140 research outputs found

    Regulation of Transcriptional Activators by DNA-Binding Domain Ubiquitination

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    Ubiquitin is a key component of the regulatory network that maintains gene expression in eukaryotes, yet the molecular mechanism(s) by which non-degradative ubiquitination modulates transcriptional activator (TA) function is unknown. Here endogenous p53, a stress-activated transcription factor required to maintain health, is stably monoubiquitinated, following pathway activation by IR or Nutlin-3 and localized to the nucleus where it becomes tightly associated with chromatin. Comparative structure–function analysis and in silico modelling demonstrate a direct role for DNA-binding domain (DBD) monoubiquitination in TA activation. When attached to the DBD of either p53, or a second TA IRF-1, ubiquitin is orientated towards, and makes contact with, the DNA. The contact is made between a predominantly cationic surface on ubiquitin and the anionic DNA. Our data demonstrate an unexpected role for ubiquitin in the mechanism of TA-activity enhancement and provides insight into a new level of transcriptional regulation

    A new, large-bodied omnivorous bat (Noctilionoidea: Mystacinidae) reveals lost morphological and ecological diversity since the Miocene in New Zealand

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    A new genus and species of fossil bat is described from New Zealand's only pre-Pleistocene Cenozoic terrestrial fauna, the early Miocene St Bathans Fauna of Central Otago, South Island. Bayesian total evidence phylogenetic analysis places this new Southern Hemisphere taxon among the burrowing bats (mystacinids) of New Zealand and Australia, although its lower dentition also resembles Africa's endemic sucker-footed bats (myzopodids). As the first new bat genus to be added to New Zealand's fauna in more than 150 years, it provides new insight into the original diversity of chiropterans in Australasia. It also underscores the significant decline in morphological diversity that has taken place in the highly distinctive, semi-terrestrial bat family Mystacinidae since the Miocene. This bat was relatively large, with an estimated body mass of ~40 g, and its dentition suggests it had an omnivorous diet. Its striking dental autapomorphies, including development of a large hypocone, signal a shift of diet compared with other mystacinids, and may provide evidence of an adaptive radiation in feeding strategy in this group of noctilionoid bats

    Testosterone levels are negatively associated with childlessness in males, but positively related to offspring count in fathers

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    Variation in testosterone (T) is thought to affect the allocation of effort between reproductive and parenting strategies. Here, using a large sample of elderly American men (n = 754) and women (n = 669) we examined the relationship between T and self-reported parenthood, as well as the relationship between T and number of reported children. Results supported previous findings from the literature, showing that fathers had lower T levels than men who report no children. Furthermore, we found that among fathers T levels were positively associated with the number of children a man reports close to the end of his lifespan. Results were maintained when controlling for a number of relevant factors such as time of T sampling, participant age, educational attainment, BMI, marital status and reported number of sex partners. In contrast, T was not associated with either motherhood or the number of children women had, suggesting that, at least in this sample, T does not influence the allocation of effort between reproductive and parenting strategies among women. Findings from this study contribute to the growing body of literature suggesting that, among men, pair bonding and paternal care are associated with lower T levels, while searching and acquiring sex partners is associated with higher T levels.27 Jun 2013: Pollet TV, Cobey KD, van der Meij L (2013) Correction: Testosterone Levels Are Negatively Associated with Childlessness in Males, but Positively Related to Offspring Count in Fathers. PLoS ONE 8(6): 10.1371/annotation/bccccb7e-48a7-4594-b3e6-ce8c9d2489a2

    Alcohol use and misuse: What are the contributions of occupation and work organization conditions?

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    <p>Abstract</p> <p>Background</p> <p>This research examines the specific contribution of occupation and work organization conditions to alcohol use and misuse. It is based on a social-action model that takes into account agent personality, structures of daily life, and macro social structures.</p> <p>Methods</p> <p>Data come from a representative sample of 10,155 workers in Quebec, Canada. Multinomial regression models corrected for sample design effect have been used to predict low-risk and high-risk drinking compared to non-drinkers. The contribution of occupation and work organization conditions (skill used, decision authority, physical and psychological demands, hours worked, irregular work schedule, harassment, unionization, job insecurity, performance pay, prestige) have been adjusted for family situation, social network outside the workplace, and individual characteristics.</p> <p>Results</p> <p>Compared to non-qualified blue-collars, both low-risk and high-risk drinking are associated with qualified blue-collars, semi-qualified white-collars, and middle managers; high-risk drinking is associated with upper managers. For constraints-resources related to work organization conditions, only workplace harassment is an important determinant of both low-risk and high-risk drinking, but it is modestly moderated by occupation. Family situation, social support outside work, and personal characteristics of individuals are also associated with alcohol use and misuse. Non-work factors mediated/suppressed the role of occupation and work organization conditions.</p> <p>Conclusion</p> <p>Occupation and workplace harassment are important factors associated with alcohol use and misuse. The results support the theoretical model conceptualizing alcohol use and misuse as being the product of stress caused by constraints and resources brought to bear simultaneously by agent personality, structures of daily life, and macro social structures. Occupational alcohol researchers must expand their theoretical perspectives to avoid erroneous conclusions about the specific role of the workplace.</p

    Histone deacetylase inhibitors: potential targets responsible for their anti-cancer effect

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    The histone deacetylase inhibitors (HDACi) have demonstrated anticancer efficacy across a range of malignancies, most impressively in the hematological cancers. It is uncertain whether this clinical efficacy is attributable predominantly to their ability to induce apoptosis and differentiation in the cancer cell, or to their ability to prime the cell to other pro-death stimuli such as those from the immune system. HDACi-induced apoptosis occurs through altered expression of genes encoding proteins in both intrinsic and extrinsic apoptotic pathways; through effects on the proteasome/aggresome systems; through the production of reactive oxygen species, possibly by directly inducing DNA damage; and through alterations in the tumor microenvironment. In addition HDACi increase the immunogenicity of tumor cells and modulate cytokine signaling and potentially T-cell polarization in ways that may contribute the anti-cancer effect in vivo. Here, we provide an overview of current thinking on the mechanisms of HDACi activity, with attention given to the hematological malignancies as well as scientific observations arising from the clinical trials. We also focus on the immune effects of these agents

    Reproductive constraints influence habitat accessibility, segregation, and preference of sympatric albatross species

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