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Localization and translation control of slam in Drosophila cellularization
No full textIn this extra view, we comment on our recent work concerning the mRNA localization of the gene slow as molasses (slam). slam is a gene essential for the polarized invagination of the plasma membrane and separation of basal and lateral cortical domains during cellularization as well as for germ cell migration in later embryogenesis. We have demonstrated an intimate relationship between slam RNA and its encoded protein. Slam RNA co-localizes and forms a complex with its encoded protein. Slam mRNA localization not only is required for reaching full levels of functional Slam protein but also depends on Slam protein. The translation of slam mRNA is subject to tight spatio-temporal regulation leading to a rapid accumulation of Slam protein and zygotic slam RNA at the furrow canal. In this extra view, we first discuss the mechanism controlling localization and translation of slam RNA. In addition, we document in detail the maternal and zygotic expression of slam RNA and protein and provide data for a function in membrane stabilization. Furthermore, we mapped the region of Slam protein mediating cortical localization in cultured cells
Correction to: Complete genome sequence analysis of the Vibrio owensii strain SH‑14 isolated from shrimp with acute hepatopancreatic necrosis disease
No full textGenetic Diversity and Distribution of Human Norovirus in China (1999-2011)
Full text linkNoroviruses (NoVs) are a leading cause of epidemic and sporadic acute gastroenteritis worldwide. However, the genetic diversity and geographical distribution of NoV isolates from China have not been well described thus far. In this study, all NoV sequences obtained in China from 1999 to 2011 (n = 983), both partial and complete genomes, were downloaded from GenBank. Genotyping and phylogenetic and recombination analyses were performed in order to gain a better understanding of the distribution and genetic diversity of NoVs in China. The results indicated that approximately 90% of NoV sequences were obtained from the coastal regions of China, and most of the NoV sequences from distinct geographical regions appeared to be closely related. GII. 4 was the most prevalent genotype, accounting for 64.4% of all genotypes, followed by GII. 12 (13.9%) and GII. 3 (7.0%). Over the last decade, the GII. 4 variants were dominated by successive circulation of GII. 4/2002, GII. 4/2004, GII. 4/2006b, and GII. 4/2008, with GII. 4/2006b continuing to date. A relatively high frequency of NoV intergenotype recombinants was identified. The most common ORF1/ORF2 intergenotype recombinant was GII. 12/GII. 4 (n = 11), and the relative frequency was up to 30% among all the recombinant strains (n = 36). These findings may aid in the evaluation and implementation of appropriate measures for monitoring NoV infectious diseases in China
Complete genome sequence analysis of the Vibrio owensii strain SH-14 isolated from shrimp with acute hepatopancreatic necrosis disease
No full textLocalization of RhoGEF2 during Drosophila cellularization is developmentally controlled by slam
No full textEssential for proper function of small GTPases of the Rho family, which control many aspects of cytoskeletal and membrane dynamics, is their temporal and spatial control by activating GDP exchange factors (GEFs) and deactivating GTPase-activating-proteins (GAPs). The regulatory mechanisms controlling these factors are not well understood, especially during development, when the organization and behaviour of cells change in a stage dependent manner. During Drosophila cellularization Rho signalling and RhoGEF2 are involved in furrow canal formation and the organization of actin and myosin. Here we analyze, how RhoGEF2 is localized at the sites of membrane invagination. We show that the PDZ domain is necessary for localization and function of RhoGEF2 and identify Slam as a factor that is necessary for RhoGEF2 localization. We also demonstrate that Slam can recruit RhoGEF2 to ectopic sites. Furthermore we find that the PDZ domain of RhoGEF2 can form a complex with Slam in vivo and that Slam transcripts and protein colocalize at the furrow canal and in basal particles. Based on these findings, we propose that accumulation of slam mRNA and protein at the presumptive invagination site provides a spatial and temporal trigger for RhoGEF2-Rho1 signalling. (C) 2010 Elsevier Ireland Ltd. All rights reserved.Deutsche Forschungsgemeinschaf
Common specific indigenous bacteria reside in the intestinal tract of Chinese mitten crab ( Eriocheir sinensis )
No full textSlam protein dictates subcellular localization and translation of its own mRNA.
No full textMany mRNAs specifically localize within the cytoplasm and are present in RNA-protein complexes. It is generally assumed that localization and complex formation of these RNAs are controlled by trans-acting proteins encoded by genes different than the RNAs themselves. Here, we analyze slow as molasses (slam) mRNA that prominently colocalizes with its encoded protein at the basal cortical compartment during cellularization. The functional implications of this striking colocalization have been unknown. Here, we show that slam mRNA translation is spatiotemporally controlled. We found that translation was largely restricted to the onset of cellularization when Slam protein levels at the basal domain sharply increase. slam mRNA was translated locally, at least partially, as not yet translated mRNA transiently accumulated at the basal region. Slam RNA accumulated at the basal domain only if Slam protein was present. Furthermore, a slam RNA with impaired localization but full coding capacity was only weakly translated. We detected a biochemical interaction of slam mRNA and protein as demonstrated by specific co-immunoprecipitation from embryonic lysate. The intimate relationship of slam mRNA and protein may constitute a positive feedback loop that facilitates and controls timely and rapid accumulation of Slam protein at the prospective basal region
Function and dynamics of slam in furrow formation in early Drosophila embryo
No full textAbstractThe Drosophila embryo undergoes a developmental transition in the blastoderm stage switching from syncytial to cellular development. The cleavage furrow, which encloses nuclei into cells, is a prominent morphological feature of this transition. It is not clear how the pattern of the furrow array is defined and how zygotic genes trigger the formation and invagination of interphase furrows. A key to these questions is provided by the gene slam, which has been previously implicated in controlling furrow invagination. Here we investigate the null phenotype of slam, the dynamics of Slam protein, and its control by the recycling endosome. We find that slam is essential for furrow invagination during cellularisation and together with nullo, for specification of the furrow. During cellularisation, Slam marks first the furrow, which is derived from the metaphase furrow of the previous mitosis. Slightly later, Slam accumulates at new furrows between daughter cells early in interphase. Slam is stably associated with the furrow canal except for the onset of cellularisation as revealed by FRAP experiments. Restriction of Slam to the furrow canal and Slam mobility during cellularisation is controlled by the recycling endosome and centrosomes. We propose a three step model. The retracting metaphase furrow leaves an initial mark. This mark and the border between corresponding daughter nuclei are refined by vesicular transport away from pericentrosomal recycling endosome towards the margins of the somatic buds. Following the onset of zygotic gene expression, Slam and Nullo together stabilise this mark and Slam triggers invagination of the cleavage furrow
Design and evaluation of nested PCR primers for specific detection of genogroup I noroviruses in oysters
No full textEnhanced ovalbumin-induced airway inflammation in CD26<sup>−/−</sup>mice
No full textIn this study, we investigated the potential role of CD26 in ovalbumin (OVA)-induced airway inflammation using CD26 gene knockout mice. Compared with WT counterparts, CD26-/- mice showed an obviously enhanced tissue response and denser pulmonary infiltrates containing eosinophils around vessels and in the parenchyma after OVA sensitization and challenge. Serum IgG, including subclasses IgG1 and IgG2a, was greatly reduced in CD26-/- mice, but serum IgE remained unchanged. CD26-/- mice had increased mRNA expression of the Th2 cytokines IL-4, IL-5, and IL-13 in the lungs compared with WT mice, whereas the levels of the pro-Th1 cytokine IL-12p40 were similar in both strains. Consequently, enhanced protein secretion of IL-4, IL-5, and IL-13 was detected in bronchoalveolar lavage (BAL) fluid from CD26-/- mice. In agreement with overexpressed Th2 cytokines, both mRNA transcript and protein levels of chemokines eotaxin and RANTES, as well as their receptors CC chemokine receptor 3 (CCR3) and CCR5, were elevated in CD26-/- mice. These results suggest a protective role for CD26 in restricting OVA-induced airway inflammation
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