Regulation of bistable ICEclc transfer in pseudomonas knackmussii B13

L'élément génétique intégratif et conjugatif auto-transférable de 103 kb qui se trouve dans le génome de Pseudomonas knackmussii B13 (ICEc/c) confère la capacité de dégrader le 3-chlorobenzoate et le 2-aminophénol. L'élément ICE c/c peut être transféré par conjugaison de la souche B13 à diverses bêta- et gamma- protéobactéries. Seule une sous-population de 3 à 5% des cellules transfère l'élément, les cellules dites "compétentes pour le transfert". L'acquisition de la compétence pour le transfert est vraisemblablement la conséquence d'une régulation bistable, conduisant une partie des cellules au transfert de l'élément ICE c/c tandis que, dans les autres, l'élément reste quiescent et ne se transfère pas. À ce jour, les mécanismes et les acteurs moléculaires qui régulent l'activation bistable de l'élément sont restés inconnus. Mon travail de doctorat visait à identifier les éléments bistables du régulon de la compétence pour le transfert et d'analyser les fondements moléculaires de la bistabilité de l'élément ICE c/c chez P. knackmussii. Le premier chapitre introduit le thème du transfert génétique horizontal avec un accent particulier sur les éléments intégratifs et conjugatifs (ICE) et ICEcIc. L'état actuel des connaissances sur l'organisation génétique, la régulation, l'intégration et le transfert de différents modèles de ICEs est exposé en détail. En outre, je m'étends sur les phénomènes d'hétérogénéité et de bistabilité phénotyplques, qu'on peut distinguer dans une population isogénique dans des conditions de culture homogènes, et qui sont susceptibles de jouer un rôle dans le transfert de l'élément ICE c/c, dans la mesure où il ne s'active et n'est transférable que dans une très petite sous-population de cellules. Dans le chapitre 2, je présente une analyse globale des régions promotrices minimales des gènes appartenant au régulon de la compétence pour le transfert de l'élément ICE c/c. Nous avons étudié les caractéristiques d'expression des promoteurs et, s'ils s'avéraient bistables, leur activation dans le temps par comparaison avec le mutant lntB13. Pour ce faire, nous avons utilisé des fusions de promoteurs avec des gènes rapporteurs et testé l'expression bistable chez P. knackmussii par microscopie à épifluorescence. Pour six promoteurs présentant une expression bistable, nous avons employé de la microscopie temporelle pour déterminer la chronologie de leur expression par rapport à Pint et PinR. Parmi eux, nous avons identifié deux gènes exprimés précocement et trois gènes exprimés tardivement dans le processus d'acquisition de la compétence de transfert. Dans le chapitre 3, j'expose une analyse d'expression génétique pour l'un des groupes de gènes dont la transcription est la plus élevée dans la région conservée de ICE c/c, les gènes orf81655-orf68241 contenus dans une région de 14 kb. Nous montrons d'abord que cet opéron fait partie du même régulon bistable que intB13 et inrR et analysons les caractéristiques génétiques qui conduisent à une transcription élevée. Nous étudions les fonctions biologiques de ce groupe de gènes par des délétlons ciblées et montrons que certaines d'entre elles empêchent le transfert de l'élément. Nous approfondissons la caractérlsatlon de I'orf8l655 en construisant une fusion transcrlptionnelle avec le gène codant pour la protéine fluorescente verte (egfp) (en utilisant le système minl-Tn5). L'expression de Vorf81655 dans des cellules individuelles est comparée au signal mesuré par hybridation in situ en fluorescence (FISH) sur le ARN messager du gène. En utilisant FISH, des délétlons du promoteur et de l'analyse directe de transcription, nous avons localisé la région promotrice du groupe de gènes. En outre, nous avons utilisé des mutations dirigées pour comprendre la bistabilité de cette région promotrice, caractérisée par une transcription très élevée et une traduction lente de l'ARN messager.  Dans le chapitre 4, nous nous efforçons de comprendre comment la bistabilité est générée au sein du régulon te de l'élément ICE c/c. Pour ce faire, nous avons tenté de reconstituer une expression bistable, dans un hôte qui ne présente pas de bistabilité naturellement, à partir d'éléments génétiques individuels. L'hôte choisi est Pseudomonas putida dans lequel nous avons introduit une copie unique de Pint, PinR ou PaipA fusionnés à la egfp, construits qui permettent d'observer l'apparition de bistabilité. Nous avons ensuite construit différents assemblages de composants génétiques de l'élément ICE c/c, en nous concentrant sur la région parA-inrR. En effet, nous avons pu démontrer qu'une expression bistable apparaît dans P. putida grâce à ces éléments en l'absence de l'élément ICE c/c complet. À noter que la plupart des construits génétiques activent PaipA ou P|,,R, mais qu'un seul recrée la bistabilité de Pint, ce qui suggère que la région parA-inrR permet à la fois d'engendrer la bistabilité et d'opérer la transition entre les promoteurs précoces et les promoteurs tardifs du régulon de la bistabilité. Dans le chapitre 5, nous concluons sur une discussion de la pertinence de nos résultats et sur de futures perspectives de recherche. -- The 103-kb self-transmissible integrative and conjugative element (ICE) of Pseudomonas knackmussii B13 (ICEc/c) confers the capacity to degrade 3- chlorobenzoate and 2-aminophenol. ICEc/c can be conjugated from strain B13 to a variety of Beta- and Gammaproteobacteria. Interestingly, ICE c/c transfer is observed in a subpopulatlon of cells (3-5%) only, the so-called 'transfer competent' cells. The formation of transfer competence (tc) is thought to be the consequence of a 'bistable' decision, which forces those cells to follow the developmental path which leads to ICEc/c transfer, whereas in others ICE c/c remains silent and does not transfer. So far, the mechanisms and molecular partners generating this bistable transfer activation in cells of P. knackmussii B13 remain mostly unidentified. This thesis aimed at understanding the extent of the tc bistability regulon and to dissect the molecular basis of bistabillty formation of ICEc/c in P. knackmussii. The first chapter is a general Introduction on horizontal gene transfer (HGT) with particular emphasis on ICEs and ICE c/c. The emphasis is made on the current knowledge about the HGT gene organization, regulation and specific integration and transfer aspects of the different ICEs models. Furthermore, I focus on the phenomena of phenotypic heterogeneity and bistability (the property of two distinguishable phenotypes existing within an isogenic population under homogeneous conditions), which may play a particular role in ICEc/c behaviour, since ICE activation and transfer only occurs in a very small subpopulation of cells. In Chapter Two, I focus on a global analysis of the different core promoters that might belong to the ICEc/c tc pathway regulon. We studied both expression patterns of ICEc/c promoters and, once being identified as "bistable", their temporal activation compared to that of intB13. In order to do this, we used promoter reporter fusions and tested blstability expression in P. knackmussii using epifluorescence microscopy. For the 6 promoters that showed bistable expression, we used time-lapse microscopy to study the timing of promoter expression in comparison to that of P,,,t or PlnR. We could establish two "early" and 3 "late" phase promoters in the process of transfer competence. In Chapter Three, I focused my attention on analysis of gene expression of one of the most highly transcribed gene clusters in the conserved core region of ICEc/c, a 14-kb gene cluster formed by the genes orf81655-orf68241. First we showed that this operon is part of the same bistability 'regulon' as intB13 and inrR, and analysed the genetic features that lead to high transcription. We studied the potential biological function of this cluster for ICE c/c by making specific gene deletions, showing that some interrupt ICEc/c transfer. We further analysed the orfdl655 promoter by constructing transcriptional egfp fusion reporter strains using the miniTn5 delivery system. Expression of the orf81655 promoter in single cells was compared to signals measured by Fluorescence In Situ Hybridization (FISH) on orfSl655 mRNA. We localized the promoter region of the gene cluster using FISH, promoter deletions, and by direct transcript analysis. We further used site-directed mutagenesis to understand the bistability character of the promoter region and the extremely high transcription but low translation from this mRNA. In Chapter Four, we set out to understand how bistability is generated in the tc pathway of ICEc/c. For this we tried rebuilding bistable expression from ICEc/c individual gene components in a host, which normally does not display bistability. As host we used P. putida without ICEc/c but with a single copy Pint-, PlnR- or PalpA- egfp fusion that enabled us to verify bistability formation. Subsequently, we built different assemblages of ICEc/c gene components, focusing on the parA-inrR region. Indeed, we found that bistable expression can be build from those components in P. putida without ICEc/c. Interestingly, most genetic constructs activated PaipA or PlnR, but only one resulted in bistable activation of PinT. This suggests that the parA-inrR region acts as a bistability "generator", but also as a bistability "relay" from early to late promoters in the tc pathway hierarchy. In the final fifth chapter, we conclude with a discussion of the relevance of the present thesis and the resulting perspectives for future studies.

Conservation banking and the economization of nature : an institutional analysis

During the last decade, conservation banking mechanisms have emerged in the environmental discourse as new market instruments to promote biodiversity conservation. Compensation was already provided for in environmental law in many countries, as the last step of the mitigation hierarchy. The institutional arrangements developed in this context have been redefined and reshaped as market-based instruments (MBIs). As such, they are discursively disentangled from the complex legal-economic nexus they are part of. Monetary transactions are given prominence and tend to be presented as stand alone agreements, whereas they take place in the context of prescriptive regulations. The pro-market narrative featuring conservation banking systems as market-like arrangements as well as their denunciation as instances of nature commodification tend to obscure their actual characteristics. The purpose of this paper is to describe the latter, adopting an explicitly analytical stance on these complex institutional arrangements and their performative dimensions. Beyond the discourse supporting them and notwithstanding the diversity of national policies and regulatory frameworks for compensation, the constitutive force of these mechanisms probably lies in their ability to redefine control, power and the distribution of costs and in their impacts in terms of land use rather than in their efficiency.

Emergent power hierarchies and group performance (Published online: 7 Oct. 2014)

In newly formed groups, informal hierarchies emerge automatically and readily. In this study, we argue that emergent group hierarchies enhance group performance (Hypothesis 1) and we assume that the more the power hierarchy within a group corresponds to the task-competence differences of the individual group members, the better the group performs (Hypothesis 2). Twelve three-person groups and 28 four-person groups were investigated while solving the Winter Survival Task. Results show that emerging power hierarchies positively impact group performance but the alignment between task-competence and power hierarchy did not affect group performance. Thus, emergent power hierarchies are beneficial for group performance and although they were on average created around individual group members' competence, this correspondence was not a prerequisite for better group performance.

Aasian toinen todellisuus - Suomen suurlähetystöjen monikulttuurisen johtamisen haasteet

Monikulttuurinen johtaminen on globalisaation ja nopean kansainvälistymisen takia erittäin ajankohtainen aihe. Suomessa sitä on kuitenkin tutkittu vasta vähän. Tämän tutkimuksen tarkoituksena on tutkia Suomen suurlähetystöjenmonikulttuurista johtamista Aasian eri kohdemaissa ja kulttuureissa sekä ottaa osaa tieteelliseen keskusteluun monikulttuurisesta johtamisesta. Tutkimuksen kohdemaiksi on valittu neljä Aasian maata, jotka ovat tällä hetkellä hyvin ajankohtaisia nopean talouskasvunsa takia. Itä-Aasiasta mukana ovat Etelä-Korea (Korean tasavalta), Japani ja Kiinan kansantasavalta sekä Kaakkois-Aasiasta tutkimuksessa mukana on Malesia. Tämä tutkimus on laadullinen tutkimus, jonka aineisto koostuu kahdesta laadulliselle tutkimukselle poikkeuksellisesta avoimesta kyselystä, jotka on lähetetty edellä mainittujen maiden suurlähettiläille eri kohdemaihin. Analyysissä menetelmänä on käytetty teemoittelua, jonka avulla on voitu jäsentää saatua aineistoa. Näin teemojen vertailu on myös ollut helpompaa. Tutkimuksen tuloksista kävi ilmi, että monikulttuurinen johtaminen on erittäin haasteellista kansallisten kulttuurien eroista johtuen. Arvot ovat hyvin keskeisessä osassa kulttuuria tutkittaessa ja niiden erot voivat vaikeuttaa kanssakäymistä eri kulttuureista tulevien ihmisten kesken, koska asioiden merkitykset jäävät usein arvoituksiksi vieraasta kulttuurista tuleville henkilöille. Kansallisen kulttuurin tekijöistä kieli, arvot ja uskonto ovat merkittäviä monikulttuurisen johtamisen kannalta. Tutkimuksesta kävi myös ilmi, että Itä- Aasian maissa konfutselaisuudella on suuri merkitys yhteiskuntafilosofiana. Se on muokannut yhteiskunnan arvoja, tapoja ja rakenteita. Vanhempien ja ylempiarvoisten ihmisten arvostus ja vahvasti hierarkkinen yhteiskuntarakenne ovat tyypillisiä konfutselaisuuden piirteitä. Kulttuurin ulottuvuuksista merkityksellisempiä tämän tutkimuksen kannalta ovat yksilöllisyys vs. kollektiivisuus, valtaetäisyys ja konfutselaisuuden dynamiikka (lyhyen vs. pitkän aikavälin suuntautuminen). Kaikki tämän tutkimuksen maat ovat kollektiivisia sekä niissä valtaetäisyys on myös korkea. Tämä tuo haasteita monikulttuuriseen johtamiseen Suomen suurlähetystöissä, koska suomalainen kulttuuri on useimpien länsimaiden tapaan yksilöllinen ja valtaetäisyys on suhteellisen matala. Konfutselaisuuden dynamiikka vaikuttaa lähinnä vain Itä-Aasian maissa tuoden mukanaan erittäin vahvan hierarkian, jota ei voi sivuuttaa. Tutkimuksen aineistoa käsitellään näytenäkökulmasta, eikä sitä ei voisuoraan verrata muihin organisaatioihin tai kulttuureihin. Toisaalta jokaisen kansallisen kulttuurin ihmiset toimivat tietyllä tavalla tietyssä kontekstissa, riippumatta siitä, missä organisaatiossa he työskentelevät. Kulttuuri ohjaa ihmisen toimintaa ja kansallinen kulttuuri on yrityskulttuuria voimakkaampi tekijä.

Strategy Formulation and Implementation Case of High Tech Instruments

The strategy process is a method for strategy formulation and implementation. The strategy process is commonly used especially within bigger companies. It is important to link the strategy formulation and implementation. The objective of this thesis has been to find out improvement areas for the case company’s strategy process. The theoretical framework based on literature emphasizes on strategy process as a method for strategy formulation and implementation. The theoretical framework, several mainly ad hoc interviews and author’s observation were used as tools to analyze the case company’s strategy process. The hierarchy in between the various corporate levels provides the foundation to formulate and implement the strategies. These strategies include the corporate and strategic business area level strategies. The recommendations to improve the case company’s strategy process were formulated at corporate and strategic business area levels. These recommendations were formulated based on research and experience gained throughout the work. The role of strategic projects to implement the strategies more efficiently and organizational control over distribution were found as potential improvement areas. The resource allocation prioritizing towards the most important strategic projects was also an important improvement area.

Priorization of Customer Needs for Paperboard Trays

The objectives of the study were to introduce current issues of chilled and frozen food packaging, priorize certain customer needs and review brand owners’ opinions and ways of actions. Packaging industry and packaged food markets were reviewed. Interviews of food industry brand owners are used as data sources. Analytic hierarchy process was used to prioritize the customer needs. Food packaging, special features of ready meals, chilled and frozen food packaging, packaging industry and packaged food markets in Europe are approached using literature and market reviews and forecasts. In empirical part the customer needs of paperboard trays are prioritized. The most important features for brand owners are related in product safety and environmental issues. Paperboard trays have benefits compared to its competing packaging solutions. Paperboard is recyclable, from renewable source and it has good printability. Emerging issues of packaging technology are biodegradable package, elderly friendly features such as easiness of opening and re-closing possibility, brand protection and tamper evident solutions.

Asiakasarvoa korostavan liikkeenjohdon konsulttiyrityksen kasvumahdollisuudet

Tämän diplomityön tavoitteena on selvittää asiakasarvoa luovat kasvumahdollisuudet eräälle suomalaiselle liikkeenjohdon konsulttiyritykselle. Yrityksen kasvun tulee tapahtua pitkällä aikavälillä kannattavasti ja tukea sen toimintaa sekä liiketoiminnallisia tavoitteita. Työn teoreettiset aihealueet käsittelevät liikkeenjohdon konsultoinnin toimialaa, arvon luomista ja menestymisen edellytyksiä, asiakaspohjaa ja yhteistyömahdollisuuksia sekä kasvun johtamista. Työn empiirisessä osassa näitä aihealueita tutkittiin yrityksestä saatavien havaintojen, asiakaskyselyn sekä osakashaastattelujen avulla. Asiakasarvoa luovien kasvuvaihtoehtojen määrittämisessä käytettiin apuna analyyttistä hierarkiaprosessia. Tutkimuksen keskeisimmät havainnot olivat, että konsultointipalveluiden asiakasarvoa eniten luovat tekijät tärkeysjärjestyksessä ovat lopputuloksen laatu, ihmisten sitouttaminen kehitykseen, toimialaosaaminen, asenne, uudet näkökulmat ja osaaminen sekä hinta. Kohdeyritykselle tutkittiin viittä kasvuvaihtoehtoa ja niiden asiakasarvon tuottamiskykyä. Suositeltavat kasvuvaihtoehdot kohdeyritykselle tärkeysjärjestyksessä ovat asiakaspohjan säilyttäminen, uusien asiakkaiden hankkiminen sekä verkostojen ja allianssien hyödyntäminen.

Täydellinen esimies - case Lomaliitto

Tämän tutkimuksen päätarkoituksena oli löytää esimiestyön kehitettävät osa-alueet Lomaliiton valituissa toimipaikoissa alaisen näkökulmasta. Osa päätarkoitusta oli myös tarjota Lomaliitolle työkalut esimiestyön kehittämistarpeiden tunnistamiseen tulevaisuudessa. Lisäksi tutkimuksen tarkoituksena oli osallistua akateemiseen keskusteluun, jossa pyritään selvittämään täydellistä johtamista. Tutkimuksen päätarkoitukseen päästiin erilaisten tavoitteiden kautta käyttäen apuna sähköistä kyselyä, jolla saatiin sekä kvantitatiivista että kvalitatiivista aineistoa. Ensimmäinen tavoite oli selvittää mitä esimiehen ominaisuuksia alaiset arvostavat. Toinen tavoite oli selvittää mikä on alaisten mielestä hyvää ja huonoa esimiesten johtamisessa. Kolmas tavoite oli selvittää eroavatko alaisten arviot esimiestensä johtamisesta osastoittain, hierarkiatasoittain, sukupuolittain ja ikäluokittain tarkasteltuna. Viimeisenä tavoitteena oli selvittää eroavatko esimiesten ja alaisten arviot esimiesten johtamisesta toisistaan. Tutkimuksessa selvisi esimiehen tärkeimmät ominaisuudet, joita alaiset arvostavat. Keskimäärin alaiset arvioivat johtamisen tyydyttäväksi Lomaliiton tutkimukseen valituissa toimipaikoissa. Toimipaikkojen välillä esimiesten alaisiltaan saamat arviot ja kehitettävät ominaisuudet vaihtelivat jonkin verran. Se millaiseksi johtaminen arvioitiin, vaihteli jonkin verran myös osastoittain. Sen sijaan esimiesten saamat arviot alaisen hierarkiatason, sukupuolen ja ikäryhmän mukaan eivät kuitenkaan eronneet kovinkaan paljoa. Merkittävä ero löytyi kuitenkin vertaamalla esimiesten arvioita näiden alaisten arvioihin heidän johtamisestaan.

The Emergence of Regional ICT Regulatory Spaces

This paper examines the role that existing Latin American policy institutions and regulatory coordination mechanisms (otherwise referred to as “regional regulatory spaces”) play in innovation and development of the ICT sector. In doing so, it recognizes that sector regulation does not currently match regional development, thereby limiting its potential progress. In order to shed light on the role that the “regional regulatory space” could potentially play, the author addresses three main questions: · Is there a hierarchy of policies by which it is presumed easy to “coordinate within well-defined technical subjects” but extremely challenging to “agree in matters of public policy?” · What would happen if policy divergence became more important than convergence? Is it reasonable to consider creating “regional regulatory spaces?” or should we focus solely on technological coordination? · Do institutions capable of serving as effective regional regulatory spaces already exist in Latin America or should we consider modifying existing institutions or creating new institutions? After analyzing these three overarching areas of concern, this paper then discusses the need to create a regional space in order to harmonize ICT regulatory frameworks and public policies. Ultimately, this work aims to advance the institutional formulation beyond pre-existing efforts.

Interdependency management in universities: a case study

There remains uncertainty in scientific discussions regarding the governance of universities in new public management regimes in terms of who actually 'rules' in the university. Apparently, a strengthened management leadership is confronted with continuing elements of academic self-regulation and professional autonomy in knowledge production and diffusion. Organisational and academic rationales coexist in today's management of universities. This article endeavours to clarify some of the ambiguities pertaining to the coexistence of two authorities by demonstrating the working of 'interdependency management' that is taking place within universities. For this purpose, the authors have scrutinised research, teaching and recruitment policies in one Swiss university that is subject to such ambiguities. The study confirms existing research in that a command-and-control system is not applied. Policymaking in universities is instead based on a mix of negotiations in faculties that are taking place in the 'shadow of hierarchy', negotiated bargaining between faculties and leaders and occasional unilateral decisions of leaders. This mitigates latent conflicts between management and the academic community: strategic orientations of the university are generally accepted by the academic community while the academic community has influence on policy formulation and maintains defining powers over policy substance.

Reciprocal preening and food sharing in colour-polymorphic nestling barn owls.

Barn owl (Tyto alba) siblings preen and offer food items to one another, behaviours that can be considered prosocial because they benefit a conspecific by relieving distress or need. In experimental broods, we analysed whether such behaviours were reciprocated, preferentially exchanged between specific phenotypes, performed to avoid harassment and food theft or signals of hierarchy status. Three of the results are consistent with the hypothesis of direct reciprocity. First, food sharing was reciprocated in three-chick broods but not in pairs of siblings, that is when nestlings could choose a partner with whom to develop a reciprocating interaction. Second, a nestling was more likely to give a prey item to its sibling if the latter individual had preened the former. Third, siblings matched their investment in preening each other. Manipulation of age hierarchy showed that food stealing was directed towards older siblings but was not performed to compensate for a low level of cooperation received. Social behaviours were related to melanin-based coloration, suggesting that animals may signal their propensity to interact socially. The most prosocial phenotype (darker reddish) was also the phenotype that stole more food, and the effect of coloration on prosocial behaviour depended upon rank and sex, suggesting that colour-related prosociality is state dependent.

Evaluating forensic biology results given source level propositions

The evaluation of forensic evidence can occur at any level within the hierarchy of propositions depending on the question being asked and the amount and type of information that is taken into account within the evaluation. Commonly DNA evidence is reported given propositions that deal with the sub-source level in the hierarchy, which deals only with the possibility that a nominated individual is a source of DNA in a trace (or contributor to the DNA in the case of a mixed DNA trace). We explore the use of information obtained from examinations, presumptive and discriminating tests for body fluids, DNA concentrations and some case circumstances within a Bayesian network in order to provide assistance to the Courts that have to consider propositions at source level. We use a scenario in which the presence of blood is of interest as an exemplar and consider how DNA profiling results and the potential for laboratory error can be taken into account. We finish with examples of how the results of these reports could be presented in court using either numerical values or verbal descriptions of the results.

Agonistic strategies and spatial distribution in captive sooty mangabeys (Cercocebus atys lunulatus)

The aim of this article is to study the relationship between the dominance hierarchy and the spatial distribution of a group of captive sooty mangabeys (Cercocebus atys). The analysis of the spatial distribution of individuals in relation to their rank in the dominance hierarchy showed a clear linear hierarchy in which the dominant individual was located in central positions with regard to the rest of the group members. The large open enclosure where the group was living allowed them to adopt a high-risk agonistic strategy in which individuals attacked other individuals whose rank was significantly different from their own. The comparison of the results with a previous study of mangabeys showed that, although the dominance ranks of both groups were similar, the fact that they lived in facilities with different layouts caused different agonistic strategies to emerge and allowed the dominant individual to assume different spatial locations.

The Impact of Supervisor's Advice, Codes of Conduct, Accountability and Moral Attentiveness of Individuals on Discriminatory Behaviour Against Immigrants.

Past studies on the personnel selection demonstrated that a supervisor's advice to discriminate can lead to compliant behaviours. This study had the aim to extend past findings by examining what can overcome the powerful influence of the hierarchy. 50 Swiss managers participated to an in-basket exercise. The main task was to evaluate Swiss candidates (in-group) and foreigners (out-groups: Spanish and Kosovo Albanians) and to select two applicants for a job interview. Main results were the effect of codes of conduct to prevent discrimination against out-group applicants in the presence of a supervisor's advice to prefer in-group members. But, when participants were accountable to an audience, this beneficial effect disappears because participants followed the supervisor's advice. The second aim was to assess if the difference in responses between participants was related to their difference in moral attentiveness. Results showed some significant relationships but not always in the direction expected.

IMP2 provides an alternative to LIN28B for LET-7 target gene protection and glioma stem cell maintenance

Glioblastoma multiforme (GBM) is the most frequent and lethal primary brain tumor in adults. Accumulating evidence suggests that tumors comprise a hierarchical organization that is, at least partially, not genetically driven. Cells that reside at the apex of this hierarchy are commonly referred to as cancer stem cells (CSCs) and are believed to largely contribute to recurrence and therapeutic failure. Although the complexity of epigenetic regulation of the genome precludes prediction as to which epigenetic changes dominate CSC specification in different cancer types, the ability of microRNAs (miRNAs) to fine-tune expression of entire gene networks places them among prime candidates for establishing CSC properties. In this study we characterized the miRNA expression profile of primary GBM grown either under conditions that enrich for GSCs or their differentiated non-tumorigenic progeny (DGCs). Although, we identified a subset of miRNAs that was strongly differentially expressed between GSCs and DGCs, we observed that in GSCs both let-7 and, paradoxically, their target genes are highly expressed, suggesting protection against let-7 action. Using PAR-CLIP we show that insulin-like growth factor-2 mRNA-binding protein 2 (IMP2) provides a mechanism for let-7 target gene protection that represents an alternative to LIN28A/B, which abrogates let-7 biogenesis in normal embryonic and certain malignant stem cells. By direct binding to miRNA recognition elements, IMP2 protects its targets from let-7 mediated decay. Importantly, depletion of IMP2 in GSCs strongly impairs their self- renewal properties and tumorigenicity in vivo, a phenotype that can be rescued by expression of LIN28B, suggesting that IMP2 mainly contributes to GSC maintenance by protecting let-7 target genes from silencing. Using mouse models, we show that depletion of IMP2 in neural stem cells (NSCs) induces let-7 target gene down-regulation, impairs their clonogenic capacity, and affects differentiation. Taken together, our observations describe a novel regulatory function of IMP2 in the let-7 axis whereby it supports GSC and NSC specification. Résumé (Français) Le glioblastome (GBM) est la tumeur primaire maligne du cerveau la plus fréquente. De nombreuses études ont démontré l'existence d'une organisation hiérarchique des cellules cancéreuses liée à des mécanismes épigénétiques. Les cellules qui se trouvent au sommet de cette hiérarchie sont appelées cellules souches cancéreuses (CSC), et contribuent à l'échec thérapeutique. Bien que la complexité des régulateurs épigénétiques permette difficilement de prédire quel mécanisme contribue le plus aux propriétés des CSC, la capacité des microRNAs (miRNAs) de réguler des réseaux entiers de gènes, les placent comme des candidats de premiers choix. Ici, nous avons caractérisé le profil d'expression des miRNAs dans des tumeurs primaires de GBM cultivées dans des conditions qui enrichissent soit pour les CSC, soit pour leur contrepartie de cellules cancéreuses différences (CCD). De manière surprenante et paradoxale la famille de miRNA let-7 et leurs gènes cibles étaient hautement exprimés dans les CSC, suggérant un mécanisme de protection contre l'action des let-7. Avec l'aide de la technologie PAR-CLIP, nous démontrons que la protéine IMP2, protège les mRNAs de l'action des let-7 et représente une alternative à Lin28A/B, qui d'ordinaire réprime fortement la maturation des let-7 dans les cellules souches embryonnaires et divers cancers. En se liant à la région ciblée par les let-7, IMP2 protège ses transcrits de l'action de cette classe de microRNA qui est tumoro-supressive. La déplétion d'IMP2 dans des CSC de GBM réduit fortement leur clonogénicité in vitro et leur tumorigénicité in vivo. Ceci peut être reversé en introduisant Lin28B dans des CSC de GBM, suggérant qu'IMP2 exerce ses fonctions pro-tumorigéniques en modulant l'axe let-7. Avec l'aide de modèles murins, nous observons que la déplétion de IMP2 dans les cellules souches neurales (CSN) induit une baisse de leur clonogénicité et des cibles des miRNAs let-7, suggérant une conservation de ce mécanisme entre les CSC de GBM et les CSN. En résumé, nos observations définissent une nouvelle fonction de IMP2 dans l'axe let-7 par lequel il contribue au maintien des propriétés des CSC et des CSN.