The C-terminal domain from S. cerevisiae Pat1 displays two conserved regions involved in decapping factor recruitment

Eukaryotic mRNA decay is a highly regulated process allowing cells to rapidly modulate protein production in response to internal and environmental cues. Mature translatable eukaryotic mRNAs are protected from fast and uncontrolled degradation in the cytoplasm by two cis-acting stability determinants: a methylguanosine (m(7)G) cap and a poly(A) tail at their 5' and 3' extremities, respectively. The hydrolysis of the m(7)G cap structure, known as decapping, is performed by the complex composed of the Dcp2 catalytic subunit and its partner Dcp1. The Dcp1-Dcp2 decapping complex has a low intrinsic activity and requires accessory factors to be fully active. Among these factors, Pat1 is considered to be a central scaffolding protein involved in Dcp2 activation but also in inhibition of translation initiation. Here, we present the structural and functional study of the C-terminal domain from S. cerevisiae Pat1 protein. We have identified two conserved and functionally important regions located at both extremities of the domain. The first region is involved in binding to Lsm1-7 complex. The second patch is specific for fungal proteins and is responsible for Pat1 interaction with Edc3. These observations support the plasticity of the protein interaction network involved in mRNA decay and show that evolution has extended the C-terminal alpha-helical domain from fungal Pat1 proteins to generate a new binding platform for protein partners

Switchgrass (Panicum virgatum L.) polyubiquitin gene (PvUbi1 and PvUbi2) promoters for use in plant transformation

<p>Abstract</p> <p>Background</p> <p>The ubiquitin protein is present in all eukaryotic cells and promoters from ubiquitin genes are good candidates to regulate the constitutive expression of transgenes in plants. Therefore, two switchgrass (<it>Panicum virgatum </it>L.) ubiquitin genes (<it>PvUbi1 </it>and <it>PvUbi2</it>) were cloned and characterized. Reporter constructs were produced containing the isolated 5' upstream regulatory regions of the coding sequences (i.e. <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters) fused to the <it>uidA </it>coding region (<it>GUS</it>) and tested for transient and stable expression in a variety of plant species and tissues.</p> <p>Results</p> <p><it>PvUbi1 </it>consists of 607 bp containing <it>cis</it>-acting regulatory elements, a 5' untranslated region (UTR) containing a 93 bp non-coding exon and a 1291 bp intron, and a 918 bp open reading frame (ORF) that encodes four tandem, head -to-tail ubiquitin monomer repeats followed by a 191 bp 3' UTR. <it>PvUbi2 </it>consists of 692 bp containing <it>cis</it>-acting regulatory elements, a 5' UTR containing a 97 bp non-coding exon and a 1072 bp intron, a 1146 bp ORF that encodes five tandem ubiquitin monomer repeats and a 183 bp 3' UTR. <it>PvUbi1 </it>and <it>PvUbi2 </it>were expressed in all examined switchgrass tissues as measured by qRT-PCR. Using biolistic bombardment, <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters showed strong expression in switchgrass and rice callus, equaling or surpassing the expression levels of the CaMV <it>35S, 2x35S, ZmUbi1</it>, and <it>OsAct1 </it>promoters. GUS staining following stable transformation in rice demonstrated that the <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters drove expression in all examined tissues. When stably transformed into tobacco (<it>Nicotiana tabacum</it>), the <it>PvUbi2+3 </it>and <it>PvUbi2+9 </it>promoter fusion variants showed expression in vascular and reproductive tissues.</p> <p>Conclusions</p> <p>The <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters drive expression in switchgrass, rice and tobacco and are strong constitutive promoter candidates that will be useful in genetic transformation of monocots and dicots.</p

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Breast cancer patients treated with intrathecal therapy for leptomeningeal metastases in a large real-life database

International audienceBACKGROUND: Leptomeningeal metastasis (LM) is a rare complication of metastatic breast cancer (MBC), with high morbidity/mortality rates. Our study aimed to describe the largest-to-date real-life population of MBC patients treated with intrathecal (IT) therapy and to evaluate prognostic models. METHODS: The Epidemiological Strategy and Medical Economics (ESME) MBC database (NCT03275311) includes all consecutive patients who have initiated treatment for MBC since 2008. Overall survival (OS) of patients treated with IT therapy was estimated using the Kaplan-Meier method. Prognostic models were constructed using Cox proportional hazards models. Performance was evaluated using C-index and calibration plots. RESULTS: Of the 22 266 patients included in the database between 2008 and 2016, 312 received IT therapy and were selected for our analysis. Compared with non-IT-treated patients, IT-treated patients were younger at MBC relapse (median age: 52 years versus 61 years) and more often had lobular histology (23.4% versus 12.7%) or triple-negative subtype (24.7% versus 13.3%) (all P < 0.001). Median OS was 4.5 months [95% confidence interval (CI) 3.8-5.6] and 1-year survival rate was 25.6%. Significant prognostic factors associated with poorer outcome on multivariable analysis were triple-negative subtype (hazard ratio 1.81, 95% CI 1.32-2.47), treatment line ≥3 (hazard ratio 1.88, 95% CI 1.30-2.73), ≥3 other metastatic sites (hazard ratio 1.33, 95% CI 1.01-1.74) and IT cytarabine or thiotepa versus methotrexate (hazard ratio 1.68, 95% CI 1.28-2.22), while concomitant systemic therapy was associated with better OS (hazard ratio 0.47, 95% CI 0.35-0.62) (all P < 0.001). We validated two previously published prognostic scores, the Curie score and the Breast-graded prognostic assessment, both with C-index of 0.57. CONCLUSIONS: MBC patients with LM treated with IT therapy have a poor prognosis. We could identify a subgroup of patients with better prognosis, when concomitant systemic therapy and IT methotrexate were used

Olaparib plus Bevacizumab as First-Line Maintenance in Ovarian Cancer

BACKGROUND: Olaparib has shown significant clinical benefit as maintenance therapy in women with newly diagnosed advanced ovarian cancer with a BRCA mutation. The effect of combining maintenance olaparib and bevacizumab in patients regardless of BRCA mutation status is unknown. METHODS: We conducted a randomized, double-blind, international phase 3 trial. Eligible patients had newly diagnosed, advanced, high-grade ovarian cancer and were having a response after first-line platinum-taxane chemotherapy plus bevacizumab. Patients were eligible regardless of surgical outcome or BRCA mutation status. Patients were randomly assigned in a 2:1 ratio to receive olaparib tablets (300 mg twice daily) or placebo for up to 24 months; all the patients received bevacizumab at a dose of 15 mg per kilogram of body weight every 3 weeks for up to 15 months in total. The primary end point was the time from randomization until investigator-assessed disease progression or death. RESULTS: Of the 806 patients who underwent randomization, 537 were assigned to receive olaparib and 269 to receive placebo. After a median follow-up of 22.9 months, the median progression-free survival was 22.1 months with olaparib plus bevacizumab and 16.6 months with placebo plus bevacizumab (hazard ratio for disease progression or death, 0.59; 95% confidence interval [CI], 0.49 to 0.72; P<0.001). The hazard ratio (olaparib group vs. placebo group) for disease progression or death was 0.33 (95% CI, 0.25 to 0.45) in patients with tumors positive for homologous-recombination deficiency (HRD), including tumors that had BRCA mutations (median progression-free survival, 37.2 vs. 17.7 months), and 0.43 (95% CI, 0.28 to 0.66) in patients with HRD-positive tumors that did not have BRCA mutations (median progression-free survival, 28.1 vs. 16.6 months). Adverse events were consistent with the established safety profiles of olaparib and bevacizumab. CONCLUSIONS: In patients with advanced ovarian cancer receiving first-line standard therapy including bevacizumab, the addition of maintenance olaparib provided a significant progression-free survival benefit, which was substantial in patients with HRD-positive tumors, including those without a BRCA mutation. (Funded by ARCAGY Research and others; PAOLA-1 ClinicalTrials.gov number, NCT02477644.).status: publishe

Olaparib plus Bevacizumab as First-Line Maintenance in Ovarian Cancer

BACKGROUNDOlaparib has shown significant clinical benefit as maintenance therapy in women with newly diagnosed advanced ovarian cancer with a BRCA mutation. The effect of combining maintenance olaparib and bevacizumab in patients regardless of BRCA mutation status is unknown.METHODSWe conducted a randomized, double-blind, international phase 3 trial. Eligible patients had newly diagnosed, advanced, high-grade ovarian cancer and were having a response after first-line platinum-taxane chemotherapy plus bevacizumab. Patients were eligible regardless of surgical outcome or BRCA mutation status. Patients were randomly assigned in a 2:1 ratio to receive olaparib tablets (300 mg twice daily) or placebo for up to 24 months; all the patients received bevacizumab at a dose of 15 mg per kilogram of body weight every 3 weeks for up to 15 months in total. The primary end point was the time from randomization until investigator-assessed disease progression or death.RESULTSOf the 806 patients who underwent randomization, 537 were assigned to receive olaparib and 269 to receive placebo. After a median follow-up of 22.9 months, the median progression-free survival was 22.1 months with olaparib plus bevacizumab and 16.6 months with placebo plus bevacizumab (hazard ratio for disease progression or death, 0.59; 95% confidence interval [CI], 0.49 to 0.72; P&lt;0.001). The hazard ratio (olaparib group vs. placebo group) for disease progression or death was 0.33 (95% CI, 0.25 to 0.45) in patients with tumors positive for homologous-recombination deficiency (HRD), including tumors that had BRCA mutations (median progression-free survival, 37.2 vs. 17.7 months), and 0.43 (95% CI, 0.28 to 0.66) in patients with HRD-positive tumors that did not have BRCA mutations (median progression-free survival, 28.1 vs. 16.6 months). Adverse events were consistent with the established safety profiles of olaparib and bevacizumab.CONCLUSIONSIn patients with advanced ovarian cancer receiving first-line standard therapy including bevacizumab, the addition of maintenance olaparib provided a significant progression-free survival benefit, which was substantial in patients with HRD-positive tumors, including those without a BRCA mutation