Masked mRNA is stored with aggregated nuclear speckles and its asymmetric redistribution requires a homolog of mago nashi

<p>Abstract</p> <p>Background</p> <p>Many rapidly developing systems rely on the regulated translation of stored transcripts for the formation of new proteins essential for morphogenesis. The microspores of the water fern <it>Marsilea vestita </it>dehydrate as they mature. During this process both mRNA and proteins required for subsequent development are stored within the microspores as they become fully desiccated and enter into senescence. At this point microspores become transcriptionally silent and remain so upon rehydration and for the remainder of spermatogenesis. Transcriptional silencing coupled with the translation of preformed RNA makes the microspore of <it>M. vestita </it>a useful system in which to study post-transcriptional regulation of RNA.</p> <p>Results</p> <p>We have characterized the distribution of mRNA as well as several conserved markers of subnuclear bodies within the nuclei of desiccating spores. During this period, nuclear speckles containing RNA were seen to aggregate forming a single large coalescence. We found that aggregated speckles contain several masked mRNA species known to be essential for spermatogenesis. During spermatogenesis masked mRNA and associated speckle proteins were shown to fragment and asymmetrically localize to spermatogenous but not sterile cells. This asymmetric localization was disrupted by RNAi knockdown of the <it>Marsilea </it>homolog of the Exon Junction Complex core component Mago nashi.</p> <p>Conclusions</p> <p>A subset of masked mRNA is stored in association with nuclear speckles during the dormant phase of microspore development in <it>M. vestita</it>. The asymmetric distribution of specific mRNAs to spermatogenous but not sterile cells mirrors their translational activities and appears to require the EJC or EJC components. This suggests a novel role for nuclear speckles in the post-transcriptional regulation of transcripts.</p

Nucleolus: the fascinating nuclear body

Nucleoli are the prominent contrasted structures of the cell nucleus. In the nucleolus, ribosomal RNAs are synthesized, processed and assembled with ribosomal proteins. RNA polymerase I synthesizes the ribosomal RNAs and this activity is cell cycle regulated. The nucleolus reveals the functional organization of the nucleus in which the compartmentation of the different steps of ribosome biogenesis is observed whereas the nucleolar machineries are in permanent exchange with the nucleoplasm and other nuclear bodies. After mitosis, nucleolar assembly is a time and space regulated process controlled by the cell cycle. In addition, by generating a large volume in the nucleus with apparently no RNA polymerase II activity, the nucleolus creates a domain of retention/sequestration of molecules normally active outside the nucleolus. Viruses interact with the nucleolus and recruit nucleolar proteins to facilitate virus replication. The nucleolus is also a sensor of stress due to the redistribution of the ribosomal proteins in the nucleoplasm by nucleolus disruption. The nucleolus plays several crucial functions in the nucleus: in addition to its function as ribosome factory of the cells it is a multifunctional nuclear domain, and nucleolar activity is linked with several pathologies. Perspectives on the evolution of this research area are proposed

Quality management systems as a link between management and employees

This paper analyses interactions between two parties (management and employees) with regard to the question of how to successfully manage and implement a quality management system (QMS). It also introduces practical possibilities for improving the employees\u27 understanding of why a QMS must be applied and how management should behave to make it possible. The paper also introduces a role of a third party (a quality representative) who must carefully choose his actions and must, above all else, be aware of the importance of open communication channels among the first two parties. Data were obtained from a research study using a survey among employees of a Slovenian information and communication technology company over a 2-year period. We found that communication between employees and management has significant importance on employee satisfaction. Therefore, communication is the essential element of successful and continuous improvement of the quality management system, in which management must be the first to show the awareness of the real purpose of the QMS, and must attract their employees\u27 attention as well as acknowledge their expectations. However, it should be noted that this factor can be stronger in a high technology company with a higher level of employee education. Conclusions are offered to improve the relationship among all parties through an improved status of the quality representative position over employees, his formal direct access to the management and the right to exercise and manage internal auditing of the system. Nevertheless, informally his role is far greater and consists once again of the crucial element of successfully and continuously improving of the QMS: communication

Vigilância da saúde: fundamentos, interfaces e tendências Health surveillance: foundations, interfaces and tendencies

O presente artigo resgata inicialmente as formas, conteúdo e projeção operacional da vigilância epidemiológica como instrumento indispensável para o campo do saber e práticas da saúde pública. Em seguida, verificamos que o modelo de vigilância da saúde estabelece uma ampliação desse conceito operacional de vigilância, ao integrar as práticas coletivas e individuais em diferentes dimensões das necessidades de saúde, que incluem além do controle de riscos e danos, os determinantes ecossociais. Na sequência, buscamos dimensionar os distintos níveis de atuação desta prática sanitária articulados às intervenções de promoção, proteção e recuperação, sob uma lógica regionalizada e integralizada do Sistema Único de Saúde brasileiro. Por fim, argumentamos que todo o arcabouço conceitual-operacional de vigilância da saúde se constitui como uma base política e sanitária para a consolidação do paradigma da promoção da saúde no campo da Saúde Coletiva.<br>The present article rescues initially the forms, content and operational projection of the epidemiological surveillance as indispensable tool for the knowledge field and public health practices. After that, we verify that the health surveillance model establishes an enlargement of this operational concept of surveillance by integrating the collectives and individuals practices in different health necessities dimensions, which includes beyond of the risks and damages control also the eco-socials determinants. In the sequence, we search to dimension the distinct levels of actuation of this sanitary practice articulated to the interventions of promotion, protection and recovery under a located and integrated logic of the unique system of Brazilian health. Finally, we argue that all the conceptual-operational model framework of public health surveillance itself constitutes as a politics and sanitary base for the consolidation of the health promotion paradigm in the collective health field