The CCR4-NOT Complex Physically and Functionally Interacts with TRAMP and the Nuclear Exosome

BACKGROUND: Ccr4-Not is a highly conserved multi-protein complex consisting in yeast of 9 subunits, including Not5 and the major yeast deadenylase Ccr4. It has been connected functionally in the nucleus to transcription by RNA polymerase II and in the cytoplasm to mRNA degradation. However, there has been no evidence so far that this complex is important for RNA degradation in the nucleus. METHODOLOGY/PRINCIPAL FINDINGS: In this work we point to a new role for the Ccr4-Not complex in nuclear RNA metabolism. We determine the importance of the Ccr4-Not complex for the levels of non-coding nuclear RNAs, such as mis-processed and polyadenylated snoRNAs, whose turnover depends upon the nuclear exosome and TRAMP. Consistently, mutation of both the Ccr4-Not complex and the nuclear exosome results in synthetic slow growth phenotypes. We demonstrate physical interactions between the Ccr4-Not complex and the exosome. First, Not5 co-purifies with the exosome. Second, several exosome subunits co-purify with the Ccr4-Not complex. Third, the Ccr4-Not complex is important for the integrity of large exosome-containing complexes. Finally, we reveal a connection between the Ccr4-Not complex and TRAMP through the association of the Mtr4 helicase with the Ccr4-Not complex and the importance of specific subunits of Ccr4-Not for the association of Mtr4 with the nuclear exosome subunit Rrp6. CONCLUSIONS/SIGNIFICANCE: We propose a model in which the Ccr4-Not complex may provide a platform contributing to dynamic interactions between the nuclear exosome and its co-factor TRAMP. Our findings connect for the first time the different players involved in nuclear and cytoplasmic RNA degradation

Constitutive Activation of PrfA Tilts the Balance of Listeria monocytogenes Fitness Towards Life within the Host versus Environmental Survival

PrfA is a key regulator of Listeria monocytogenes pathogenesis and induces the expression of multiple virulence factors within the infected host. PrfA is post-translationally regulated such that the protein becomes activated upon bacterial entry into the cell cytosol. The signal that triggers PrfA activation remains unknown, however mutations have been identified (prfA* mutations) that lock the protein into a high activity state. In this report we examine the consequences of constitutive PrfA activation on L. monocytogenes fitness both in vitro and in vivo. Whereas prfA* mutants were hyper-virulent during animal infection, the mutants were compromised for fitness in broth culture and under conditions of stress. Broth culture prfA*-associated fitness defects were alleviated when glycerol was provided as the principal carbon source; under these conditions prfA* mutants exhibited a competitive advantage over wild type strains. Glycerol and other three carbon sugars have been reported to serve as primary carbon sources for L. monocytogenes during cytosolic growth, thus prfA* mutants are metabolically-primed for replication within eukaryotic cells. These results indicate the critical need for environment-appropriate regulation of PrfA activity to enable L. monocytogenes to optimize bacterial fitness inside and outside of host cells

The Core Value Compass: visually evaluating the goodness of brands that do good

yesBrands that do good for the society as well as for themselves are motivated by the core values they espouse, which necessitates a better understanding of what qualities a true core value must possess. The inherent tension within brands that do good, between commercial interests to increase competitiveness, and societal interests that are closely linked to the brand’s authenticity, has largely been overlooked. Hence, we develop and demonstrate a relatively easy-to-apply visual tool for evaluating core values based on a set of ‘goodness’ criteria derived from extant theory. The Core Value Compass adopts a paradox-based, evolutionary perspective by incorporating the inherent tensions within true core values, and classifying them according to their temporal orientation. Thus, we contribute towards a better understanding of underlying tensions of core values and provide a practical tool that paves the way for improved, and indeed ethical, corporate branding strategies. Furthermore, we demonstrate the Compass’ application using the case of a public sector brand, which is a quintessential brand that does good. Therefore, we also contribute to the nascent theoretical discourse on public sector branding. This paper therefore adds to the notable attempts to bridge the gap between theory and practice in core values-based corporate branding

Does personality congruence explain luxury brand attachment? The results of an international research study

© 2020 Elsevier Inc. There is a general lack of clarity regarding measurement of the self-brand congruity construct, which also calls for cross-national validation. Although previous evidence suggests a positive relationship between self-brand congruity and consumer brand associations (brand attachment), this relationship requires a deeper investigation. This study tests and validates a personality congruence scale in the luxury sector on an international level. Based on a survey of nearly 1500 international luxury customers, it also measures the effect of congruence on brand attachment. The findings confirm that the personality congruence structure is based on five dimensions: prestige, emotion, trust, anxiety, and order. The results highlight the personality congruence effect and its influence on brand attachment. Finally, similarities and differences across countries are detected in the personality congruence and brand attachment relationship. Theoretical and managerial implications are also discussed. This study contributes to the literature on brand personality congruence and its impact on brand attachment in the luxury context