Search results for " RNA"

Forced Retroevolution of an RNA Bacteriophage

2000

AbstractThe operator hairpin ahead of the replicase gene in RNA bacteriophage MS2 contains overlapping signals for binding the coat protein and ribosomes. Coat protein binding inhibits further translation of the gene and forms the first step in capsid formation. The hairpin sequence was partially randomized to assess the importance of this structure element for the bacteriophage and to monitor alternative solutions that would evolve on the passaging of mutant phages. The evolutionary reconstruction of the operator failed in the majority of mutants. Instead, a poor imitation developed containing only some of the recognition signals for the coat protein. Three mutants were of particular inter…

The primary structure of cytoplasmic initiator tRNAMetfromSchizosaccharomyces pombe

1993

Differential annotation of tRNA genes with anticodon CAT in bacterial genomes.

2006

We have developed three strategies to discriminate among the three types of tRNA genes with anticodon CAT (tRNA(Ile), elongator tRNA(Met) and initiator tRNA(fMet)) in bacterial genomes. With these strategies, we have classified the tRNA genes from 234 bacterial and several organellar genomes. These sequences, in an aligned or unaligned format, may be used for the identification and annotation of tRNA (CAT) genes in other genomes. The first strategy is based on the position of the problem sequences in a phenogram (a tree-like network), the second on the minimum average number of differences against the tRNA sequences of the three types and the third on the search for the highest score value …

Abstract 4479: Unveiling the relationship between the SWI/SNF chromatin remodeling complex and noncoding RNAs

2016

Abstract Chromatin remodeling complexes are crucial for the viability of the cells due to their role in regulating interactions between DNA and histones and, therefore, modifying the accessibility of the genetic information to the transcriptional machinery. This relevance can also been seen in the SWI/SNF complex that has been associated with cancer in the last deep-sequencing efforts on tumoral genomes. BRG1 is the helicase/ATPase catalytic subunit of the SWI/SNF complex and it is frequently lost in NSCLC cell lines with a high mutation rate. In primary tumors, the loss of expression of BRG1 is also frequent, however it cannot be explained by mutations or by promoter hypermethylation. In t…

On the Specificity of PCR Detection of Listeria monocytogenes in Food: a Comparison of Published Primers

2002

A total of nine pairs of primers, seven previously published and two newly developed, have been assayed for PCR detection of Listeria monocytogenes in food. They have been tested for specificity on a total of 72 strains including reference and food isolates belonging to L. monocytogenes and other species in the genus. First of all, a polyphasic approach has been carried out in order to establish a reference strain collection. They were biochemically and genetically characterized by API-Lis and randomly amplified polymorphic DNA PCR (RAPD-PCR), respectively. Random amplification of DNA was performed with M13, T7 and T3 universal primers and a data bank was created to compile the RAPD pattern…

Piwi proteins and piRNAs in mammalian oocytes and early embryos: From sample to sequence

2015

AbstractThe role of the Piwi/piRNA pathway during mammalian oogenesis has remained enigmatic thus far, especially since experiments with Piwi knockout mice did not reveal any phenotypic defects in female individuals. This is in striking contrast with results obtained from other species including flies and zebrafish. In mouse oocytes, however, only low levels of piRNAs are found and they are not required for their function. We recently demonstrated dynamic expression of PIWIL1, PIWIL2, and PIWIL3 during mammalian oogenesis and early embryogenesis. In addition, small RNA analysis of human, crab-eating macaque and cattle revealed that piRNAs are also expressed in the female germline and closel…

Cloning of Hsp70 genes from the marine sponges Sycon raphanus (Calcarea) and Rhabdocalyptus dawsoni (Hexactinellida). An approach to solve the phylog…

1997

The phylogenetic relationships among the three classes of the Porifera—Demospongiae, Calcarea and Hexactinellida—are still unresolved, despite the use of molecular analyses of rRNA. To determine whether phylogenetic resolution of these classes is possible based on genes coding for specific proteins, in the present study the genes for the 70 kDa heat shock protein [Hsp70] were isolated fromRhabdocalyptus dawsoni[Hexactinellida] and fromSycon raphanus[Calcarea], and compared to that previously isolated from the demospongeGeodia cydonium. The gene fromR. dawsoniis 2021 bp long and encodes a predicted Hsp70 of Mr77,697; the protein comprises the characteristic sites of eukaryotic, cytoplasmic H…

The role of telomeres in predicting individual radiosensitivity of patients with cancer in the era of personalized radiotherapy.

2014

Radiotherapy plays a key role in cancer treatments, but tumor cell death differs from one tumor to another. The response of patients to radiotherapy varies considerably and adverse side effects are difficult to prevent. The mechanisms involved in the heterogeneity of this response are not well understood. In order to enhance the efficacy and safety of radiotherapy, it is important to identify subpopulations most at risk of developing a late adverse response to radiotherapy. Telomeres are composed of multiple repeats of a unique sequence of nucleotides forming a TTAGGG pattern. They protect chromosomes from end-to-end fusion and maintain genomic stability. Telomeres have been shown to be ext…

Analysis of tombusvirus revertants to identify essential amino acid residues within RNA-dependent RNA polymerase motifs

2005

The RNA-dependent RNA polymerase (RdRp) of Tomato bushy stunt virus (TBSV) contains an arginine- and proline-rich (RPR) motif. This motif functions as an RNA-binding domain and is essential for tombusvirus replication. A mutant carrying three arginine substitutions in this motif rendered the virus unable to replicate in Nicotiana benthamiana plants and protoplasts. When the replicase function was provided in trans, by expressing the TBSV RdRp in N. benthamiana plants, an infectious variant could be isolated. Sequence analysis showed that only the substituted glycine residue (position 216) had reverted to arginine; all other substitutions remained unchanged. This finding suggested that stron…

2015

Piwi-interacting (pi-) RNAs guide germline-expressed Piwi proteins in order to suppress the activity of transposable elements (TEs). But notably, the majority of pachytene piRNAs in mammalian testes is not related to TEs. This raises the question of whether the Piwi/piRNA pathway exerts functions beyond TE silencing. Although gene-derived piRNAs were described many times, a possible gene-regulatory function was doubted due to the absence of antisense piRNAs. Here we sequenced and analyzed piRNAs expressed in the adult testis of the pig, as this taxon possesses the full set of mammalian Piwi paralogs while their spermatozoa are marked by an extreme fitness due to selective breeding. We provi…