NORMAL GENOMIC

• Fujisawa T et al.
• Genomic structure of an economically important cyanobacterium, Arthrospira(Spirulina) platensis NIES-39.
• DNA Res. 2010; 17: 85-103
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• A filamentous non-N(2)-fixing cyanobacterium, Arthrospira (Spirulina)platensis, is an important organism for industrial applications and as afood supply. Almost the complete genome of A. platensis NIES-39 wasdetermined in this study. The genome structure of A. platensis isestimated to be a single, circular chromosome of 6.8 Mb, based on opticalmapping. Annotation of this 6.7 Mb sequence yielded 6630 protein-codinggenes as well as two sets of rRNA genes and 40 tRNA genes. Of theprotein-coding genes, 78% are similar to those of other organisms; theremaining 22% are currently unknown. A total 612 kb of the genome comprisegroup II introns, insertion sequences and some repetitive elements. GroupI introns are located in a protein-coding region. Abundantrestriction-modification systems were determined. Unique features in thegene composition were noted, particularly in a large number of genes foradenylate cyclase and haemolysin-like Ca(2+)-binding proteins and inchemotaxis proteins. Filament-specific genes were highlighted bycomparative genomic analysis.

• Werner T, Liu G, Kang D, Ekengren S, Steiner H, Hultmark D
• A family of peptidoglycan recognition proteins in the fruit fly Drosophilamelanogaster.
• Proc Natl Acad Sci U S A. 2000; 97: 13772-7
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• Peptidoglycans from bacterial cell walls trigger immune responses ininsects and mammals. A peptidoglycan recognition protein, PGRP, has beencloned from moths as well as vertebrates and has been shown to participatein peptidoglycan-mediated activation of prophenoloxidase in the silk moth.Here we report that Drosophila expresses 12 PGRP genes, distributed in 8chromosomal loci on the 3 major chromosomes. By analyzing cDNA clones andgenomic databases, we grouped them into two classes: PGRP-SA, SB1, SB2,SC1A, SC1B, SC2, and SD, with short transcripts and short 5'-untranslatedregions; and PGRP-LA, LB, LC, LD, and LE, with long transcripts and long5'-untranslated regions. The predicted structures indicate that the firstgroup encodes extracellular proteins and the second group, intracellularand membrane-spanning proteins. Most PGRP genes are expressed in allpostembryonic stages. Peptidoglycan injections strongly induce five of thegenes. Transcripts from the different PGRP genes were found in immunecompetent organs such as fat body, gut, and hemocytes. We demonstrate thatat least PGRP-SA and SC1B can bind peptidoglycan, and a function inimmunity is likely for this family.

• Haug-Collet K et al.
• Cloning and characterization of a potassium-dependent sodium/calciumexchanger in Drosophila.
• J Cell Biol. 1999; 147: 659-70
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• Sodium/calcium(-potassium) exchangers (NCX and NCKX) are critical for therapid extrusion of calcium, which follows the stimulation of a variety ofexcitable cells. To further understand the mechanisms of calciumregulation in signaling, we have cloned a Drosophilasodium/calcium-potassium exchanger, Nckx30C. The overall deduced proteintopology for NCKX30C is similar to that of mammalian NCKX, having fivemembrane-spanning domains in the NH(2) terminus separated from six at theCOOH-terminal end by a large intracellular loop. We show that NCKX30Cfunctions as a potassium-dependent sodium/calcium exchanger, and is notonly expressed in adult neurons as was expected, but is also expressedduring ventral nerve cord development in the embryo and in larval imaginaldiscs. Nckx30C is expressed in a dorsal-ventral pattern in theeye-antennal disc in a pattern that is similar to, but broader than thatof wingless, suggesting that large fluxes of calcium may be occurringduring imaginal disc development. Nckx30C may not only function in theremoval of calcium and maintenance of calcium homeostasis during signalingin the adult, but may also play a critical role in signaling duringdevelopment.

• Sedkov Y et al.
• Molecular genetic analysis of the Drosophila trithorax-related gene whichencodes a novel SET domain protein.
• Mech Dev. 1999; 82: 171-9
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• The products of the trithorax and Polycomb groups genes maintain theactivity and silence, respectively, of many developmental genes includinggenes of the homeotic complexes. This transcriptional regulation is likelyto involve modification of chromatin structure. Here, we report thecloning and characterization of a new gene, trithorax-related (trr), whichshares sequence similarities with members of both the trithorax andPolycomb groups. The trr transcript is 9.6 kb in length and is presentthroughout development. The TRR protein, as predicted from the nucleotidesequence of the open reading frame, is 2431 amino acids in length andcontains a PHD finger-like domain and a SET domain, two highly conservedprotein motifs found in several trithorax and Polycomb group proteins, andin modifiers of position effect variegation. TRR is most similar insequence to the human ALR protein, suggesting that trr is a Drosophilahomologue of the ALR. TRR is also highly homologous to DrosophilaTRITHORAX protein and to its human homologue, ALL-1/HRX. However,preliminary genetic analysis of a trr null allele suggests that TRRprotein may not be involved in regulation of homeotic genes (i.e. not amember of the trithorax or Polycomb groups) or in position effectvariegation.

• Miklos GL, Yamamoto M, Burns RG, Maleszka R
• An essential cell division gene of Drosophila, absent from Saccharomyces,encodes an unusual protein with tubulin-like and myosin-like peptidemotifs.
• Proc Natl Acad Sci U S A. 1997; 94: 5189-94
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• Null mutations at the misato locus of Drosophila melanogaster areassociated with irregular chromosomal segregation at cell division. Theconsequences for morphogenesis are that mutant larvae are almost devoid ofimaginal disk tissue, have a reduction in brain size, and die before thelate third-instar larval stage. To analyze these findings, we isolatedcDNAs in and around the misato locus, mapped the breakpoints ofchromosomal deficiencies, determined which transcript corresponded to themisato gene, rescued the cell division defects in transgenic organisms,and sequenced the genomic DNA. Database searches revealed that misatocodes for a novel protein, the N-terminal half of which contains a mixtureof peptide motifs found in alpha-, beta-, and gamma-tubulins, as well as amotif related to part of the myosin heavy chain proteins. The sequencecharacteristics of misato indicate either that it arose from an ancestraltubulin-like gene, different parts of which underwent convergent evolutionto resemble motifs in the conventional tubulins, or that it arose by thecapture of motifs from different tubulin genes. The Saccharomycescerevisiae genome lacks a true homolog of the misato gene, and thisfinding highlights the emerging problem of assigning functional attributesto orphan genes that occur only in some evolutionary lineages.