Home  About us  Contact
 

Information Regulator (information + regulator)

Distribution by Scientific Domains
Life Sciences60%

Kinds of Information Regulator

  • silent information regulator
    		•

    Selected Abstracts

    Calorie restriction effects on silencing and recombination at the yeast rDNA

    AGING CELL, Issue 6 2009
    Daniel L. Smith Jr
    Summary Aging research has developed rapidly over the past decade, identifying individual genes and molecular mechanisms of the aging process through the use of model organisms and high throughput technologies. Calorie restriction (CR) is the most widely researched environmental manipulation that extends lifespan. Activation of the NAD+ -dependent protein deacetylase Sir2 (Silent Information Regulator 2) has been proposed to mediate the beneficial effects of CR in the budding yeast Saccharomyces cerevisiae, as well as other organisms. Here, we show that in contrast to previous reports, Sir2 is not stimulated by CR to strengthen silencing of multiple reporter genes in the rDNA of S. cerevisiae. CR does modestly reduce the frequency of rDNA recombination, although in a SIR2 -independent manner. CR-mediated repression of rDNA recombination also does not correlate with the silencing of Pol II-transcribed noncoding RNAs derived from the rDNA intergenic spacer, suggesting that additional silencing-independent pathways function in lifespan regulation. [source]

    Analysis of Sir2E in the cellular slime mold Dictyostelium discoideum: Cellular localization, spatial expression and overexpression

    DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 8 2008
    Takahiro Katayama
    It has been reported that Dictyostelium discoideum encodes four silent information regulator 2 (Sir2) proteins (Sir2A,D) showing sequence similarity to human homologues of Sir2 (SIRT1,3). Further screening in a database revealed that D. discoideum encodes an additional Sir2 homologue (Sir2E). The amino acid sequence of Sir2E is not similar to those of SIRTs but is similar to those of proteins encoded by Giardia lamblia, Cryptosporidium hominis and Cryptosporidium parvum. Fluorescence of Sir2E-green fluorescent protein fusion protein was detected in the D. discoideum nucleus, indicating that Sir2E is a nuclear localizing protein. Reverse transcription,polymerase chain reaction and whole-mount in situ hybridization analyses showed that D. discoideum expressed sir2E in amoebae in the growth phase and in prestalk cells in the developmental phase. D. discoideum overexpressing sir2E grew faster than the wild type. These results indicate that Sir2E plays important roles both in the growth phase and developmental phase of D. discoideum. [source]

    Silent information regulator, Sirtuin 1, and age-related diseases

    GERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 1 2009
    Li Zeng
    Sirtuin 1 (SIRT1), a member of the silent information regulator 2 in mammals, has recently been found to be involved in age-related diseases, such as cancer, metabolic diseases, cardiovascular disease, neurodegenerative diseases, osteoporosis and chronic obstructive pulmonary disease (COPD), mainly through deacetylation of substrates such as p53, forkhead box class O, peroxisome proliferator activated receptor , co-activator 1,, and nuclear factor-,B. It is widely reported that SIRT1 can promote not only carcinogenesis but also metastasis and insulin resistance, andhave beneficial effects in metabolic diseases, mediate high-density lipoprotein synthesis and regulate endothelial nitric oxide to protect against cardiovascular disease, have a cardioprotective role in heart failure, protect against neurodegenerative pathological changes, promote osteoblast differentiation, and also play a pivotal role as an anti-inflammatory mediator in COPD. However, there are controversial results suggesting that SIRT1 has an effect in protecting against DNA damage and accumulation of mutations, and preventing tumorigenesis. In addition, a high level of SIRT1 can induce cardiomyopathy and even heart failure. This article reviews recent developments relating to these issues. [source]

    Neuronal protection by sirtuins in Alzheimer's disease

    JOURNAL OF NEUROCHEMISTRY, Issue 2 2006
    Thimmappa S. Anekonda
    Abstract Silent information regulator 2, a member of NAD+ -dependent histone deacetylase in yeast, and its homologs in mice and humans, participate in numerous important cell functions, including cell protection and cell cycle regulation. The sirtuin family members are highly conserved evolutionarily, and are predicted to have a role in cell survival. The science of sirtuins is an emerging field and is expected to contribute significantly to the role of sirtuins in healthy aging in humans. The role of sirtuins in neuronal protection has been studied in lower organisms, such as yeast, worms, flies and rodents. Both yeast Sir2 and mammalian sirtuin proteins are up-regulated under calorie-restricted and resveratrol treatments. Increased sirtuin expression protects cells from various insults. Caloric restriction and antioxidant treatments have shown useful effects in mouse models of aging and Alzheimer's disease (AD) and in limited human AD clinical trials. The role sirtuins may play in modifying and protecting neurons in patients with neurodegenerative diseases is still unknown. However, a recent report of Huntington's disease revealed that Sirtuin protects neurons in a Huntington's disease mouse model, suggesting that sirtuins may protect neurons in patients with neurodegenerative diseases, such as AD. In this review, we discuss the possible mechanisms of sirtuins involved in neuronal protection and the potential therapeutic value of sirtuins in healthy aging and AD. [source]