Gene Deletion

Publication Title: 
Nature

Calorie restriction extends lifespan in organisms ranging from yeast to mammals. In yeast, the SIR2 gene mediates the life-extending effects of calorie restriction. Here we show that the mammalian SIR2 orthologue, Sirt1 (sirtuin 1), activates a critical component of calorie restriction in mammals; that is, fat mobilization in white adipocytes. Upon food withdrawal Sirt1 protein binds to and represses genes controlled by the fat regulator PPAR-gamma (peroxisome proliferator-activated receptor-gamma), including genes mediating fat storage.

Author(s): 
Picard, FrÈdÈric
Kurtev, Martin
Chung, Namjin
Topark-Ngarm, Acharawan
Senawong, Thanaset
Machado De Oliveira, Rita
Leid, Mark
McBurney, Michael W.
Guarente, Leonard
Publication Title: 
Experimental Gerontology

The absence of mtDNA in rho0 yeast cells affects both respiration and mitochondrial-nuclear communication (e.g., retrograde regulation, intergenomic signaling, or pleiotropic drug resistance). Previously, it has been reported that some rho0 strains have increased replicative lifespans, attributable to the lack of respiration and retrograde regulation.

Author(s): 
Woo, Dong Kyun
Poyton, Robert O.
Publication Title: 
Molecular and Cellular Biology

The ubiquitin ligase CHIP (carboxyl terminus of Hsp70-interacting protein) regulates protein quality control, and CHIP deletion accelerates aging and reduces the life span in mice. Here, we reveal a mechanism for CHIP's influence on longevity by demonstrating that CHIP stabilizes the sirtuin family member SirT6, a lysine deacetylase/ADP ribosylase involved in DNA repair, metabolism, and longevity.

Author(s): 
Ronnebaum, Sarah M.
Wu, Yaxu
McDonough, Holly
Patterson, Cam
Publication Title: 
Nature

Calorie restriction extends lifespan in organisms ranging from yeast to mammals. In yeast, the SIR2 gene mediates the life-extending effects of calorie restriction. Here we show that the mammalian SIR2 orthologue, Sirt1 (sirtuin 1), activates a critical component of calorie restriction in mammals; that is, fat mobilization in white adipocytes. Upon food withdrawal Sirt1 protein binds to and represses genes controlled by the fat regulator PPAR-gamma (peroxisome proliferator-activated receptor-gamma), including genes mediating fat storage.

Author(s): 
Picard, FrÈdÈric
Kurtev, Martin
Chung, Namjin
Topark-Ngarm, Acharawan
Senawong, Thanaset
Machado De Oliveira, Rita
Leid, Mark
McBurney, Michael W.
Guarente, Leonard
Publication Title: 
Science of aging knowledge environment: SAGE KE

What's left to learn about aging? The burning question for many researchers is whether life-stretching pathways and genes from model organisms boost human life span. Researchers might be able to track down additional genes and pathways that adjust longevity by studying a broader range of organisms or by tracking the evolution of genes that promote aging. An alternative way to extend our lives might be to identify the genes behind late-life killers such as heart disease and diabetes.

Author(s): 
Leslie, Mitch
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 Metabolism

Iron regulatory proteins (Irps) 1 and 2 posttranscriptionally control the expression of transcripts that contain iron-responsive element (IRE) sequences, including ferritin, ferroportin, transferrin receptor, and hypoxia-inducible factor 2? (HIF2?). We report here that mice with targeted deletion of Irp1 developed pulmonary hypertension and polycythemia that was exacerbated by a low-iron diet. Hematocrits increased to 65% in iron-starved mice, and many polycythemic mice died of abdominal hemorrhages. Irp1 deletion enhanced HIF2?

Author(s): 
Ghosh, Manik C.
Zhang, De-Liang
Jeong, Suh Young
Kovtunovych, Gennadiy
Ollivierre-Wilson, Hayden
Noguchi, Audrey
Tu, Tiffany
Senecal, Thomas
Robinson, Gabrielle
Crooks, Daniel R.
Tong, Wing-Hang
Ramaswamy, Kavitha
Singh, Anamika
Graham, Brian B.
Tuder, Rubin M.
Yu, Zu-Xi
Eckhaus, Michael
Lee, Jaekwon
Springer, Danielle A.
Rouault, Tracey A.
Publication Title: 
Molecular Biology of the Cell

Mutation of the template region in the RNA component of telomerase can cause incorporation of mutant DNA sequences at telomeres. We made all 63 mutant sequence combinations at template positions 474-476 of the yeast telomerase RNA, TLC1. Mutants contained faithfully incorporated template mutations, as well as misincorporated sequences in telomeres, a phenotype not previously reported for Saccharomyces cerevisiae telomerase template mutants. Although growth rates and telomere profiles varied widely among the tlc1 mutants, chromosome separation and segregation were always aberrant.

Author(s): 
Lin, Jue
Smith, Dana L.
Blackburn, Elizabeth H.
Publication Title: 
Cancer Research

Human telomerase reverse transcriptase (hTERT; the catalytic protein subunit of telomerase) is subjected to numerous alternative splicing events, but the regulation and function of these splice variants is obscure. Full-length hTERT includes conserved domains that encode reverse transcriptase activity, RNA binding, and other functions. The major splice variant termed ?+?- or ?-deletion is highly expressed in stem and cancer cells, where it codes for a truncated protein lacking most of the reverse transcriptase domain but retaining the known RNA-binding motifs.

Author(s): 
Listerman, Imke
Sun, Jie
Gazzaniga, Francesca S.
Lukas, Jason L.
Blackburn, Elizabeth 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.

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