As this contrasts with most terrestrial Wolbachia–arthropod systems, one potential conclusion is that aquatic lifestyle of hosts may result in Wolbachia distribution patterns distinct from those of terrestrial hosts. Our data thus provide both insights into Wolbachia distribution among beetles in general and a first glimpse of Wolbachia distribution patterns among aquatic host lineages. 相似文献
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DNA cleavage is a biochemical hallmark of apoptosis. In humans, apoptotic DNA cleavage is executed by DNA fragmentation factor (DFF) 40. In proliferating cells DFF40 is expressed in the presence of its chaperone and inhibitor DFF45, which results in the formation of the DFF complex. Here, we present a systematic analysis of the nuclear import of the DFF complex. Our in vitro experiments demonstrate that the importin alpha/beta-heterodimer mediates the translocation of the DFF complex from the cytoplasm to the nucleus. Both DFF subunits interact directly with the importin alpha/beta-heterodimer. However, importin alpha/beta binds more tightly to the DFF complex compared with the individual subunits. Additionally, the isolated C-terminal regions of both DFF subunits together bind importin alpha/beta more strongly than the individual C termini. Our results from in vivo studies reveal that the C-terminal regions of both DFF subunits harbor nuclear localization signals. Furthermore, nuclear import of the DFF complex requires the C-terminal regions of both subunits. In more detail, one basic cluster in the C-terminal region of each subunit, DFF40 (RLKRK) and DFF45 (KRAR), is essential for nuclear accumulation of the DFF complex. Based on these findings two alternative models for the interaction of importin alpha/beta with the DFF complex are presented. 相似文献
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