Cms1 coordinates stepwise local 90S pre-ribosome assembly with timely snR83 release.

Ribosome synthesis begins in the nucleolus with 90S pre-ribosome construction, but little is known about how the many different snoRNAs that modify the pre-rRNA are timely guided to their target sites. Here, we report a role for Cms1 in such a process. Initially, we discovered CMS1 as a null suppressor of a nop14 mutant impaired in Rrp12-Enp1 factor recruitment to the 90S.

Global health: an order struggling to keep up with globalization.

Do global health institutions keep up with globalization forces? We contend that they seriously lag behind. While medical knowledge becomes more and more refined in showing how diseases spread globally, the political order meant to address this problem is barely global. It is global in terms of the promises it makes in declarations and even legally binding instruments (institutional foreground).

Correction: Mpp10 represents a platform for the interaction of multiple factors within the 90S pre-ribosome.

[This corrects the article DOI: 10.1371/journal.pone.

Mpp10 represents a platform for the interaction of multiple factors within the 90S pre-ribosome.

In eukaryotes, ribosome assembly is a highly complex process that involves more than 200 assembly factors that ensure the folding, modification and processing of the different rRNA species as well as the timely association of ribosomal proteins. One of these factors, Mpp10 associates with Imp3 and Imp4 to form a complex that is essential for the normal production of the 18S rRNA. Here we report the crystal structure of a complex between Imp4 and a short helical element of Mpp10 to a resolution of 1.

Structural basis for 5'-ETS recognition by Utp4 at the early stages of ribosome biogenesis.

Eukaryotic ribosome biogenesis begins with the co-transcriptional assembly of the 90S pre-ribosome. The 'U three protein' (UTP) complexes and snoRNP particles arrange around the nascent pre-ribosomal RNA chaperoning its folding and further maturation. The earliest event in this hierarchical process is the binding of the UTP-A complex to the 5'-end of the pre-ribosomal RNA (5'-ETS).

Interaction network of the ribosome assembly machinery from a eukaryotic thermophile.

Ribosome biogenesis in eukaryotic cells is a highly dynamic and complex process innately linked to cell proliferation. The assembly of ribosomes is driven by a myriad of biogenesis factors that shape pre-ribosomal particles by processing and folding the ribosomal RNA and incorporating ribosomal proteins. Biochemical approaches allowed the isolation and characterization of pre-ribosomal particles from Saccharomyces cerevisiae, which lead to a spatiotemporal map of biogenesis intermediates along the path from the nucleolus to the cytoplasm.

Architecture of the 90S Pre-ribosome: A Structural View on the Birth of the Eukaryotic Ribosome.

The 90S pre-ribosome is an early biogenesis intermediate formed during co-transcriptional ribosome formation, composed of ∼70 assembly factors and several small nucleolar RNAs (snoRNAs) that associate with nascent pre-rRNA. We report the cryo-EM structure of the Chaetomium thermophilum 90S pre-ribosome, revealing how a network of biogenesis factors including 19 β-propellers and large α-solenoid proteins engulfs the pre-rRNA. Within the 90S pre-ribosome, we identify the UTP-A, UTP-B, Mpp10-Imp3-Imp4, Bms1-Rcl1, and U3 snoRNP modules, which are organized around 5'-ETS and partially folded 18S rRNA.

Glycogen synthase kinase-3 inhibitors augment TRAIL-induced apoptotic death in human hepatoma cells.

Hepatocellular carcinoma (HCC) displays a striking resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Therefore, the characterization of pharmacological agents that overcome this resistance may provide new therapeutic modalities for HCC. Here, we examined whether glycogen synthase kinase-3 (GSK-3) inhibitors could restore TRAIL sensitivity in hepatoma cells.

Uridine abrogates the adverse effects of antiretroviral pyrimidine analogues on adipose cell functions.

Objectives: Side effects of antiretroviral treatment such as lipoatrophy have been mainly attributed to mitochondrial toxicity of nucleoside reverse transcriptase inhibitors (NRTIs). We assessed whether uridine can abrogate the adverse effects of NRTIs on adipocyte functions.

Methods: 3T3-F442A preadipocytes were exposed to stavudine (d4T; 10 microM), zidovudine (ZDV; 1 microM), zalcitabine (ddC; 0.

[Inhibition of phosphatidylethanolamine and phosphatidylinositol synthesis, alteration of the G0 and G1 cell cycle phases and spontaneous apoptosis in lymphocytes from patients under immunosuppressive treatment].

Lymphocytes from patients treated with immunosuppressive agents were cultured for 48 hours either with or without concanavalin A. Phospholipid synthesis was then studied using 32p pulse-incorporation (5-hours pulses). Phosphatidylethanolamine synthesis was strongly decreased under immunosuppressive treatment: 1.

Increased anticancer activity of the thymidylate synthase inhibitor BGC9331 combined with the topoisomerase I inhibitor SN-38 in human colorectal and breast cancer cells: induction of apoptosis and ROCK cleavage through caspase-3-dependent and -independent mechanisms.

The folate analogue BGC9331 is a new thymidylate synthase (TS) inhibitor showing a broad spectrum of cyto-toxic activity against several human solid tumors, including colorectal cancer. In this study, we investigated the anticancer activity of BGC9331 either alone or combined with 5-fluorouracil (5-FU), MTA (multi-target antifolate), oxali-platin and SN-38, the active metabolite of the topoisomerase I inhibitor CPT-11. The antiproliferative activity of each drug and BGC9331-based combinations was investigated in the HT-29 human colorectal cancer cell line and its HT-29/5-FU counterparts selected for resistance to 5-FU.

GSK-3beta reactivation with LY294002 sensitizes hepatoma cells to chemotherapy-induced apoptosis.

Constitutive activation of phosphatidylinositol 3-kinase (PI3K) confers resistance to apoptotic stimuli induced by chemotherapeutic agents in a variety of cancer cells. Therefore, the comprehension of mechanisms whereby PI3K downregulation interferes with chemotherapy is of major clinical interest for the elaboration of combined anticancer treatment modalities. Here, we examined the molecular mechanisms whereby the PI3K inhibitor LY294002 sensitized p53- and Fas-deficient hepatoma cells to etoposide and camptothecin.

Antiretroviral drugs with adverse effects on adipocyte lipid metabolism and survival alter the expression and secretion of proinflammatory cytokines and adiponectin in vitro.

Objective: The lipodystrophy syndrome is a major adverse effect of highly active antiretroviral therapy (HAART), associated with altered circulating levels and adipose tissue mRNA expression of proinflammatory cytokines interleukin-6 (IL-6) and tumour necrosis factor (TNF)alpha, and adiponectin. Proinflammatory cytokines and adiponectin, which are secreted by adipose tissue, regulate fat metabolism, insulin sensitivity and adipose cell apoptosis. We examined the direct effects of individual antiretrovirals on lipid metabolism and cytokine and adiponectin production by cultured adipocytes.

The HIV-1 nucleoside reverse transcriptase inhibitors stavudine and zidovudine alter adipocyte functions in vitro.

Objectives: Nucleoside analogues are suspected of playing a role in peripheral fat loss in patients during long-term treatment with antiretroviral drugs.

Design And Methods: We compared the long-term effects of stavudine (10 microM), zidovudine (1 muM), didanosine (10 microM), abacavir (4 microM), lamivudine (10 microM), and tenofovir (1 microM), near their maximum concentration values, on the differentiation, lipid accumulation, survival and mitochondrial function of differentiating 3T3-F442A and differentiated 3T3-L1 adipocytes.

Results: None of the nucleoside reverse transcriptase inhibitors (NRTI) markedly altered the differentiation of 3T3-F442A cells, as shown by the unmodified percentage of cells with lipid droplets on day 7 and the expression of the early differentiation markers CCAAT/enhancer binding protein (C/EBP) beta (on day 2) and sterol regulatory element-binding protein.

GSK-3beta inhibition by lithium confers resistance to chemotherapy-induced apoptosis through the repression of CD95 (Fas/APO-1) expression.

Lithium exerts neuroprotective actions that involve the inhibition of glycogen synthase kinase-3beta (GSK-3beta). Otherwise, recent studies suggest that sustained GSK-3beta inhibition is a hallmark of tumorigenesis. In this context, the present study was undertaken to examine whether lithium modulated cancer cell sensitivity to apoptosis induced by chemotherapy agents.

Thermal enhancement of oxaliplatin-induced inhibition of cell proliferation and cell cycle progression in human carcinoma cell lines.

Hyperthermia is used to treat intraperitoneal colorectal carcinomatosis. In this setting, the molecular effects of oxaliplatin and hyperthermia, in combination and alone, were deciphered in ovarian and colon cancer cells. The combined antiproliferative effects of hyperthermia and oxaliplatin (Eloxatine) on human IGROV-1 ovarian carcinoma, Caco-2 and HT-29 colon carcinoma cell lines were investigated by cell viability test, cell cycle analysis and modulation of expression of cell cycle-related proteins.

Some HIV protease inhibitors alter lamin A/C maturation and stability, SREBP-1 nuclear localization and adipocyte differentiation.

Objectives: To study whether HIV protease inhibitors could induce nuclear lamina alterations in adipocytes as observed in a genetic form of lipodystrophy due to lamin A/C mutation.

Design: We have previously observed that indinavir (IDV) impairs adipocyte differentiation and sterol regulatory element-binding protein-1 (SREBP-1) nuclear localization in 3T3-F442A adipocytes. We compared here the effects of IDV with that produced by two other PIs, nelfinavir (NFV) and amprenavir (APV) on adipose conversion, cellular localization of SREBP-1, nuclear morphology, and maturation and stability of the lamina network.

Butyrate-treated colonic Caco-2 cells exhibit defective integrin-mediated signaling together with increased apoptosis and differentiation.

We previously reported that the enterocytic differentiation of human colonic Caco-2 cells correlated with alterations in integrin signaling. We now investigated whether differentiation and apoptosis of Caco-2 cells induced by the short-chain fatty acid butyrate (NaBT) was associated with alterations in the integrin-mediated signaling pathway with special interest in the expression and activity of focal adhesion kinase (FAK), of the downstream phosphatidylinositol 3'-kinase (PI 3-kinase)-Akt pathway and in the role of the nuclear factor kappaB (NF-kappaB). NaBT increased the level of sucrase.

The c-kit tyrosine kinase inhibitor STI571 for colorectal cancer therapy.

The c-kit tyrosine kinase inhibitor STI571 exhibits a substantial therapeutic activity in patients with chronic myeloid leukemia and gastrointestinal stromal tumors respectively associated with constitutive activation of the BCR-ABL and c-kit tyrosine kinases. Human colorectal tumors also express the c-kit proto-oncogene. The present study focuses on the anticancer activity of STI571 in human colorectal tumor cells in vitro and in vivo.

The nuclear pore complex is involved in nuclear transfer of plasmid DNA condensed with an oligolysine-RGD peptide containing nuclear localisation properties.

One of the major barriers to efficient gene transfer and expression of nonviral vectors for gene therapy is passage across the nuclear envelope. We have previously shown that an oligolysine-RGD peptide that condenses plasmid DNA and binds to cell surface integrins can mediate increased internalisation of plasmid DNA into cells and synergistic enhancement of gene expression when complexed to a cationic lipid. In this report, we show that this enhancement is due to increased nuclear transfer of the plasmid DNA.

Butyrate and trichostatin A effects on the proliferation/differentiation of human intestinal epithelial cells: induction of cyclin D3 and p21 expression.

Background: Sodium butyrate, a product of colonic bacterial fermentation, is able to inhibit cell proliferation and to stimulate cell differentiation of colonic epithelial cell lines. It has been proposed that these cellular effects could be linked to its ability to cause hyperacetylation of histone through the inhibition of histone deacetylase.

Aim: To analyse the molecular mechanisms of butyrate action on cell proliferation/differentiation and to compare them with those of trichostatin A, a well known inhibitor of histone deacetylase.

Cell delivery, intracellular trafficking and expression of an integrin-mediated gene transfer vector in tracheal epithelial cells.

The mechanism of cell entry and intracellular fate of a gene transfer vector composed of a receptor-targeting, DNA-condensing peptide, RGD-oligolysine, a luciferase encoding plasmid DNA (pDNA) and a cationic liposome was examined. We demonstrate by confocal microscopy, electron microscopy and subcellular fractionation that the major mechanism of entry of the vector is endocytic. The vector complex rapidly (5 min) internalizes into early endosomes, then late endosomes and lysosomes.

Enterocytic differentiation of the human Caco-2 cell line correlates with alterations in integrin signaling.

We previously reported that the enterocytic differentiation of human colonic Caco-2 cells correlated with down-regulation of fibronectin (FN) and laminin (LN), two extracellular matrix components interacting with cell surface integrin receptors. We now investigated whether Caco-2 cell differentiation was associated with alterations in integrin signaling with special interest in the expression and activity of focal adhesion kinase (FAK) and mitogen-activated protein (MAP) kinase. The differentiation of Caco-2 cells was associated with: 1) down-regulation of beta1 integrin expression at the mRNA and protein levels; 2) increased FAK expression together with decreased FAK autophosphorylation; 3) decreased FAK's ability to associate with PI3-kinase and pp60c-src; and 4) increased MAP kinase expression along with decreased MAP activity.

Liposomes enhance delivery and expression of an RGD-oligolysine gene transfer vector in human tracheal cells.

Nonviral gene delivery systems consist predominantly of lipoplexes or receptor-targeting and nontargeting polyplexes. We examined integrin-mediated gene delivery using an Arg-Gly-Asp/oligo-L-lysine ([K]16RGD) cyclic peptide and investigated its gene transfer efficiency when associated with a cationic liposome. We demonstrated that human cystic fibrosis and noncystic fibrosis tracheal epithelial cells in culture express integrins that recognise the RGD integrin-binding motif.

Compensatory apoptosis in response to SV40 large T antigen expression in the liver.

Transgenesis allows the in vivo determination of the effects of oncogene expression in normal tissues. In an attempt to understand the mechanism underlying liver transformation, we have previously created transgenic mice carrying the SV40 early gene sequences, which developed hepatocarcinoma in a reproducible way. In the present study, we show that constant expression of the transgene was directly correlated to an abnormally increased hepatocyte proliferation, even at the adult stage.