echinus, required for interommatidial cell sorting and cell death in the Drosophila pupal retina, encodes a protein with homology to ubiquitin-specific proteases

Background: Programmed cell death is used to remove excess cells between ommatidia in the Drosophila pupal retina. This death is required to establish the crystalline, hexagonal packing of ommatidia that characterizes the adult fly eye. In previously described echinus mutants, interommatidial cell sorting, which precedes cell death, occurred relatively normally. Interommatidial cell death was partially suppressed, resulting in adult eyes that contained excess pigment cells, and in which ommatidia were mildly disordered. These results have suggested that echinus functions in the pupal retina primarily to promote interommatidial cell death. Results: We generated a number of new echinus alleles, some of which are likely null mutants. Analysis of these alleles provides evidence that echinus has roles in cell sorting as well as cell death. echinus encodes a protein with homology to ubiquitin-specific proteases, which cleave ubiquitin-conjugated proteins at the ubiquitin C-terminus. The echinus locus encodes multiple splice forms, including two proteins that lack residues thought to be critical for deubiquitination activity. Surprisingly, ubiquitous expression in the eye of versions of Echinus that lack residues critical for ubiquitin specific protease activity, as well as a version predicted to be functional, rescue the echinus loss-of-function phenotype. Finally, genetic interactions were not detected between echinus loss and gain-of-function and a number of known apoptotic regulators. These include Notch, EGFR, the caspases Dronc, Drice, Dcp-1, Dream, the caspase activators, Rpr, Hid, and Grim, the caspase inhibitor DIAP1, and Lozenge or Klumpfuss. Conclusions: The echinus locus encodes multiple splice forms of a protein with homology to ubiquitin-specific proteases, but protease activity is unlikely to be required for echinus function, at least when echinus is overexpressed. Characterization of likely echinus null alleles and genetic interactions suggests that echinus acts at a novel point(s) to regulate interommatidial cell sorting and/or cell death in the fly eye

Cell death regulation in Drosophila: Conservation of mechanism and unique insights

Programmed cell death, or apoptosis, is a genetically encoded form of cell suicide that results in the orderly death and phagocytic removal of excess, damaged, or dangerous cells during normal development and in the adult. The cellular machinery required to carry out apoptosis is present in most, if not all cells, but is only activated in cells instructed to die (for review see Jacobson et al. 1997). Here, we review cell death regulation in the fly in the context of a first pass look at the complete Drosophila genome and what is known about death regulation in other organisms, particularly worms and vertebrates

Digital Media and Political Participation: The Moderating Role of Political Interest across Acts and Over Time

Political interest is a potentially important moderator of the relationship between digital media use and traditional forms of political participation. We theorize that the interaction between interest and digital media can be either positive or negative, depending on whether the action is voting, an elite-directed act, or a self-directed act. To test our expectation, we use British Election Studies data from 2001, 2005, and 2010. We find that digital media use is positively and consistently associated with political talk for those lower in political interest. For voting, we find a similar relationship that appears to be strengthening over time. For the elite-directed acts of donating money and working for a party, we find a highly variable moderating effect of political interest that can be positive, negative, or nonexistent.</jats:p

Dark Energy in Chains

Dark energy affects the CMB through its perturbations and affects both CMB and Sn-Ia through its background evolution. Using recent CMB and Sn-Ia data sets, together with the most general parameterization of the dark energy equation of state available, we find that today w < -0.8 (2 sigma). We also find that the value of the normalization of the power spectrum on cluster scales, sigma8, can be used to discriminate between dynamical models of dark energy (Quintessence models) and a cosmological constant model (Lambda CDM).Comment: 4 pages, to be published in the Proceedings of the XXXIX Rencontres de Moriond 'Exploring the Universe

Complete genome sequence of Kribbella flavida type strain (IFO 14399).

The genus Kribbella consists of 15 species, with Kribbella flavida (Park et al. 1999) as the type species. The name Kribbella was formed from the acronym of the Korea Research Institute of Bioscience and Biotechnology, KRIBB. Strains of the various Kribbella species were originally isolated from soil, potato, alum slate mine, patinas of catacombs or from horse racecourses. Here we describe the features of K. flavida together with the complete genome sequence and annotation. In addition to the 5.3 Mbp genome of Nocardioides sp. JS614, this is only the second completed genome sequence of the family Nocardioidaceae. The 7,579,488 bp long genome with its 7,086 protein-coding and 60 RNA genes and is part of the Genomic Encyclopedia of Bacteria and Archaea project