75 research outputs found

    A Complex Containing the CPSF73 Endonuclease and Other Polyadenylation Factors Associates with U7 snRNP and Is Recruited to Histone Pre-mRNA for 3'-End Processing

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    Animal replication-dependent histone pre-mRNAs are processed at the 3′ end by endonucleolytic cleavage that is not followed by polyadenylation. The cleavage reaction is catalyzed by CPSF73 and depends on the U7 snRNP and its integral component, Lsm11. A critical role is also played by the 220-kDa protein FLASH, which interacts with Lsm11. Here we demonstrate that the N-terminal regions of these two proteins form a platform that tightly interacts with a unique combination of polyadenylation factors: symplekin, CstF64, and all CPSF subunits, including the endonuclease CPSF73. The interaction is inhibited by alterations in each component of the FLASH/Lsm11 complex, including point mutations in FLASH that are detrimental for processing. The same polyadenylation factors are associated with the endogenous U7 snRNP and are recruited in a U7-dependent manner to histone pre-mRNA. Collectively, our studies identify the molecular mechanism that recruits the CPSF73 endonuclease to histone pre-mRNAs, reveal an unexpected complexity of the U7 snRNP, and suggest that in animal cells polyadenylation factors assemble into two alternative complexes—one specifically crafted to generate polyadenylated mRNAs and the other to generate nonpolyadenylated histone mRNAs that end with the stem-loop

    Comprehensive Analysis of the Palindromic Motif TCTCGCGAGA: A Regulatory Element of the HNRNPK Promoter

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    Definitive identification of promoters, their cis-regulatory motifs, and their trans-acting proteins requires experimental analysis. To define the HNRNPK promoter and its cognate DNA–protein interactions, we performed a comprehensive study combining experimental approaches, including luciferase reporter gene assays, chromatin immunoprecipitations (ChIP), electrophoretic mobility shift assays (EMSA), and mass spectrometry (MS). We discovered that out of the four potential HNRNPK promoters tested, the one containing the palindromic motif TCTCGCGAGA exhibited the highest activity in a reporter system assay. Although further EMSA and MS analyses, performed to uncover the identity of the palindrome-binding transcription factor, did identify a complex of DNA-binding proteins, neither method unambiguously identified the pertinent direct trans-acting protein(s). ChIP revealed similar chromatin states at the promoters with the palindromic motif and at housekeeping gene promoters. A ChIP survey showed significantly higher recruitment of PARP1, a protein identified by MS as ubiquitously attached to DNA probes, within heterochromatin sites. Computational analyses indicated that this palindrome displays features that mark nucleosome boundaries, causing the surrounding DNA landscape to be constitutively open. Our strategy of diverse approaches facilitated the direct characterization of various molecular properties of HNRNPK promoter bearing the palindromic motif TCTCGCGAGA, despite the obstacles that accompany in vitro methods

    Comparative kinome analysis to identify putative colon tumor biomarkers

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    Kinase domains are the type of protein domain most commonly found in genes associated with tumorigenesis. Because of this, the human kinome (the protein kinase component of the genome) represents a promising source of cancer biomarkers and potential targets for novel anti-cancer therapies. Alterations in the human colon kinome during the progression from normal colon (NC) through adenoma (AD) to adenocarcinoma (AC) were investigated using integrated transcriptomic and proteomic datasets. Two hundred thirty kinase genes and 42 kinase proteins showed differential expression patterns (fold change ≥ 1.5) in at least one tissue pair-wise comparison (AD vs. NC, AC vs. NC, and/or AC vs. AD). Kinases that exhibited similar trends in expression at both the mRNA and protein levels were further analyzed in individual samples of NC (n = 20), AD (n = 39), and AC (n = 24) by quantitative reverse transcriptase PCR. Individual samples of NC and tumor tissue were distinguishable based on the mRNA levels of a set of 20 kinases. Altered expression of several of these kinases, including chaperone activity of bc1 complex-like (CABC1) kinase, bromodomain adjacent to zinc finger domain protein 1B (BAZ1B) kinase, calcium/calmodulin-dependent protein kinase type II subunit delta (CAMK2D), serine/threonine-protein kinase 24 (STK24), vaccinia-related kinase 3 (VRK3), and TAO kinase 3 (TAOK3), has not been previously reported in tumor tissue. These findings may have diagnostic potential and may lead to the development of novel targeted therapeutic interventions for colorectal cancer

    The trace fossil Lepidenteron lewesiensis: a taphonomic window on diversity of Late Cretaceous fishes

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    The trace fossil Lepidenteron lewesiensis (Mantell 1822) provides an exceptional taphonomic window to diversity of fishes as shown for the Upper Cretaceous of Poland, in the Middle Turonian–Lower Maastrichtian deposits of the Opole Trough, Miechów Trough, Mazury-Podlasie Homocline, and SE part of the Border Synclinorium. Lepidenteron lewesiensis is an unbranched burrow lined with small fish scales and bones, without a constructed wall. It contains scales, vertebrae, and bones of the head belonging to ten taxa of teleostean fishes: two undetermined teleosteans, six undetermined Clupeocephala, one Dercetidae, and one undetermined euteleostean. The preservation of fish remains suggests that fishes were pulled down into the burrow by an animal, probably by eunicid polychaetes.Das Spurenfossil Lepidenteron lewesiensis (Mantell 1822) ermöglicht einen biostratinomischen Einblick in die Diversität von Fischen, wie Fossilmaterial aus der Oberkreide von Polen zeigt. Es stammt aus dem Mittelturonium bis Untermaastrichtium des südöstlichen Abschnittes der Grenz-Synklinale, dem Opolen-Trog, dem Miechów-Trog und der Masuren-Podlachien-Homoklinale. L. lewesiensis ist ein unverzweigter Grabgang ohne ausgekleidete Wände, dessen Ränder von kleinen Fischschuppen und—knochen gebildet werden. Diese setzen sich aus Schuppen, Wirbel und Schädelknochen von zehn Teleostei-Taxa zusammen und zwar aus zwei unbestimmte Teleosteer, sechs unbestimmten Clupeocephala, einem Dercetidae und einem unbestimmten Euteleostei. Die Erhaltung der Fischüberreste deutet darauf hin, dass die Fische von einem Tier, wahrscheinlich einem Polychaeten der Familie Eunicidae, in den Bau gezogen wurden.We are very grateful to Dr. Lionel Cavin (Geneva) and the anonymous reviewer for constructive comments on an earlier version of the manuscript. Additional support was provided by the Jagiellonian University (DS funds), National Science Center (Grant Number: PRO-2011/01/N/ST10/07717), and the Laboratory of Geology (University of Lodz) BSt Grant No. 560/844. We are grateful to Dr. Johann Egger (Wien) and Kilian Eichenseer M.Sc. (Erlangen) for help with translating the abstract into German. We are grateful to Dr. Ursula Göhlich (Wien) for access to the Dercetis specimen

    Cyclic sedimentation in the Middle Jurassic of central Poland

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    Nine boreholes were drilled in the late eighties in central Poland to investigate the Middle Jurassic sedimentary successions. The boreholes were arranged in three lines (Ciechocinek, Brześć Kujawski and Wojszyce lines) running across three anticlines underlain by salt pillows. Long intervals of boreholes have been cored, often with 100% core recovery, thus enabling a detailed examination of sedimentary evolution. Sequences are composed of a full range of clastic rocks, from conglomerates through sandstones and heteroliths to shales. They are arranged in sedimentary cycles, predominantly regressive (coarsening upwards). These are interpreted as deposited in a shallow, wave/storm-dominated, shelf environment, each cycle being a result of progradation of fore-shore to near-shore heteroliths and sands over the shales of an open sea. The basin was probably non-tidal or microtidal. These essential (lower order) cycles, equivalents of the IVth order cycles in the world-wide scheme, are assembled in higher order cycles which resemble the IIIrd order cycles of that scheme. The bases of the higher order cycles are good lithostratigraphic markers, three of them being probably equivalents of chronostratigraphic boundaries (bases of the upper Aalenian, upper Bajocian and Bathonian, respectively). Correlation of borehole sections points to limited salt movement of the Ciechocinek and Wojszyce salt pillows during the Middle Jurassic. These are indicated, first of all, by thickness reductions seen in boreholes located above the tops of salt pillows. In the Ciechocinek area, the upward movement of salt occurred during the latest Bajocian/earliest Bathonian while in the Wojszyce area - during the early Bathonian. Coarser clastics were shed into the basin from the south-west, north-west (along the Mid-Polish Trough) and north-east during the Aalenian, and mainly from the north-east (from the East European Craton) in later times

    Comput. Biol. Med.

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    We have developed an integrated tool for statistical analysis of large-scale LC-MS profiles of complex protein mixtures comprising a set of procedures for data processing, selection of biomarkers used in early diagnostic and classification of patients based on their peptide mass fingerprints. Here, a novel boosting technique is proposed, which is embedded in our framework for MS data analysis. Our boosting scheme is based on Hannan-consistent game playing strategies. We analyze boosting from a game-theoretic perspective and define a new class of boosting algorithms called H-boosting methods. In the experimental part of this work we apply the new classifier together with classical and state-of-the-art algorithms to classify ovarian cancer and cystic fibrosis patients based on peptide mass spectra. The methods developed here provide automatic, general, and efficient means for processing of large scale LC-MS datasets. Good classification results suggest that our approach is able to uncover valuable information to support medical diagnosis

    Systematic bioinformatics and experimental validation of yeast complexes reduces the rate of attrition during structural investigations.

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    For high-throughput structural studies of protein complexes of composition inferred from proteomics data, it is crucial that candidate complexes are selected accurately. Herein, we exemplify a procedure that combines a bioinformatics tool for complex selection with in vivo validation, to deliver structural results in a medium-throughout manner. We have selected a set of 20 yeast complexes, which were predicted to be feasible by either an automated bioinformatics algorithm, by manual inspection of primary data, or by literature searches. These complexes were validated with two straightforward and efficient biochemical assays, and heterologous expression technologies of complex components were then used to produce the complexes to assess their feasibility experimentally. Approximately one-half of the selected complexes were useful for structural studies, and we detail one particular success story. Our results underscore the importance of accurate target selection and validation in avoiding transient, unstable, or simply nonexistent complexes from the outset
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