The beta 3 tubulin gene is a direct target of bagpipe and biniou in the visceral mesoderm of Drosophila

Previous studies have identified the NK homeobox gene bagpipe and the FoxF fork head domain gene biniou as essential regulators of visceral mesoderm development in Drosophila. Here we present additional genetic and molecular information on the functions of these two genes during visceral mesoderm morphogenesis and differentiation. We show that both genes are required for the activation of beta 3Tub60D in the visceral mesoderm, which encodes beta 3 tubulin. We demonstrate that a 254 bp derivative of a previously defined visceral mesoderm-specific enhancer element, vm1, from beta 3Tub60D contains one specific in vitro binding site for Bagpipe and two such sites for Biniou. While the wild-type version of the 254 bp enhancer is able to drive significant levels of reporter gene expression within the entire trunk visceral mesoderm, mutation of either the Bagpipe or the Biniou binding sites within this element results in a severe decrease of enhancer activity. Moreover, mutation of all three binding sites for Bagpipe and Biniou, respectively, results in the complete loss of enhancer activity. Together, these observations suggest that Bagpipe and Biniou serve as direct, partially redundant, and tissue-specific activators of the terminal differentiation gene beta 3Tub60D in the visceral mesoderm.     

The <Emphasis Type="Italic">Drosophila</Emphasis>STIM1 orthologue,dSTIM, has roles in cell fate specification and tissue patterning

Background  

Mammalian STIM1 and STIM2 and the single Drosophila homologue dSTIM have been identified as key regulators of store-operated Ca²⁺ entry in cells. STIM proteins function both as molecular sensors of Ca²⁺concentration in the endoplasmic reticulum (ER) and the molecular triggers that activate SOC channels in the plasma membrane. Ca²⁺ is a crucial intracellular messenger utilised in many cellular processes, and regulators of Ca²⁺ homeostasis in the ER and cytosol are likely to play important roles in developmental processes. STIM protein expression is altered in several tumour types but the role of these proteins in developmental signalling pathways has not been thoroughly examined.     

<Emphasis Type="Italic">Vibrio</Emphasis> chromosomes share common history

Background  

While most gamma proteobacteria have a single circular chromosome, Vibrionales have two circular chromosomes. Horizontal gene transfer is common among Vibrios, and in light of this genetic mobility, it is an open question to what extent the two chromosomes themselves share a common history since their formation.     

Riboswitches as hormone receptors: hypothetical cytokinin-binding riboswitches in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Background  

Riboswitches are mRNA elements that change conformation when bound to small molecules. They are known to be key regulators of biosynthetic pathways in both prokaryotes and eukaryotes.     

Transcriptional regulation of respiration in yeast metabolizing differently repressive carbon substrates

Background  

Depending on the carbon source, Saccharomyces cerevisiae displays various degrees of respiration. These range from complete respiration as in the case of ethanol, to almost complete fermentation, and thus very low degrees of respiration on glucose. While many key regulators are known for these extreme cases, we focus here on regulators that are relevant at intermediate levels of respiration.     

<Emphasis Type="Italic">In situ</Emphasis>detection of non-polyadenylated RNA molecules using Turtle Probes and target primed rolling circle PRINS

Background  

In situ detection is traditionally performed with long labeled probes often followed by a signal amplification step to enhance the labeling. Whilst short probes have several advantages over long probes (e.g. higher resolution and specificity) they carry fewer labels per molecule and therefore require higher amplification for detection. Furthermore, short probes relying only on hybridization for specificity can result in non-specific signals appearing anywhere the probe attaches to the target specimen. One way to obtain high amplification whilst minimizing the risk of false positivity is to use small circular probes (e.g. Padlock Probes) in combination with target primed rolling circle DNA synthesis. This has previously been used for DNA detection in situ, but not until now for RNA targets.     

Characterisation of the role of Vrp1 in cell fusion during the development of visceral muscle of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

Background  

In Drosophila muscle cell fusion takes place both during the formation of the somatic mesoderm and the visceral mesoderm, giving rise to the skeletal muscles and the gut musculature respectively. The core process of myoblast fusion is believed to be similar for both organs. The actin cytoskeleton regulator Verprolin acts by binding to WASP, which in turn binds to the Arp2/3 complex and thus activates actin polymerization. While Verprolin has been shown to be important for somatic muscle cell fusion, the function of this protein in visceral muscle fusion has not been determined.     

The frontier between cell and organelle: genome analysis of <Emphasis Type="Italic">Candidatus</Emphasis> Carsonella ruddii

Background  

Bacterial symbioses are widespread among insects. The early establishment of such symbiotic associations has probably been one of the key factors for the evolutionary success of insects, since it may have allowed access to novel ecological niches and to new imbalanced food resources, such as plant sap or blood. Several genomes of bacterial endosymbionts of different insect species have been recently sequenced, and their biology has been extensively studied. Recently, the complete genome sequence of Candidatus Carsonella ruddii, considered the primary endosymbiont of the psyllid Pachpsylla venusta, has been published. This genome consists of a circular chromosome of 159,662 bp and has been proposed as the smallest bacterial endosymbiont genome known to date.     

Fnr (EtrA) acts as a fine-tuning regulator of anaerobic metabolism in <Emphasis Type="Italic">Shewanella oneidensis</Emphasis>MR-1

Background  

EtrA in Shewanella oneidensis MR-1, a model organism for study of adaptation to varied redox niches, shares 73.6% and 50.8% amino acid sequence identity with the oxygen-sensing regulators Fnr in E. coli and Anr in Pseudomonas aeruginosa, respectively; however, its regulatory role of anaerobic metabolism in Shewanella spp. is complex and not well understood.