997 resultados para NETTRA-G4.


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The significance of G-quadruplexes and the helicases that resolve G4 structures in prokaryotes is poorly understood. The Mycobacterium tuberculosis genome is GC-rich and contains >10,000 sequences that have the potential to form G4 structures. In Escherichia coli, RecQ helicase unwinds G4 structures. However, RecQ is absent in M. tuberculosis, and the helicase that participates in G4 resolution in M. tuberculosis is obscure. Here, we show that M. tuberculosis DinG (MtDinG) exhibits high affinity for ssDNA and ssDNA translocation with a 5' -> 3' polarity. Interestingly, MtDinG unwinds overhangs, flap structures, and forked duplexes but fails to unwind linear duplex DNA. Our data with DNase I footprinting provide mechanistic insights and suggest that MtDinG is a 5' -> 3' polarity helicase. Notably, in contrast to E. coli DinG, MtDinG catalyzes unwinding of replication fork and Holliday junction structures. Strikingly, we find that MtDinG resolves intermolecular G4 structures. These data suggest that MtDinG is a multifunctional structure-specific helicase that unwinds model structures of DNA replication, repair, and recombination as well as G4 structures. We finally demonstrate that promoter sequences of M. tuberculosis PE_PGRS2, mce1R, and moeB1 genes contain G4 structures, implying that G4 structures may regulate gene expression in M. tuberculosis. We discuss these data and implicate targeting G4 structures and DinG helicase in M. tuberculosis could be a novel therapeutic strategy for culminating the infection with this pathogen.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Rotavirus is the most common etiological cause of acute viral gastroenteritis in infants and young children worldwide, yet its role in the adult population is less well understood. We have recently identified rotavirus as the causative agent of severe diarrhea in adults, specifically in two gastroenteritis outbreaks in separate care for the elderly homes. Strain typing has shown the continued presence of P[8]G1, the emergence of P[8]G9, and the reemergence of P[8]G4. A total of 26 community cases and 6 outbreak cases of rotavirus infection, positive via a molecular screening assay, were subsequently amplified using VP4 and VP7 specific primers (Con2/Con3 and 1A/1B primer sets, respectively). The age range of patients investigated was from

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The current morphological classification of the Demospongiae G4 clade was tested using large subunit ribosomal RNA (LSU rRNA) sequences from 119 taxa. Fifty-three mitochondrial cytochrome oxidase 1 (CO1) barcoding sequences were also analysed to test whether the 28S phylogeny could be recovered using an independent gene. This is the largest and most comprehensive study of the Demospongiae G4 clade. The 28S and CO1 genetrees result in congruent clades but conflict with the current morphological classification. The results confirm the polyphyly of Halichondrida, Hadromerida, Dictyonellidae, Axinellidae and Poecilosclerida and show that several of the characters used in morphological classifications are homoplasious. Robust clades are clearly shown and a new hypothesis for relationships of taxa allocated to G4 is proposed. (C) 2011 Elsevier Inc. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

El 11 de julio de 2005 el grupo denominado G4 -Alemania, Japón, India y Brasil- presenta a la Asamblea General una propuesta de ampliación del Consejo de Seguridad de Naciones Unidas. A partir de lo anterior se analiza el panorama de Brasil en el G4 y su pretensión de asumir un puesto preponderante en el principal órgano de Naciones Unidas, como representante de América Latina.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The yeast gene KEM1 (also named SEP1/DST2/XRN1/RAR5) produces a G4-DNA-dependent nuclease that binds to G4 tetraplex DNA structure and cuts in a single-stranded region 5' to the G4 structure. G4-DNA generated from yeast telomeric oligonucleotides competitively inhibits the cleavage reaction, suggesting that this enzyme may interact with yeast telomeres in vivo. Homozygous deletions of the KEM1 gene in yeast block meiosis at the pachytene stage, which is consistent with the hypothesis that G4 tetraplex DNA may be involved in homologous chromosome pairing during meiosis. We conjectured that the mitotic defects of kem1/sep1 mutant cells, such as a higher chromosome loss rate, are also due to failure in processing G4-DNA, especially at telomeres. Here we report two phenotypes associated with a kem1-null allele, cellular senescence and telomere shortening, that provide genetic evidence that G4 tetraplex DNA may play a role in telomere functioning. In addition, our results reveal that chromosome ends in the same cells behave differently in a fashion dependent on the KEM1 gene product.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bibliography: p. 209-212.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

"UILU-ENG 77 1743."

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thesis (M. S.)--University of Illinois at Urbana-Champaign.