排序方式: 共有43条查询结果,搜索用时 14 毫秒
1.
Gandin V Miluzio A Barbieri AM Beugnet A Kiyokawa H Marchisio PC Biffo S 《Nature》2008,455(7213):684-688
Cell growth and proliferation require coordinated ribosomal biogenesis and translation. Eukaryotic initiation factors (eIFs) control translation at the rate-limiting step of initiation. So far, only two eIFs connect extracellular stimuli to global translation rates: eIF4E acts in the eIF4F complex and regulates binding of capped messenger RNA to 40S subunits, downstream of growth factors, and eIF2 controls loading of the ternary complex on the 40S subunit and is inhibited on stress stimuli. No eIFs have been found to link extracellular stimuli to the activity of the large 60S ribosomal subunit. eIF6 binds 60S ribosomes precluding ribosome joining in vitro. However, studies in yeasts showed that eIF6 is required for ribosome biogenesis rather than translation. Here we show that mammalian eIF6 is required for efficient initiation of translation, in vivo. eIF6 null embryos are lethal at preimplantation. Heterozygous mice have 50% reduction of eIF6 levels in all tissues, and show reduced mass of hepatic and adipose tissues due to a lower number of cells and to impaired G1/S cell cycle progression. eIF6(+/-) cells retain sufficient nucleolar eIF6 and normal ribosome biogenesis. The liver of eIF6(+/-) mice displays an increase of 80S in polysomal profiles, indicating a defect in initiation of translation. Consistently, isolated hepatocytes have impaired insulin-stimulated translation. Heterozygous mouse embryonic fibroblasts recapitulate the organism phenotype and have normal ribosome biogenesis, reduced insulin-stimulated translation, and delayed G1/S phase progression. Furthermore, eIF6(+/-) cells are resistant to oncogene-induced transformation. Thus, eIF6 is the first eIF associated with the large 60S subunit that regulates translation in response to extracellular signals. 相似文献
2.
Haack TB Danhauser K Haberberger B Hoser J Strecker V Boehm D Uziel G Lamantea E Invernizzi F Poulton J Rolinski B Iuso A Biskup S Schmidt T Mewes HW Wittig I Meitinger T Zeviani M Prokisch H 《Nature genetics》2010,42(12):1131-1134
An isolated defect of respiratory chain complex I activity is a frequent biochemical abnormality in mitochondrial disorders. Despite intensive investigation in recent years, in most instances, the molecular basis underpinning complex I defects remains unknown. We report whole-exome sequencing of a single individual with severe, isolated complex I deficiency. This analysis, followed by filtering with a prioritization of mitochondrial proteins, led us to identify compound heterozygous mutations in ACAD9, which encodes a poorly understood member of the mitochondrial acyl-CoA dehydrogenase protein family. We demonstrated the pathogenic role of the ACAD9 variants by the correction of the complex I defect on expression of the wildtype ACAD9 protein in fibroblasts derived from affected individuals. ACAD9 screening of 120 additional complex I-defective index cases led us to identify two additional unrelated cases and a total of five pathogenic ACAD9 alleles. 相似文献
3.
Sieni E Cetica V Mastrodicasa E Pende D Moretta L Griffiths G Aricò M 《Cellular and molecular life sciences : CMLS》2012,69(1):29-40
Cytotoxic T lymphocytes, natural killer cells, and NKT cells are effector cells able to kill infected cells. In some inherited
human disorders, a defect in selected proteins involved in the cellular cytotoxicity mechanism results in specific clinical
syndromes, grouped under the name of familial hemophagocytic lymphohistiocytosis. Recent advances in genetic studies of these
patients has allowed the identification of different genetic subsets. Additional genetic immune deficiencies may also induce
a similar clinical picture. International cooperation and prospective trials resulted in refining the diagnostic and therapeutic
approach to these rare diseases with improved outcome but also with improved knowledge of the mechanisms underlying granule-mediated
cellular cytotoxicity in humans. 相似文献
4.
5.
Dense genotyping identifies and localizes multiple common and rare variant association signals in celiac disease 总被引:1,自引:0,他引:1
Trynka G Hunt KA Bockett NA Romanos J Mistry V Szperl A Bakker SF Bardella MT Bhaw-Rosun L Castillejo G de la Concha EG de Almeida RC Dias KR van Diemen CC Dubois PC Duerr RH Edkins S Franke L Fransen K Gutierrez J Heap GA Hrdlickova B Hunt S Izurieta LP Izzo V Joosten LA Langford C Mazzilli MC Mein CA Midah V Mitrovic M Mora B Morelli M Nutland S Núñez C Onengut-Gumuscu S Pearce K Platteel M Polanco I Potter S Ribes-Koninckx C Ricaño-Ponce I Rich SS Rybak A Santiago JL Senapati S Sood A 《Nature genetics》2011,43(12):1193-1201
Using variants from the 1000 Genomes Project pilot European CEU dataset and data from additional resequencing studies, we densely genotyped 183 non-HLA risk loci previously associated with immune-mediated diseases in 12,041 individuals with celiac disease (cases) and 12,228 controls. We identified 13 new celiac disease risk loci reaching genome-wide significance, bringing the number of known loci (including the HLA locus) to 40. We found multiple independent association signals at over one-third of these loci, a finding that is attributable to a combination of common, low-frequency and rare genetic variants. Compared to previously available data such as those from HapMap3, our dense genotyping in a large sample collection provided a higher resolution of the pattern of linkage disequilibrium and suggested localization of many signals to finer scale regions. In particular, 29 of the 54 fine-mapped signals seemed to be localized to single genes and, in some instances, to gene regulatory elements. Altogether, we define the complex genetic architecture of the risk regions of and refine the risk signals for celiac disease, providing the next step toward uncovering the causal mechanisms of the disease. 相似文献
6.
Bonatti E Ligi M Brunelli D Cipriani A Fabretti P Ferrante V Gasperini L Ottolini L 《Nature》2003,423(6939):499-505
A 20-Myr record of creation of oceanic lithosphere is exposed along a segment of the central Mid-Atlantic Ridge on an uplifted sliver of lithosphere. The degree of melting of the mantle that is upwelling below the ridge, estimated from the chemistry of the exposed mantle rocks, as well as crustal thickness inferred from gravity measurements, show oscillations of approximately 3-4 Myr superimposed on a longer-term steady increase with time. The time lag between oscillations of mantle melting and crustal thickness indicates that the mantle is upwelling at an average rate of approximately 25 mm x yr(-1), but this appears to vary through time. Slow-spreading lithosphere seems to form through dynamic pulses of mantle upwelling and melting, leading not only to along-axis segmentation but also to across-axis structural variability. Also, the central Mid-Atlantic Ridge appears to have become steadily hotter over the past 20 Myr, possibly owing to north-south mantle flow. 相似文献
7.
Emergence of KRAS mutations and acquired resistance to anti-EGFR therapy in colorectal cancer 总被引:1,自引:0,他引:1
Misale S Yaeger R Hobor S Scala E Janakiraman M Liska D Valtorta E Schiavo R Buscarino M Siravegna G Bencardino K Cercek A Chen CT Veronese S Zanon C Sartore-Bianchi A Gambacorta M Gallicchio M Vakiani E Boscaro V Medico E Weiser M Siena S Di Nicolantonio F Solit D Bardelli A 《Nature》2012,486(7404):532-536
A main limitation of therapies that selectively target kinase signalling pathways is the emergence of secondary drug resistance. Cetuximab, a monoclonal antibody that binds the extracellular domain of epidermal growth factor receptor (EGFR), is effective in a subset of KRAS wild-type metastatic colorectal cancers. After an initial response, secondary resistance invariably ensues, thereby limiting the clinical benefit of this drug. The molecular bases of secondary resistance to cetuximab in colorectal cancer are poorly understood. Here we show that molecular alterations (in most instances point mutations) of KRAS are causally associated with the onset of acquired resistance to anti-EGFR treatment in colorectal cancers. Expression of mutant KRAS under the control of its endogenous gene promoter was sufficient to confer cetuximab resistance, but resistant cells remained sensitive to combinatorial inhibition of EGFR and mitogen-activated protein-kinase kinase (MEK). Analysis of metastases from patients who developed resistance to cetuximab or panitumumab showed the emergence of KRAS amplification in one sample and acquisition of secondary KRAS mutations in 60% (6 out of 10) of the cases. KRAS mutant alleles were detectable in the blood of cetuximab-treated patients as early as 10 months before radiographic documentation of disease progression. In summary, the results identify KRAS mutations as frequent drivers of acquired resistance to cetuximab in colorectal cancers, indicate that the emergence of KRAS mutant clones can be detected non-invasively months before radiographic progression and suggest early initiation of a MEK inhibitor as a rational strategy for delaying or reversing drug resistance. 相似文献
8.
Systematic generation of high-resolution deletion coverage of the Drosophila melanogaster genome 总被引:1,自引:0,他引:1
Parks AL Cook KR Belvin M Dompe NA Fawcett R Huppert K Tan LR Winter CG Bogart KP Deal JE Deal-Herr ME Grant D Marcinko M Miyazaki WY Robertson S Shaw KJ Tabios M Vysotskaia V Zhao L Andrade RS Edgar KA Howie E Killpack K Milash B Norton A Thao D Whittaker K Winner MA Friedman L Margolis J Singer MA Kopczynski C Curtis D Kaufman TC Plowman GD Duyk G Francis-Lang HL 《Nature genetics》2004,36(3):288-292
In fruit fly research, chromosomal deletions are indispensable tools for mapping mutations, characterizing alleles and identifying interacting loci. Most widely used deletions were generated by irradiation or chemical mutagenesis. These methods are labor-intensive, generate random breakpoints and result in unwanted secondary mutations that can confound phenotypic analyses. Most of the existing deletions are large, have molecularly undefined endpoints and are maintained in genetically complex stocks. Furthermore, the existence of haplolethal or haplosterile loci makes the recovery of deletions of certain regions exceedingly difficult by traditional methods, resulting in gaps in coverage. Here we describe two methods that address these problems by providing for the systematic isolation of targeted deletions in the D. melanogaster genome. The first strategy used a P element-based technique to generate deletions that closely flank haploinsufficient genes and minimize undeleted regions. This deletion set has increased overall genomic coverage by 5-7%. The second strategy used FLP recombinase and the large array of FRT-bearing insertions described in the accompanying paper to generate 519 isogenic deletions with molecularly defined endpoints. This second deletion collection provides 56% genome coverage so far. The latter methodology enables the generation of small custom deletions with predictable endpoints throughout the genome and should make their isolation a simple and routine task. 相似文献
9.
Friederike Klempin Valentina Mosienko Susann Matthes Daniel C. Villela Mihail Todiras Josef M. Penninger Michael Bader Natalia Alenina 《Cellular and molecular life sciences : CMLS》2018,75(19):3625-3634
Physical exercise induces cell proliferation in the adult hippocampus in rodents. Serotonin (5-HT) and angiotensin (Ang) II are important mediators of the pro-mitotic effect of physical activity. Here, we examine precursor cells in the adult brain of mice lacking angiotensin-converting enzyme (ACE) 2, and explore the effect of an acute running stimulus on neurogenesis. ACE2 metabolizes Ang II to Ang-(1–7) and is essential for the intestinal uptake of tryptophan (Trp), the 5-HT precursor. In ACE2-deficient mice, we observed a decrease in brain 5-HT levels and no increase in the number of BrdU-positive cells following exercise. Targeting the Ang II/AT1 axis by blocking the receptor, or experimentally increasing Trp/5-HT levels in the brain of ACE2-deficient mice, did not rescue the running-induced effect. Furthermore, mice lacking the Ang-(1–7) receptor, Mas, presented a normal neurogenic response to exercise. Our results identify ACE2 as a novel factor required for exercise-dependent modulation of adult neurogenesis and essential for 5-HT metabolism. 相似文献
10.
Gabriele Eden Marco Archinti Ralitsa Arnaudova Giuseppina Andreotti Andrea Motta Federico Furlan Valentina Citro Maria Vittoria Cubellis Bernard Degryse 《Cellular and molecular life sciences : CMLS》2018,75(10):1889-1907
The urokinase receptor (uPAR) stimulates cell proliferation by forming a macromolecular complex with αvβ3 integrin and the epidermal growth factor receptor (EGFR, ErbB1 or HER1) that we name the uPAR proliferasome. uPAR transactivates EGFR, which in turn mediates uPAR-initiated mitogenic signal to the cell. EGFR activation and EGFR-dependent cell growth are blocked in the absence of uPAR expression or when uPAR activity is inhibited by antibodies against either uPAR or EGFR. The mitogenic sequence of uPAR corresponds to the D2A motif present in domain 2. NMR analysis revealed that D2A synthetic peptide has a particular three-dimensional structure, which is atypical for short peptides. D2A peptide is as effective as EGF in promoting EGFR phosphorylation and cell proliferation that were inhibited by AG1478, a specific inhibitor of the tyrosine kinase activity of EGFR. Both D2A and EGF failed to induce proliferation of NR6-EGFR-K721A cells expressing a kinase-defective mutant of EGFR. Moreover, D2A peptide and EGF phosphorylate ERK demonstrating the involvement of the MAP kinase signalling pathway. Altogether, this study reveals the importance of sequence D2A of uPAR, and the interdependence of uPAR and EGFR. 相似文献