20 results on '"Machado-Pinilla R"'
Search Results
2. MKP1/CL100 controls tumor growth and sensitivity to cisplatin in non-small-cell lung cancer
- Author
-
Chattopadhyay, S, Machado-Pinilla, R, Manguan-García, C, Belda-Iniesta, C, Moratilla, C, Cejas, P, Fresno-Vara, J A, de Castro-Carpeño, J, Casado, E, Nistal, M, Gonzalez-Barón, M, and Perona, R
- Published
- 2006
- Full Text
- View/download PDF
3. Expression of the genetic suppressor element 24.2 (GSE24.2) decreases DNA damage and oxidative stress in X-linked dyskeratosis congenita cells
- Author
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Manguan-Garcia C, Pintado-Berninches L, Carrillo J, Machado-Pinilla R, Sastre L, Pérez-Quilis C, Esmoris I, Gimeno A, García-Giménez JL, Pallardó FV, and Perona R
- Abstract
The predominant X-linked form of Dyskeratosis congenita results from mutations in DKC1, which encodes dyskerin, a protein required for ribosomal RNA modification that is also a component of the telomerase complex. We have previously found that expression of an internal fragment of dyskerin (GSE24.2) rescues telomerase activity in X-linked dyskeratosis congenita (X-DC) patient cells. Here we have found that an increased basal and induced DNA damage response occurred in X-DC cells in comparison with normal cells. DNA damage that is also localized in telomeres results in increased heterochromatin formation and senescence. Expression of a cDNA coding for GSE24.2 rescues both global and telomeric DNA damage. Furthermore, transfection of bacterial purified or a chemically synthesized GSE24.2 peptide is able to rescue basal DNA damage in X-DC cells. We have also observed an increase in oxidative stress in X-DC cells and expression of GSE24.2 was able to diminish it. Altogether our data indicated that supplying GSE24.2, either from a cDNA vector or as a peptide reduces the pathogenic effects of Dkc1 mutations and suggests a novel therapeutic approach.
- Published
- 2014
4. Expression of the genetic suppressor element 24.2 (GSE24.2) decreases DNA damage and oxidative stress in X-linked dyskeratosis congenita cells
- Author
-
Fundación Salud 2000, Generalitat Valenciana, Ministerio de Ciencia e Innovación (España), Centro de Investigación Biomédica en Red Enfermedades Raras (España), Manguan-García, Cristina, Pintado-Berninches, Laura, Carrillo, Jaime, Machado-Pinilla, R., Sastre, Leandro, Pallardó, Federico V., Perona Abellón, Rosario, Fundación Salud 2000, Generalitat Valenciana, Ministerio de Ciencia e Innovación (España), Centro de Investigación Biomédica en Red Enfermedades Raras (España), Manguan-García, Cristina, Pintado-Berninches, Laura, Carrillo, Jaime, Machado-Pinilla, R., Sastre, Leandro, Pallardó, Federico V., and Perona Abellón, Rosario
- Abstract
The predominant X-linked form of Dyskeratosis congenita results from mutations in DKC1, which encodes dyskerin, a protein required for ribosomal RNA modification that is also a component of the telomerase complex. We have previously found that expression of an internal fragment of dyskerin (GSE24.2) rescues telomerase activity in X-linked dyskeratosis congenita (X-DC) patient cells. Here we have found that an increased basal and induced DNA damage response occurred in X-DC cells in comparison with normal cells. DNA damage that is also localized in telomeres results in increased heterochromatin formation and senescence. Expression of a cDNA coding for GSE24.2 rescues both global and telomeric DNA damage. Furthermore, transfection of bacterial purified or a chemically synthesized GSE24.2 peptide is able to rescue basal DNA damage in X-DC cells. We have also observed an increase in oxidative stress in X-DC cells and expression of GSE24.2 was able to diminish it. Altogether our data indicated that supplying GSE24.2, either from a cDNA vector or as a peptide reduces the pathogenic effects of Dkc1 mutations and suggests a novel therapeutic approach.
- Published
- 2014
5. Uso de agentes inductores GSE24.2 para la elaboración de composiciones farmacéuticas para el tratamiento de enfermedades que cursan con senescencia celular
- Author
-
Perona Abellón, Rosario, Machado-Pinilla, R., Garzón, Leandro, and Sánchez-Pérez, Isabel
- Abstract
Uso de agentes inductores GSE24.2 para la elaboración de composiciones farmacéuticas para el tratamiento de enfermedades que cursan con senescencia celular. La presente invención describe el uso de un compuesto inductor o activador de la telomerasa en la elaboración de un medicamento o composición farmacéutica para el tratamiento de una enfermedad o situación patológica, preferentemente humana, causada por un proceso de senescencia relacionado con la disminución de los telómeros o con una alteración de la actividad de la telomerasa. Esta composición farmacéutica puede ser útil para un tratamiento regeneración tisular, por ejemplo de tejidos epiteliales o de células hematopoyéticas, e incluso para la inmortalización de células eucariotas para su uso en investigación o procesos biotecnológicos., Consejo Superior de Investigaciones Científicas (España), Universidad Autónoma de Madrid, B1 Patente con informe sobre el estado de la ténica
- Published
- 2007
6. Secuencia de nucleótidos y péptidos GSE 24.2 de la disquerina inductores de la actividad telomerasa, procedimiento de obtención, composiciones terapéuticas y sus aplicaciones
- Author
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Perona Abellón, Rosario, Machado-Pinilla, R., Sastre, Leandro, Sánchez-Pérez, Isabel, and Murguía, José Ramón
- Subjects
Nucleótidos ,Patente ,Péptidos ,Enfermedades neurodegenerativas - Abstract
Secuencia de nucleótidos y péptidos GSE 24.2 de la disquerina inductores de la actividad telomerasa, procedimiento de obtención, composiciones terapéuticas y sus aplicaciones. La presente invención describe un compuesto inductor o activador de la actividad telomerasa basado en la secuencia de nucleótidos del fragmento GSE 24.2 de la disquerina o la secuencia proteínica o peptídica codificado por dicha secuencia de nucleótidos. Igualmente forman parte vectores que comprenden dicha secuencia y células transformadas con la misma, y composiciones farmacéuticas que contienen todos estos elementos. Estas composiciones pueden ser utilizadas en el tratamiento de enfermedades del siguiente grupo: envejecimiento o aceleración del envejecimiento, enfermedades neurodegenerativas y disqueratosis congénita., Consejo Superior de Investigaciones Científicas (España), Universidad Autónoma de Madrid, Universidad Politécnica de Valencia, A1 Solicitud de patente con informe sobre el estado de la técnica
- Published
- 2005
7. Secuencias de nucleótidos y péptidos GSE 24.2 de disquerina que puede inducir actividad de la telomerasa, procedimiento para obtener la misma, composiciones terapéuticas y aplicaciones de la misma
- Author
-
Machado-Pinilla, R., Sastre, Leandro, Sánchez-Pérez, Isabel, Murguía, José Ramón, and Perona Abellón, Rosario
- Abstract
Secuencia de nucleótidos y péptidos GSE 24.2 de disquerina que puede inducir actividad de la telomerasa, procedimiento para obtener la misma, composiciones terapéuticas y aplicaciones de la misma. Sector biotecnológico con aplicaciones relacionadas con la salud humana, y más específicamente compuestos biológicos - secuencias de nucleótidos, péptidos y células humanas transformadas - con aplicaciones terapéuticas para los seres humanos., Consejo Superior de Investigaciones Científicas (España), Universidad Autónoma de Madrid, Universidad Politécnica de Valencia, T3 Traducción de patente europea
- Published
- 2005
8. Defects in mTR stability and telomerase activity produced by the Dkc1 A353V mutation in dyskeratosis congenita are rescued by a peptide from the dyskerin TruB domain
- Author
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Machado-Pinilla, R., Carrillo, Jaime, Manguan-García, Cristina, Sastre, Leandro, Perona Abellón, Rosario, Machado-Pinilla, R., Carrillo, Jaime, Manguan-García, Cristina, Sastre, Leandro, and Perona Abellón, Rosario
- Abstract
[Background]: The predominant X-linked form of dyskeratosis congenita results from mutations in dyskerin, a protein required for ribosomal RNA modification that is also a component of the telomerase complex. We have previously found that expression of an internal fragment of dyskerin (GSE24.2) rescues telomerase activity in X-linked dyskeratosis congenita (X-DC) patient cells. [Materials and Methods]: Here, we have generated F9 mouse cell lines expressing the most frequent mutation found in X-DC patients, A353V and study the effect of expressing the GSE24.2 cDNA or GSE24.2 peptide on telomerase activity by TRAP assay, and mTERT and mTR expression by Q-PCR. Point mutation in GSE24.2 residues were generated by site-directed mutagenesis. [Results]: Expression of GSE24.2 increases mTR and to a lesser extent mTERT RNA levels, and leads to recovery of telomerase activity. Point mutations in GSE24.2 residues known to be highly conserved and crucial for the pseudouridine-synthase activity of dyskerin abolished the effect of the peptide. Recovery of telomerase activity and increase in mTERT levels were found when the GSE24.2 peptide purified from bacteria was introduced into the cells. Moreover, mTR stability was also rescued by transfection of the peptide GSE24.2. [Discussion]: These data indicate that supplying GSE24.2, either from a cDNA vector, or as a peptide, can reduces the pathogenic effects of Dkc1 mutations and could form the basis of a novel therapeutic approach.
- Published
- 2012
9. Uso de agentes inductores GSE24.2 para la elaboración de composiciones farmacéuticas para el tratamiento de enfermedades que cursan con senescencia celular
- Author
-
Perona Abellón, Rosario, Machado-Pinilla, R., Garzón, Leandro, Sánchez-Pérez, Isabel, Perona Abellón, Rosario, Machado-Pinilla, R., Garzón, Leandro, and Sánchez-Pérez, Isabel
- Abstract
Uso de agentes inductores GSE24.2 para la elaboración de composiciones farmacéuticas para el tratamiento de enfermedades que cursan con senescencia celular. La presente invención describe el uso de un compuesto inductor o activador de la telomerasa en la elaboración de un medicamento o composición farmacéutica para el tratamiento de una enfermedad o situación patológica, preferentemente humana, causada por un proceso de senescencia relacionado con la disminución de los telómeros o con una alteración de la actividad de la telomerasa. Esta composición farmacéutica puede ser útil para un tratamiento regeneración tisular, por ejemplo de tejidos epiteliales o de células hematopoyéticas, e incluso para la inmortalización de células eucariotas para su uso en investigación o procesos biotecnológicos.
- Published
- 2011
10. Secuencias de nucleótidos y péptidos GSE 24.2 de disquerina que puede inducir actividad de la telomerasa, procedimiento para obtener la misma, composiciones terapéuticas y aplicaciones de la misma
- Author
-
Machado-Pinilla, R., Sastre, Leandro, Sánchez-Pérez, Isabel, Murguía, José Ramón, Perona Abellón, Rosario, Machado-Pinilla, R., Sastre, Leandro, Sánchez-Pérez, Isabel, Murguía, José Ramón, and Perona Abellón, Rosario
- Abstract
Secuencia de nucleótidos y péptidos GSE 24.2 de disquerina que puede inducir actividad de la telomerasa, procedimiento para obtener la misma, composiciones terapéuticas y aplicaciones de la misma. Sector biotecnológico con aplicaciones relacionadas con la salud humana, y más específicamente compuestos biológicos - secuencias de nucleótidos, péptidos y células humanas transformadas - con aplicaciones terapéuticas para los seres humanos.
- Published
- 2011
11. Secuencia de nucleótidos y péptidos GSE 24.2 de la disquerina inductores de la actividad telomerasa, procedimiento de obtención, composiciones terapéuticas y sus aplicaciones
- Author
-
Perona Abellón, Rosario, Machado-Pinilla, R., Sastre, Leandro, Sánchez-Pérez, Isabel, Murguía, José Ramón, Perona Abellón, Rosario, Machado-Pinilla, R., Sastre, Leandro, Sánchez-Pérez, Isabel, and Murguía, José Ramón
- Abstract
Secuencia de nucleótidos y péptidos GSE 24.2 de la disquerina inductores de la actividad telomerasa, procedimiento de obtención, composiciones terapéuticas y sus aplicaciones. La presente invención describe un compuesto inductor o activador de la actividad telomerasa basado en la secuencia de nucleótidos del fragmento GSE 24.2 de la disquerina o la secuencia proteínica o peptídica codificado por dicha secuencia de nucleótidos. Igualmente forman parte vectores que comprenden dicha secuencia y células transformadas con la misma, y composiciones farmacéuticas que contienen todos estos elementos. Estas composiciones pueden ser utilizadas en el tratamiento de enfermedades del siguiente grupo: envejecimiento o aceleración del envejecimiento, enfermedades neurodegenerativas y disqueratosis congénita.
- Published
- 2010
12. Use of inductor agents GSE24.2 for producing pharmaceutical compositions for treating illnesses relating to cellular senescence
- Author
-
Perona Abellón, Rosario, Sastre, Leandro, Machado-Pinilla, R., Sánchez-Pérez, Isabel, Perona Abellón, Rosario, Sastre, Leandro, Machado-Pinilla, R., and Sánchez-Pérez, Isabel
- Abstract
This invention relates to the use of an inductor or activator compound GSE24.2 for producing a medicament or a pharmaceutical composition for treating a preferably human illness or pathological situation caused by a senescence process. Said pharmaceutical composition can be useful for a treatment for regenerating tissues, for example of epithelial tissues or haematopoietic cells, and also for the immortalisation of eucaryotic cells in order to use of same in biotechnological investigation or processes., Esta invención relaciona al uso de un inductor o de un compuesto activador GSE24.2 para producir un medicamento o a una composición farmacéutica para tratar una enfermedad preferiblemente humana o una situación patológica causada por un procedimiento de la senectud. El bote dicho de la composición farmacéutica sea útil para un tratamiento para regenerar los tejidos, por ejemplo de tejidos epiteliales o de células haematopoietic, y también para el immortalisation del uso de las células eucarióticas para de mismo en la investigación o procedimientos biotechnological.
- Published
- 2010
13. Telomerase deficiency and cancer susceptibility syndromes
- Author
-
Perona Abellón, Rosario, Machado-Pinilla, R., Manguan-García, Cristina, Carrillo, Jaime, Perona Abellón, Rosario, Machado-Pinilla, R., Manguan-García, Cristina, and Carrillo, Jaime
- Abstract
Telomeres from most eukaryotes are composed of repeats of guanine-rich sequences whose main function is to preserve the end of the chromosomes. Telomeres are synthesised by a reverse transcriptase enzyme, telomerase (TERT), which forms part of a ribonucleoprotein complex containing also a RNA template molecule (TERC) and dyskerin. Exhaustion of telomeres during cell divisions triggers a DNA damage response that induces a senescence phenotype. The DNA damage machinery plays an essential role in maintaining the integrity of the genome and also detecting telomere shortening. However in some syndromes that involved mutations either in the telomerase complex genes or those involved in maintaining DNA secondary structure, such as the recQ helicase WRN, a higher frequency in the development of different types of malignancies is observed. We here describe the biology of some of these diseases, together with the molecular modifications in the telomerase complex genes and the impact of these alterations on the development of particular types of cancer. © 2009 Feseo.
- Published
- 2009
14. Role of CHK2 in cancer development
- Author
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Perona Abellón, Rosario, Moncho-Amor, Verónica, Machado-Pinilla, R., Belda-Iniesta, Cristobal, Sánchez-Pérez, Isabel, Perona Abellón, Rosario, Moncho-Amor, Verónica, Machado-Pinilla, R., Belda-Iniesta, Cristobal, and Sánchez-Pérez, Isabel
- Abstract
DNA repair pathways enable tumour cells to survive DNA damage induced by external agents such as therapeutic treatments. Signalling cascades involved in these pathways comprise the DNA-dependent protein kinase (DNA-PK), Ataxia-telangiectasia mutated (ATM), ATM and Rad3 related (ATR) and checkpoint kinases I and 2 (Chk1/Chk2), among others. ATM and ATR phosphorylate, respectively, Chk2 and Chk1, leading to activation of checkpoints. Chk2 acts as a signal distributor, dispersing checkpoint signal to downstream targets such as p53, Cdc25A, Cdc25C, BRCA1 and E2F1. A role of Chk2 as a candidate tumour suppressor has been suggested based on both mouse genetics and somatic tumour studies. We will discuss here the possible role of this kinase in human carcinogenesis and the possibility to use it as a target to increment DNA damage in cancer cells in response to DNA-damaging therapies.
- Published
- 2008
15. A dyskerin motif reactivates telomerase activity in X-linked dyskeratosis congenita and in telomerase-deficient human cells
- Author
-
Machado-Pinilla, R., Sánchez-Pérez, Isabel, Murguía, José Ramón, Sastre, Leandro, Perona Abellón, Rosario, Machado-Pinilla, R., Sánchez-Pérez, Isabel, Murguía, José Ramón, Sastre, Leandro, and Perona Abellón, Rosario
- Abstract
Dyskerin gene is mutated in patients with X-linked dyskeratosis congenita (X-DC), which results in greatly reduced levels of telomerase activity. A genetic suppressor element (GSE) termed GSE24-2 has been isolated in a screening for cisplatin resistance. GSE24-2-expressing cells presented impaired telomerase inhibition following in vitro exposure to chemotherapies, such as cisplatin, or telomerase inhibitors. The promoter of the telomerase component hTERT was constitutively activated in GSE24-2 cells in a c-myc expression-dependent manner. Deletion analyses and mutagenesis of the human c-myc promoter demonstrated that the target sequence for activation was the nuclease hypersensitive element-III (NHEIII) site located upstream to the P1 region of the promoter. Further, expression of GSE24-2 in cell lines derived from patients with X-DC and in VA13 cells induced increased hTERT RNA and hTR levels and recovery of telomerase activity. Finally, expression of GSE24-2 was able to rescue X-DC fibroblasts from premature senescence. These data demonstrate that this domain of dyskerin plays an important role in telomerase maintenance following cell insults such as cisplatin treatment, and in telomerase-defective cells in patients with X-DC. The expression of this dyskerin fragment has a dominant function in X-DC cells and could provide the basis for a therapeutic approach to this disease. © 2008 by The American Society of Hematology.
- Published
- 2008
16. MKP1/CL100 controls tumor growth and sensitivity to cisplatin in non-small-cell lung cancer
- Author
-
Chattopadhyay, S., Machado-Pinilla, R., Manguan-García, Cristina, Belda-Iniesta, Cristobal, Moratilla, Carmen, Fresno Vara, Juan Ángel, Castro Carpeño, Javier de, Casado, Enrique, Nistal, Manuel, González Barón, Manuel, Perona Abellón, Rosario, Chattopadhyay, S., Machado-Pinilla, R., Manguan-García, Cristina, Belda-Iniesta, Cristobal, Moratilla, Carmen, Fresno Vara, Juan Ángel, Castro Carpeño, Javier de, Casado, Enrique, Nistal, Manuel, González Barón, Manuel, and Perona Abellón, Rosario
- Abstract
Non-small-cell lung cancer (NSCLC) represents the most frequent and therapy-refractive sub-class of lung cancer. Improving apoptosis induction in NSCLC represents a logical way forward in treating this tumor. Cisplatin, a commonly used therapeutic agent in NSCLC, induces activation of N-terminal-c-Jun kinase (JNK) that, in turn, mediates induction of apoptosis. In analysing surgical tissue samples of NSCLC, we found that expression of MKP1/CL100, a negative regulator of JNK, showed a strong nuclear staining for tumor cells, whereas, in normal bronchial epithelia, MKP1 was localized in the cytoplasm as well as in nuclei. In the NSCLC-derived cell lines H-460 and H-23, we found that MKP1 was constitutively expressed. Expressing a small-interfering RNA (siRNA) vector for MKP1 in H-460 cells resulted in a more efficient activation by cisplatin of JNK and p38 than in the parental cells, and this correlated with a 10-fold increase in sensitivity to cisplatin. A similar response was also observed in H-460 and H-23 cells when treated with the MKP1 expression inhibitor RO-31-8220. Moreover, expression of a siRNA-MKP2, an MKP1-related phosphatase, had no effect on H-460 cell viability response to cisplatin. Tumors induced by H-460 cells expressing MKP1 siRNA grew slower in nu-/nu- mice and showed more susceptibility to cisplatin than parental cells, and resulted in an impaired growth of the tumor in mice. On the other hand, overexpression of MKP1 in the H-1299 NSCLC-derived cell line resulted in further resistance to cisplatin. Overall, the results showed that inhibition of MKP1 expression contributes to a slow down in cell growth in mice and an increase of cisplatin-induced cell death in NSCLC. As such, MKP1 can be an attractive target in sensitizing cells to cisplatin to increase the effectiveness of the drug in treating NSCLC. © 2006 Nature Publishing Group All rights reserved.
- Published
- 2006
17. IGFBP-3 hypermethylation-derived deficiency mediates cisplatin resistance in non-small-cell lung cancer
- Author
-
Ibanez de Caceres, I, primary, Cortes-Sempere, M, additional, Moratilla, C, additional, Machado-Pinilla, R, additional, Rodriguez-Fanjul, V, additional, Manguán-García, C, additional, Cejas, P, additional, López-Ríos, F, additional, Paz-Ares, L, additional, de CastroCarpeño, J, additional, Nistal, M, additional, Belda-Iniesta, C, additional, and Perona, R, additional
- Published
- 2009
- Full Text
- View/download PDF
18. Mechanism of the AAA+ ATPases pontin and reptin in the biogenesis of H/ACA RNPs.
- Author
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Machado-Pinilla R, Liger D, Leulliot N, and Meier UT
- Subjects
- ATPases Associated with Diverse Cellular Activities, Adenosine Triphosphatases antagonists & inhibitors, Adenosine Triphosphatases genetics, Adenosine Triphosphatases metabolism, Adenosine Triphosphatases physiology, Animals, Carrier Proteins antagonists & inhibitors, Carrier Proteins genetics, Carrier Proteins metabolism, Cells, Cultured, DNA Helicases antagonists & inhibitors, DNA Helicases genetics, DNA Helicases metabolism, Gene Expression Regulation, Enzymologic drug effects, Gene Expression Regulation, Enzymologic physiology, HeLa Cells, Humans, Mice, Models, Biological, Protein Multimerization genetics, Protein Multimerization physiology, RNA, Small Interfering pharmacology, Signal Transduction drug effects, Signal Transduction genetics, Signal Transduction physiology, Carrier Proteins physiology, DNA Helicases physiology, Macromolecular Substances metabolism, Ribonucleoproteins, Small Nuclear biosynthesis, Ribonucleoproteins, Small Nucleolar metabolism
- Abstract
The AAA+ ATPases pontin and reptin function in a staggering array of cellular processes including chromatin remodeling, transcriptional regulation, DNA damage repair, and assembly of macromolecular complexes, such as RNA polymerase II and small nucleolar (sno) RNPs. However, the molecular mechanism for all of these AAA+ ATPase associated activities is unknown. Here we document that, during the biogenesis of H/ACA RNPs (including telomerase), the assembly factor SHQ1 holds the pseudouridine synthase NAP57/dyskerin in a viselike grip, and that pontin and reptin (as components of the R2TP complex) are required to pry NAP57 from SHQ1. Significantly, the NAP57 domain captured by SHQ1 harbors most mutations underlying X-linked dyskeratosis congenita (X-DC) implicating the interface between the two proteins as a target of this bone marrow failure syndrome. Homing in on the essential first steps of H/ACA RNP biogenesis, our findings provide the first insight into the mechanism of action of pontin and reptin in the assembly of macromolecular complexes.
- Published
- 2012
- Full Text
- View/download PDF
19. The H/ACA RNP assembly factor SHQ1 functions as an RNA mimic.
- Author
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Walbott H, Machado-Pinilla R, Liger D, Blaud M, Réty S, Grozdanov PN, Godin K, van Tilbeurgh H, Varani G, Meier UT, and Leulliot N
- Subjects
- Cell Survival, Humans, Hydro-Lyases chemistry, Hydro-Lyases metabolism, Microtubule-Associated Proteins chemistry, Microtubule-Associated Proteins metabolism, Mutation, Nuclear Proteins genetics, Protein Binding, Protein Folding, Protein Structure, Tertiary, RNA, Fungal metabolism, Recombinant Proteins metabolism, Ribonucleoproteins, Small Nuclear chemistry, Ribonucleoproteins, Small Nuclear metabolism, Ribonucleoproteins, Small Nucleolar chemistry, Saccharomyces cerevisiae Proteins genetics, Models, Molecular, Molecular Mimicry, Nuclear Proteins chemistry, Nuclear Proteins metabolism, Ribonucleoproteins, Small Nucleolar metabolism, Saccharomyces cerevisiae chemistry, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism, Saccharomyces cerevisiae Proteins chemistry, Saccharomyces cerevisiae Proteins metabolism
- Abstract
SHQ1 is an essential assembly factor for H/ACA ribonucleoproteins (RNPs) required for ribosome biogenesis, pre-mRNA splicing, and telomere maintenance. SHQ1 binds dyskerin/NAP57, the catalytic subunit of human H/ACA RNPs, and this interaction is modulated by mutations causing X-linked dyskeratosis congenita. We report the crystal structure of the C-terminal domain of yeast SHQ1, Shq1p, and its complex with yeast dyskerin/NAP57, Cbf5p, lacking its catalytic domain. The C-terminal domain of Shq1p interacts with the RNA-binding domain of Cbf5p and, through structural mimicry, uses the RNA-protein-binding sites to achieve a specific protein-protein interface. We propose that Shq1p operates as a Cbf5p chaperone during RNP assembly by acting as an RNA placeholder, thereby preventing Cbf5p from nonspecific RNA binding before association with an H/ACA RNA and the other core RNP proteins.
- Published
- 2011
- Full Text
- View/download PDF
20. A dyskerin motif reactivates telomerase activity in X-linked dyskeratosis congenita and in telomerase-deficient human cells.
- Author
-
Machado-Pinilla R, Sánchez-Pérez I, Murguía JR, Sastre L, and Perona R
- Subjects
- Amino Acid Sequence, Animals, Cell Line, Cell Survival drug effects, Cisplatin pharmacology, Drug Resistance drug effects, Enzyme Activation drug effects, Enzyme Inhibitors pharmacology, Humans, Mice, Molecular Sequence Data, Promoter Regions, Genetic, Protein Structure, Tertiary, Proto-Oncogene Proteins c-myc genetics, RNA metabolism, Structure-Activity Relationship, Telomerase antagonists & inhibitors, Amino Acid Motifs, Cell Cycle Proteins chemistry, Dyskeratosis Congenita enzymology, Nuclear Proteins chemistry, Peptide Fragments chemistry, Telomerase deficiency, Telomerase metabolism
- Abstract
Dyskerin gene is mutated in patients with X-linked dyskeratosis congenita (X-DC), which results in greatly reduced levels of telomerase activity. A genetic suppressor element (GSE) termed GSE24-2 has been isolated in a screening for cisplatin resistance. GSE24-2-expressing cells presented impaired telomerase inhibition following in vitro exposure to chemotherapies, such as cisplatin, or telomerase inhibitors. The promoter of the telomerase component hTERT was constitutively activated in GSE24-2 cells in a c-myc expression-dependent manner. Deletion analyses and mutagenesis of the human c-myc promoter demonstrated that the target sequence for activation was the nuclease hypersensitive element-III (NHEIII) site located upstream to the P1 region of the promoter. Further, expression of GSE24-2 in cell lines derived from patients with X-DC and in VA13 cells induced increased hTERT RNA and hTR levels and recovery of telomerase activity. Finally, expression of GSE24-2 was able to rescue X-DC fibroblasts from premature senescence. These data demonstrate that this domain of dyskerin plays an important role in telomerase maintenance following cell insults such as cisplatin treatment, and in telomerase-defective cells in patients with X-DC. The expression of this dyskerin fragment has a dominant function in X-DC cells and could provide the basis for a therapeutic approach to this disease.
- Published
- 2008
- Full Text
- View/download PDF
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