Recombination, Genetic

Publication Title: 
PloS One

Borage (Borago officinalis L.) seed oil has been used as a treatment for various degenerative diseases. Many useful properties of this oil are attributed to its high gamma linolenic acid content (GLA, 18:3 ?-6). The purpose of this study was to demonstrate the safety and suitability of the use of borage seed oil, along with one of its active components, GLA, with respect to DNA integrity, and to establish possible in vivo toxic and in vitro cytotoxic effects.

Author(s): 
Tasset-Cuevas, Inmaculada
Fern·ndez-Bedmar, Zahira
Lozano-Baena, MarÌa Dolores
Campos-S·nchez, Juan
de Haro-BailÛn, Antonio
MuÒoz-Serrano, AndrÈs
Alonso-Moraga, Angeles
Publication Title: 
Nature

In diverse organisms, calorie restriction slows the pace of ageing and increases maximum lifespan. In the budding yeast Saccharomyces cerevisiae, calorie restriction extends lifespan by increasing the activity of Sir2 (ref. 1), a member of the conserved sirtuin family of NAD(+)-dependent protein deacetylases. Included in this family are SIR-2.1, a Caenorhabditis elegans enzyme that regulates lifespan, and SIRT1, a human deacetylase that promotes cell survival by negatively regulating the p53 tumour suppressor.

Author(s): 
Howitz, Konrad T.
Bitterman, Kevin J.
Cohen, Haim Y.
Lamming, Dudley W.
Lavu, Siva
Wood, Jason G.
Zipkin, Robert E.
Chung, Phuong
Kisielewski, Anne
Zhang, Li-Li
Scherer, Brandy
Sinclair, David A.
Publication Title: 
Methods in Molecular Biology (Clifton, N.J.)

The diet known as caloric restriction (CR) has been known for 70 yr to extend the life span of rodents (1). CR can also extend life span in a broad range of other species as well, from unicellular organisms (2,3), to invertebrates (4) and most likely primates, as well (5). The budding yeast Saccharomyces cerevisiae is a useful model for the study of pathways that determine life span in response to dietary intake.

Author(s): 
Medvedik, Oliver
Sinclair, David A.
Publication Title: 
The Journal of Cell Biology

Werner and Bloom syndromes are human diseases characterized by premature age-related defects including elevated cancer incidence. Using a novel Saccharomyces cerevisiae model system for aging and cancer, we show that cells lacking the RecQ helicase SGS1 (WRN and BLM homologue) undergo premature age-related changes, including reduced life span under stress and calorie restriction (CR), G1 arrest defects, dedifferentiation, elevated recombination errors, and age-dependent increase in DNA mutations.

Author(s): 
Madia, Federica
Gattazzo, Cristina
Wei, Min
Fabrizio, Paola
Burhans, William C.
Weinberger, Martin
Galbani, Abdoulaye
Smith, Jesse R.
Nguyen, Christopher
Huey, Selina
Comai, Lucio
Longo, Valter D.
Publication Title: 
Cell

Developmentally controlled genomic deletion-ligations occur during ciliate macronuclear differentiation. We have identified a novel activity in Tetrahymena cell-free extracts that efficiently catalyzes a specific set of intramolecular DNA deletion-ligation reactions. When synthetic DNA oligonucleotide substrates were used, all the deletion-ligation products resembled those formed in vivo in that they resulted from deletions between pairs of short direct repeats. The reaction is ATP-dependent, salt-sensitive, and strongly influenced by the oligonucleotide substrate sequence.

Author(s): 
Robinson, E. K.
Cohen, P. D.
Blackburn, E. H.
Publication Title: 
Genetics

The micronuclear genome of Tetrahymena thermophila contains Tel-1 elements that structurally resemble transposons. Here we present molecular evidence that Tel-1 transposon-like elements are mobile. The arrangements of Tel-1 elements in the micronuclear genomes of several T. thermophila strains and cell lines were assayed by Southern blotting. The molecular evidence for Tel-1 transposition is most striking in strains that have undergone unusual laboratory-induced meioses.

Author(s): 
Wyman, C.
Blackburn, E. H.
Publication Title: 
Proceedings of the National Academy of Sciences of the United States of America

We transformed the ciliate Tetrahymena thermophila by microinjection of circular plasmids containing the ribosomal RNA gene (rDNA). In the somatic macronucleus of Tetrahymena, the rDNA is in the form of linear palindromic molecules. The rDNA molecules from the C3 strain have a replication advantage over rDNA from both B strain and the C3 rDNA mutant rmm1. We constructed two circular plasmids carrying replication origin sequences from C3 rDNA and a point mutation (Pmr) in the 17S rRNA gene that confers resistance to the antibiotic paromomycin.

Author(s): 
Yu, G. L.
Hasson, M.
Blackburn, E. H.
Publication Title: 
Genetics

The micronuclear genome of Tetrahymena thermophila contains Tel-1 elements that structurally resemble transposons. Here we present molecular evidence that Tel-1 transposon-like elements are mobile. The arrangements of Tel-1 elements in the micronuclear genomes of several T. thermophila strains and cell lines were assayed by Southern blotting. The molecular evidence for Tel-1 transposition is most striking in strains that have undergone unusual laboratory-induced meioses.

Author(s): 
Wyman, C.
Blackburn, E. H.
Publication Title: 
Genes & Development

Deletion of the telomerase RNA gene (TER1) in the yeast Kluyveromyces lactis results in gradual loss of telomeric repeats and progressively declining cell growth capability (growth senescence). We show that this initial growth senescence is characterized by abnormally large, defectively dividing cells and is delayed when cells initially contain elongated telomeres. However, cells that survive the initial catastrophic senescence emerge relatively frequently, and their subsequent growth without telomerase is surprisingly efficient.

Author(s): 
McEachern, M. J.
Blackburn, E. H.
Publication Title: 
Molecular and Cellular Biology

The macronuclear rRNA genes (rDNA) in the ciliate Tetrahymena thermophila are normally palindromic linear replicons, containing two copies of the replication origin region in inverted orientation. A circular plasmid containing a single Tetrahymena rRNA gene (one half palindrome) joined to a tandem repeat of a 1.9-kilobase (kb) rDNA segment encompassing the rDNA replication origin and known replication control elements was used to transform Tetrahymena macronuclei by microinjection.

Author(s): 
Yu, G. L.
Blackburn, E. H.

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