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A first exon termination checkpoint preferentially suppresses extragenic transcription. Nat Struct Mol Biol 2021; 28:337-346. [PMID: 33767452 PMCID: PMC7610630 DOI: 10.1038/s41594-021-00572-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/12/2021] [Indexed: 01/31/2023]
Abstract
Interactions between the splicing machinery and RNA polymerase II increase protein-coding gene transcription. Similarly, exons and splicing signals of enhancer-generated long noncoding RNAs (elncRNAs) augment enhancer activity. However, elncRNAs are inefficiently spliced, suggesting that, compared with protein-coding genes, they contain qualitatively different exons with a limited ability to drive splicing. We show here that the inefficiently spliced first exons of elncRNAs as well as promoter-antisense long noncoding RNAs (pa-lncRNAs) in human and mouse cells trigger a transcription termination checkpoint that requires WDR82, an RNA polymerase II-binding protein, and its RNA-binding partner of previously unknown function, ZC3H4. We propose that the first exons of elncRNAs and pa-lncRNAs are an intrinsic component of a regulatory mechanism that, on the one hand, maximizes the activity of these cis-regulatory elements by recruiting the splicing machinery and, on the other, contains elements that suppress pervasive extragenic transcription.
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2
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Hong JW, Jeong CY, Yu JH, Kim SB, Kang SK, Kim SW, Kim NS, Kim KY, Park JW. Bombyx mori kynurenine 3-monooxygenase gene editing and insect molecular breeding using the clustered regularly interspaced short palindromic repeat/CRISPR associated protein 9 system. Biotechnol Prog 2020; 36:e3054. [PMID: 32706513 DOI: 10.1002/btpr.3054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 11/07/2022]
Abstract
Genome editing by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associated protein (Cas)9, a third-generation gene scissors, and molecular breeding at the genome level are attracting considerable attention as future breeding techniques. In the present study, genetic and phenotypic analyses were conducted to examine the molecular breeding of Bombyx mori through CRISPR/Cas9-mediated editing of the kynurenine 3-monooxygenase (KMO) gene. The synthesized guide RNAs (gRNAs) were analyzed using T7 endonuclease I after introduction into the BM-N silkworm cell line. To edit the silkworm gene, K1P gRNA, and Cas9 complexes were microinjected into silkworm embryos. After microinjection, the hatching rate and the incidence of mutation were determined as 18.1% and 60%, respectively. Gene mutation was verified in the heterozygous G0 generation, but no phenotypic change was observed; however, certain embryos and moths produced through sib-mating had significant differences compared to the wild-type. In successive generations, a distinct phenotypic change was also observed by continuous mating. Thus, although there are limitations in the phenotypic expression in breeding through the induction of deletion mutations, as in the present study, the process is believed to yield successful results within a shorter period compared to traditional breeding and is safer than transgenic technology.
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Affiliation(s)
- Jeong Won Hong
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Chan Young Jeong
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Jeong Hee Yu
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Su-Bae Kim
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Sang Kuk Kang
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Seong-Wan Kim
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Nam-Suk Kim
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Kee Young Kim
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Jong Woo Park
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeollabuk-do, Republic of Korea
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3
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Shirai Y, Daimon T. Mutations in cardinal are responsible for the red-1 and peach eye color mutants of the red flour beetle Tribolium castaneum. Biochem Biophys Res Commun 2020; 529:372-378. [PMID: 32703438 DOI: 10.1016/j.bbrc.2020.05.214] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 05/29/2020] [Indexed: 11/26/2022]
Abstract
Ommochromes are the major pigments found in the eyes, eggs, wings and epidermis of insects. Here, we report the identification and characterization of the gene responsible for red-1 locus of Tribolium, whose mutants have white eyes due to lack of ommochrome pigments in the eyes. Using a candidate gene approach, we demonstrated that red-1 and peach mutants have molecular defects in the cardinal gene, which encodes a haem peroxidase that is considered to convert 3-hydroxykynurenine into ommochromes in pigment granules. Our experiments showed that the expression pattern of cardinal correlates well with the progression of eye pigmentation during pupal stages. We performed gene editing experiments using the Receptor-Mediated Ovary Transduction of Cargo (ReMOT) Control technique to disrupt the cardinal gene by adult injection, and were able to establish a novel cardinal mutant line. Our complementation test provided definitive genetic evidence that cardinal is located at the red-1 locus. The present study will lead to a greater understanding of the function and diversity of ommochrome pathway genes in insects. Our successful use of ReMOT Control in beetles will facilitate the development of more efficient and versatile systems for insect genome editing by simple adult injection.
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Affiliation(s)
- Yu Shirai
- Department of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Takaaki Daimon
- Department of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan.
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4
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Cavaliere V, Lattanzi G, Andrenacci D. Silencing of Euchromatic Transposable Elements as a Consequence of Nuclear Lamina Dysfunction. Cells 2020; 9:cells9030625. [PMID: 32151001 PMCID: PMC7140440 DOI: 10.3390/cells9030625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 02/07/2023] Open
Abstract
Transposable elements (TEs) are mobile genomic sequences that are normally repressed to avoid proliferation and genome instability. Gene silencing mechanisms repress TEs by RNA degradation or heterochromatin formation. Heterochromatin maintenance is therefore important to keep TEs silent. Loss of heterochromatic domains has been linked to lamin mutations, which have also been associated with derepression of TEs. In fact, lamins are structural components of the nuclear lamina (NL), which is considered a pivotal structure in the maintenance of heterochromatin domains at the nuclear periphery in a silent state. Here, we show that a lethal phenotype associated with Lamin loss-of-function mutations is influenced by Drosophila gypsy retrotransposons located in euchromatic regions, suggesting that NL dysfunction has also effects on active TEs located in euchromatic loci. In fact, expression analysis of different long terminal repeat (LTR) retrotransposons and of one non-LTR retrotransposon located near active genes shows that Lamin inactivation determines the silencing of euchromatic TEs. Furthermore, we show that the silencing effect on euchromatic TEs spreads to the neighboring genomic regions, with a repressive effect on nearby genes. We propose that NL dysfunction may have opposed regulatory effects on TEs that depend on their localization in active or repressed regions of the genome.
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Affiliation(s)
- Valeria Cavaliere
- Dipartimento di Farmacia e Biotecnologie, Alma Mater Studiorum Università di Bologna, 40126 Bologna, Italy;
| | - Giovanna Lattanzi
- CNR Institute of Molecular Genetics “Luigi-Luca Cavalli-Sforza”, Unit of Bologna, 40136 Bologna, Italy;
- IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy
| | - Davide Andrenacci
- CNR Institute of Molecular Genetics “Luigi-Luca Cavalli-Sforza”, Unit of Bologna, 40136 Bologna, Italy;
- IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy
- Correspondence:
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5
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Zhang H, Lin Y, Shen G, Tan X, Lei C, Long W, Liu H, Zhang Y, Xu Y, Wu J, Gu J, Xia Q, Zhao P. Pigmentary analysis of eggs of the silkworm Bombyx mori. JOURNAL OF INSECT PHYSIOLOGY 2017; 101:142-150. [PMID: 28750999 DOI: 10.1016/j.jinsphys.2017.07.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/21/2017] [Accepted: 07/23/2017] [Indexed: 06/07/2023]
Abstract
Ommochromes are major pigments involved in coloration of eggs, eyes, wings, and epidermis of insects. Bombyx mori (silkworm) eggs contain a mixture of ommochrome pigments and their precursors. Here, we analyzed the pigment composition of every egg color strain using egg color mutants (w-2, pe, and re) and wild-type strains (dazao and C108) by using full wavelength scanning and high-performance liquid chromatography. We identified ommochrome pigments and their precursors in pigment extracts from non-diapause eggs and diapause eggs, and found that the quantities of ommochrome precursor 3-hydroxy-kynurenine were much higher in the diapause eggs. Ommochrome pigments were absent in the non-diapause eggs. We analyzed the pigment composition of every egg color strain and found an accumulation of 3-hydroxy-kynurenine and absence of ommochromes in the yellow eggs (w-2 and pe), suggesting that the essential factors for ommochrome biosynthesis are high levels of 3-hydroxy-kynurenine, enzymes for ommochrome synthesis and transferase, and spermatiation. Moreover, we confirmed that both decarboxylated xanthommatin and xanthommatin are major ommochrome pigments, and the quantity of decarboxylated xanthommatin is much higher than that of xanthommatin in silkworm eggs. Since ommochrome pigments can change color under oxidative/reductive conditions and the egg color mutant re turns crimson when preserved at a low temperature for a few weeks, we used an oxidation-reduction reaction in vitro to explore mechanisms behind the pigment-based color change. Specifically, during diapause, the contents of decarboxylated xanthommatin and xanthommatin are increased, and the ommochrome pigments convert into their reduced forms.
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Affiliation(s)
- Haiyan Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Ying Lin
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing 400716, China
| | - Guanwang Shen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing 400716, China
| | - Xue Tan
- College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Chao Lei
- College of Biotechnology, Southwest University, Chongqing 400716, China
| | - Wei Long
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Hongling Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Yandi Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Yinying Xu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Jinxin Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Jianjian Gu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing 400716, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing 400716, China.
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6
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Beasley V, Dowse H. Suppression of Tryptophan 2,3-Dioxygenase Produces a Slow Heartbeat Phenotype in Drosophila melanogaster. ACTA ACUST UNITED AC 2017; 325:651-664. [PMID: 28127944 DOI: 10.1002/jez.2057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/23/2016] [Accepted: 12/01/2016] [Indexed: 12/27/2022]
Abstract
The primary pathway utilizing tryptophan leads initially to kynurenine before branching. Products include nicotinamide adenine dinucleotide and important pigments in the eye. Products in this pathway have been linked to a number of pathologies. The gene encoding the first step in this pathway, tryptophan 2,3-dioxegenase, is encoded by the gene vermilion, initially discovered in Drosophila. In the fly, v is an important eye color marker, but is found to have multiple pleiotropic effects. We have uncovered significant effects of this mutation on the fly heart. The heart beats more slowly and more rhythmically in both males and females and in strains which we have outcrossed. In addition, the fly heart normally beats irregularly with multiple brief stoppages, and the time structure of these stoppages, as investigated by looking at interbeat intervals, is changed in flies bearing this mutation. Fewer flies bearing the v1 mutation show long hiatuses in beat compared to wild type, however, in some strains of the mutant animals that do, the number of stoppages in much greater and the mean duration is longer.
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Affiliation(s)
- Vernon Beasley
- School of Biology and Ecology, University of Maine, Orono, Maine
| | - Harold Dowse
- School of Biology and Ecology, University of Maine, Orono, Maine.,Department of Mathematics and Statistics, University of Maine, Orono, Maine
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7
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Grant P, Maga T, Loshakov A, Singhal R, Wali A, Nwankwo J, Baron K, Johnson D. An Eye on Trafficking Genes: Identification of Four Eye Color Mutations in Drosophila. G3 (BETHESDA, MD.) 2016; 6:3185-3196. [PMID: 27558665 PMCID: PMC5068940 DOI: 10.1534/g3.116.032508] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/02/2016] [Indexed: 12/30/2022]
Abstract
Genes that code for proteins involved in organelle biogenesis and intracellular trafficking produce products that are critical in normal cell function . Conserved orthologs of these are present in most or all eukaryotes, including Drosophila melanogaster Some of these genes were originally identified as eye color mutants with decreases in both types of pigments found in the fly eye. These criteria were used for identification of such genes, four eye color mutations that are not annotated in the genome sequence: chocolate, maroon, mahogany, and red Malpighian tubules were molecularly mapped and their genome sequences have been evaluated. Mapping was performed using deletion analysis and complementation tests. chocolate is an allele of the VhaAC39-1 gene, which is an ortholog of the Vacuolar H+ ATPase AC39 subunit 1. maroon corresponds to the Vps16A gene and its product is part of the HOPS complex, which participates in transport and organelle fusion. red Malpighian tubule is the CG12207 gene, which encodes a protein of unknown function that includes a LysM domain. mahogany is the CG13646 gene, which is predicted to be an amino acid transporter. The strategy of identifying eye color genes based on perturbations in quantities of both types of eye color pigments has proven useful in identifying proteins involved in trafficking and biogenesis of lysosome-related organelles. Mutants of these genes can form the basis of valuable in vivo models to understand these processes.
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Affiliation(s)
- Paaqua Grant
- Department of Biological Sciences, The George Washington University, Washington, DC 20052
| | - Tara Maga
- Department of Biological Sciences, The George Washington University, Washington, DC 20052 Undergraduate Summer Research Program, Department of Biological Sciences, The George Washington University, Washington, DC 20052
| | - Anna Loshakov
- Department of Biological Sciences, The George Washington University, Washington, DC 20052
| | - Rishi Singhal
- Department of Biological Sciences, The George Washington University, Washington, DC 20052
| | - Aminah Wali
- Undergraduate Summer Research Program, Department of Biological Sciences, The George Washington University, Washington, DC 20052
| | - Jennifer Nwankwo
- Undergraduate Summer Research Program, Department of Biological Sciences, The George Washington University, Washington, DC 20052
| | - Kaitlin Baron
- Department of Biological Sciences, The George Washington University, Washington, DC 20052
| | - Diana Johnson
- Department of Biological Sciences, The George Washington University, Washington, DC 20052
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8
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Álvarez L, Lewis-Ballester A, Roitberg A, Estrin DA, Yeh SR, Marti MA, Capece L. Structural Study of a Flexible Active Site Loop in Human Indoleamine 2,3-Dioxygenase and Its Functional Implications. Biochemistry 2016; 55:2785-93. [PMID: 27112409 DOI: 10.1021/acs.biochem.6b00077] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Human indoleamine 2,3-dioxygenase catalyzes the oxidative cleavage of tryptophan to N-formyl kynurenine, the initial and rate-limiting step in the kynurenine pathway. Additionally, this enzyme has been identified as a possible target for cancer therapy. A 20-amino acid protein segment (the JK loop), which connects the J and K helices, was not resolved in the reported hIDO crystal structure. Previous studies have shown that this loop undergoes structural rearrangement upon substrate binding. In this work, we apply a combination of replica exchange molecular dynamics simulations and site-directed mutagenesis experiments to characterize the structure and dynamics of this protein region. Our simulations show that the JK loop can be divided into two regions: the first region (JK loop(C)) displays specific and well-defined conformations and is within hydrogen bonding distance of the substrate, while the second region (JK loop(N)) is highly disordered and exposed to the solvent. The peculiar flexible nature of JK loop(N) suggests that it may function as a target for post-translational modifications and/or a mediator for protein-protein interactions. In contrast, hydrogen bonding interactions are observed between the substrate and Thr379 in the highly conserved "GTGG" motif of JK loop(C), thereby anchoring JK loop(C) in a closed conformation, which secures the appropriate substrate binding mode for catalysis. Site-directed mutagenesis experiments confirm the key role of this residue, highlighting the importance of the JK loop(C) conformation in regulating the enzymatic activity. Furthermore, the existence of the partially and totally open conformations in the substrate-free form suggests a role of JK loop(C) in controlling substrate and product dynamics.
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Affiliation(s)
- Lucía Álvarez
- Dto. de Química Inorgánica, Analítica y Química Física, Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires , Buenos Aires C1428EGA, Argentina.,INQUIMAE-CONICET , Buenos Aires C1428EGA, Argentina
| | - Ariel Lewis-Ballester
- Department of Physiology and Biophysics, Albert Einstein College of Medicine , 1300 Morris Park Avenue, New York, New York 10461, United States
| | - Adrián Roitberg
- Department of Chemistry, University of Florida , 440 Leigh Hall, Gainesville, Florida 32611-7200, United States
| | - Darío A Estrin
- Dto. de Química Inorgánica, Analítica y Química Física, Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires , Buenos Aires C1428EGA, Argentina.,INQUIMAE-CONICET , Buenos Aires C1428EGA, Argentina
| | - Syun-Ru Yeh
- Department of Physiology and Biophysics, Albert Einstein College of Medicine , 1300 Morris Park Avenue, New York, New York 10461, United States
| | - Marcelo A Marti
- Dto. de Química Biologica Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires , Buenos Aires C1428EGA, Argentina.,IQUIBICEN-CONICET , Buenos Aires C1428EGA, Argentina
| | - Luciana Capece
- Dto. de Química Inorgánica, Analítica y Química Física, Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires , Buenos Aires C1428EGA, Argentina.,INQUIMAE-CONICET , Buenos Aires C1428EGA, Argentina
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9
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Positional cloning of a Bombyx pink-eyed white egg locus reveals the major role of cardinal in ommochrome synthesis. Heredity (Edinb) 2015; 116:135-45. [PMID: 26328757 DOI: 10.1038/hdy.2015.74] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 06/26/2015] [Accepted: 06/30/2015] [Indexed: 01/09/2023] Open
Abstract
Ommochromes are major insect pigments involved in coloration of compound eyes, eggs, epidermis and wings. In the silkworm Bombyx mori, adult compound eyes and eggs contain a mixture of the ommochrome pigments such as ommin and xanthommatin. Here, we identified the gene involved in ommochrome biosynthesis by positional cloning of B. mori egg and eye color mutant pink-eyed white egg (pe). The recessive homozygote of pe has bright red eyes and white or pale pink eggs instead of a normal dark coloration due to the decrease of dark ommochrome pigments. By genetic linkage analysis, we narrowed down the pe-linked region to ~258 kb, containing 17 predicted genes. RNA sequencing analyses showed that the expression of one candidate gene, the ortholog of Drosophila haem peroxidase cardinal, coincided with egg pigmentation timing, similar to other ommochrome-related genes such as Bm-scarlet and Bm-re. In two pe strains, a common missense mutation was found within a conserved motif of B. mori cardinal homolog (Bm-cardinal). RNA interference-mediated knockdown and transcription activator-like effector nuclease (TALEN)-mediated knockout of the Bm-cardinal gene produced the same phenotype as pe in terms of egg, adult eye and larval epidermis coloration. A complementation test of the pe mutant with the TALEN-mediated Bm-cardinal-deficient strain showed that the mutant phenotype could not be rescued, indicating that Bm-cardinal is responsible for pe. Moreover, knockdown of the cardinal homolog in Tribolium castaneum also induced red compound eyes. Our results indicate that cardinal plays a major role in ommochrome synthesis of holometabolous insects.
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10
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Green EW, Campesan S, Breda C, Sathyasaikumar KV, Muchowski PJ, Schwarcz R, Kyriacou CP, Giorgini F. Drosophila eye color mutants as therapeutic tools for Huntington disease. Fly (Austin) 2014; 6:117-20. [DOI: 10.4161/fly.19999] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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11
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The extended life span of Drosophila melanogaster eye-color (white and vermilion) mutants with impaired formation of kynurenine. J Neural Transm (Vienna) 2009; 117:23-6. [PMID: 19941150 DOI: 10.1007/s00702-009-0341-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 11/09/2009] [Indexed: 10/20/2022]
Abstract
Animal and human studies suggest that aging is associated with increased formation of kynurenine (KYN) from tryptophan (TRY). The rate-limiting factors of TRY-KYN metabolism are transmembrane transport of TRY, and activity of enzyme, TRY 2,3-dioxygenase (TDO2). Eye-color mutants, white (w1118) (impaired TRY transport) and vermilion (v48a and v2) (deficient TDO activity), were compared with wild-type Oregon-R (Ore-R) strain of Drosophila melanogaster. Female 1-day-old adult flies maintained on a standard medium, and acclimatized to 12-h light:12-h dark cycle were collected, and then regularly transferred to fresh medium every 3-4 days. The number of dead flies was recorded at the time of transfer. Forty flies were studied in each experimental group. The life span of w1118 (mean = 45.5 days), and v48a (mean = 47.6 days) and v2 (mean = 43.8 days), were significantly longer than of wild-type Ore-R flies (27.1 days) (p < 0.001, Logrank test). There were no differences in life span between w1118 and v48a and v2 mutants. Present results suggest that prolongation of life span may be associated with slow rate of KYN formation from TRY.
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12
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Oxidation of L-tryptophan in biology: a comparison between tryptophan 2,3-dioxygenase and indoleamine 2,3-dioxygenase. Biochem Soc Trans 2009; 37:408-12. [PMID: 19290871 DOI: 10.1042/bst0370408] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The family of haem dioxygenases catalyse the initial oxidative cleavage of L-tryptophan to N-formylkynurenine, which is the first, rate-limiting, step in the L-kynurenine pathway. In the present paper, we discuss and compare structure and function across the family of haem dioxygenases by focusing on TDO (tryptophan 2,3-dioxygenase) and IDO (indoleamine 2,3-dioxygenase), including a review of recent structural information for both enzymes. The present paper describes how the recent development of recombinant expression systems has informed our more detailed understanding of the substrate binding, catalytic activity and mechanistic properties of these haem dioxygenases.
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13
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Han Q, Beerntsen BT, Li J. The tryptophan oxidation pathway in mosquitoes with emphasis on xanthurenic acid biosynthesis. JOURNAL OF INSECT PHYSIOLOGY 2007; 53:254-63. [PMID: 17070835 PMCID: PMC2577175 DOI: 10.1016/j.jinsphys.2006.09.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 09/01/2006] [Accepted: 09/04/2006] [Indexed: 05/12/2023]
Abstract
Oxidation of tryptophan to kynurenine and 3-hydroxykynurenine (3-HK) is the major catabolic pathway in mosquitoes. However, 3-HK is oxidized easily under physiological conditions, resulting in the production of reactive radical species. To overcome this problem, mosquitoes have developed an efficient mechanism to prevent 3-HK from accumulating by converting this chemically reactive compound to the chemically stable xanthurenic acid. Interestingly, 3-HK is a precursor for the production of compound eye pigments during the pupal and early adult stages; consequently, mosquitoes need to preserve and transport 3-HK for compound eye pigmentation in pupae and adults. This review summarizes the tryptophan oxidation pathway, compares and contrasts the mosquito tryptophan oxidation pathway with other model species, and discusses possible driving forces leading to the functional adaptation and evolution of enzymes involved in the mosquito tryptophan oxidation pathway.
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Affiliation(s)
- Qian Han
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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14
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Fabrick JA, Kanost MR, Baker JE. RNAi-induced silencing of embryonic tryptophan oxygenase in the Pyralid moth, Plodia interpunctella. JOURNAL OF INSECT SCIENCE (ONLINE) 2004; 4:15. [PMID: 15861231 PMCID: PMC528875 DOI: 10.1093/jis/4.1.15] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Accepted: 02/16/2004] [Indexed: 05/09/2023]
Abstract
Gene silencing through the introduction of double-stranded RNA (RNA interference, RNAi) provides a powerful tool for the elucidation of gene function in many systems, including those where genomics and proteomics are incomplete. The use of RNAi technology for gene silencing in Lepidoptera has lacked significant attention compared to other systems. To demonstrate that RNAi can be utilized in the lepidopteran, Plodia interpunctella, we cloned a cDNA for tryptophan oxygenase, and showed that silencing of tryptophan oxygenase through RNAi during embryonic development resulted in loss of eye-color pigmentation. The complete amino acid sequence of Plodia tryptophan oxygenase can be accessed through NCBI Protein Database.
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Affiliation(s)
- Jeffrey A. Fabrick
- Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA
- USDA, ARS, Grain Marketing and Production Research Center, 1515 College Avenue, Manhattan, KS 66502, USA
- Current address: Department of Entomology, University of Arizona, Tucson, AZ 85721 USA
| | - Michael R. Kanost
- Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA
| | - James E. Baker
- USDA, ARS, Grain Marketing and Production Research Center, 1515 College Avenue, Manhattan, KS 66502, USA
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15
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Alvarez L, Comendador MA, Sierra LM. O-ethylthymidine adducts are the most relevant damages for mutation induced by N-ethyl-N-nitrosourea in female germ cells of Drosophila melanogaster. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2002; 40:143-152. [PMID: 12203408 DOI: 10.1002/em.10101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Responses to genotoxic agents vary not only among organisms, test systems, and cellular stages, but also between sexes; little, however, is known about the mutagenic consequences of chemical exposures to female germ cells. In this study, the mutagenicity of N-ethyl-N-nitrosourea (ENU) was analyzed in female germ cells of Drosophila melanogaster using the recessive-lethal test and the vermilion system, which simultaneously generates information on induced mutation frequency and mutation spectrum. ENU was mutagenic in all stages of oogenesis, although there were differences among the stages. In mature and immature oocytes, ENU-induced mutations in the vermilion locus were 43.5% A:T-->G:C transitions, 39.1% A:T-->T:A transversions, 8.7% G:C-->A:T transitions, and 8.7% A:T-->C:G transversions, indicating that the most important premutagenic lesions induced by this chemical are O(4)-ethylthymine and O(2)-ethylthymine. The low frequency of mutation involving O(6)-ethylguanine (i.e., G:C-->A:T transitions) could be a consequence of the repair of these lesions by O(6)-methylguanine DNA methyltransferase. Comparison of these results with those previously obtained in male germ cells stresses the importance of the repair activity of the analyzed cells, because the mutation spectrum in female germ cells was similar to the spectrum obtained with repair-proficient spermatogonial cells and different from repair-deficient postmeiotic cells. The results also indicate that studies with female germ cells could be an alternative to the use of premeiotic male germ cells, especially when the analysis of these cells is difficult or almost impossible and when studies of in vivo DNA repair in premeiotic germ cells are performed.
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Affiliation(s)
- L Alvarez
- Departamento de Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias, Area de Genética, Universidad de Oviedo, Spain
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16
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Lorenzen MD, Brown SJ, Denell RE, Beeman RW. Cloning and characterization of the Tribolium castaneum eye-color genes encoding tryptophan oxygenase and kynurenine 3-monooxygenase. Genetics 2002; 160:225-34. [PMID: 11805058 PMCID: PMC1461952 DOI: 10.1093/genetics/160.1.225] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The use of eye-color mutants and their corresponding genes as scorable marker systems has facilitated the development of transformation technology in Drosophila and other insects. In the red flour beetle, Tribolium castaneum, the only currently available system for germline transformation employs the exogenous marker gene, EGFP, driven by an eye-specific promoter. To exploit the advantages offered by eye-pigmentation markers, we decided to develop a transformant selection system for Tribolium on the basis of mutant rescue. The Tribolium orthologs of the Drosophila eye-color genes vermilion (tryptophan oxygenase) and cinnabar (kynurenine 3-monooxygenase) were cloned and characterized. Conceptual translations of Tc vermilion (Tcv) and Tc cinnabar (Tccn) are 71 and 51% identical to their respective Drosophila orthologs. We used RNA interference (RNAi) to show that T. castaneum larvae lacking functional Tcv or Tccn gene products also lack the pigmented eyespots observed in wild-type larvae. Five available eye-color mutations were tested for linkage to Tcv or Tccn via recombinational mapping. No linkage was found between candidate mutations and Tccn. However, tight linkage was found between Tcv and the white-eye mutation white, here renamed vermilion(white) (v(w)). Molecular analysis indicates that 80% of the Tcv coding region is deleted in v(w) beetles. These observations suggest that the Tribolium eye is pigmented only by ommochromes, not pteridines, and indicate that Tcv is potentially useful as a germline transformation marker.
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Affiliation(s)
- Marcé D Lorenzen
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
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17
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Korey CA, Wilkie G, Davis I, Van Vactor D. small bristles is required for the morphogenesis of multiple tissues during Drosophila development. Genetics 2001; 159:1659-70. [PMID: 11779805 PMCID: PMC1461901 DOI: 10.1093/genetics/159.4.1659] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We found that mutations in small bristles (sbr) affect several tissues during the development of the fruit fly. In sbr embryos, neurons have defects in pathfinding and the body wall muscles have defective morphology. As adults, sbr flies have smaller and thinner bristles with a reduced diameter, suggesting a defective cytoskeleton within. The phenotypes we observe are consistent with defects in cell morphogenesis. We identified DmNXF1, the Drosophila homolog of a mRNA export protein that has been characterized in human (NXF1/TAP) and yeast (Mex67p) as the protein encoded by the small bristles locus. Given that a global decrease in mRNA export in these mutants is likely, the phenotypes we observe suggest that certain tissues are acutely sensitive to lower levels of cytoplasmic mRNA and the resultant decrease in protein synthesis during key stages of cellular morphogenesis.
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Affiliation(s)
- C A Korey
- Department of Cell Biology, The Program in Neuroscience and The Dana Farber Cancer Institute/Harvard Cancer Center, Harvard Medical School, Boston, Massachusetts 02115, USA
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18
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Sierra LM, Tosal L, Nivard MJ, Comendador MA, Vogel EW. The importance of distinct metabolites of N-nitrosodiethylamine for its in vivo mutagenic specificity. Mutat Res 2001; 483:95-104. [PMID: 11600138 DOI: 10.1016/s0027-5107(01)00233-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Although N-nitrosodiethylamine (NDEA) is a potent carcinogen in rodents and a probable human carcinogen, little attempts were made to characterize its mutation spectrum in higher eukaryotes. We have compared forward mutation frequencies at multiple (700) loci with the mutational spectrum induced at the vermilion gene of Drosophila, after exposure of post- and pre-meiotic male germ cells to NDEA. Among 30 vermilion mutants collected from post-meiotic stages were 12 G:C-->A:T transitions (40%), 8 A:T-->T:A transversions (27%), and 4 structural rearrangements (13%). The remainder were three A:T-->G:C transitions, two G:C-->C:G transversions and one G:C-->T:A transversion. The results show that although NDEA induces predominantly transitions (40% G:C-->A:T and 10% A:T-->G:C), the frequencies of transversions (37%, of which 27% of A:T-->T:A transversions) and especially of rearrangements (13%) are remarkably high. This mutation spectrum differs significantly from that produced by the direct-ethylating agent N-ethylnitrosourea (ENU), although the relative distribution of ethylated DNA adducts is similar for both carcinogens. These differences, in particular the occurrence of rearrangements, are most likely the result of the requirement of NDEA for bioactivation. Since all four rearrangements were collected from non-metabolizing spermatozoa (or late spermatids), it is hypothesized that they derived from acetaldehyde, a stable metabolite of NDEA. Due to its cytotoxicity, attempts to isolate vermilion mutants from NDEA-exposed pre-meiotic cells were largely unsuccessful, because only two mutants (one A:T-->G:C transition and one 1bp insertion) were collected from those stages. Our results show that NDEA is capable of generating carcinogenic lesions other than base pair substitutions.
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Affiliation(s)
- L M Sierra
- Departamento Biología Funcional e Instituto Universitario de Oncología, Area de Genética, University of Oviedo, 33006, Oviedo, Spain.
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19
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Yang HP, Tanikawa AY, Kondrashov AS. Molecular nature of 11 spontaneous de novo mutations in Drosophila melanogaster. Genetics 2001; 157:1285-92. [PMID: 11238412 PMCID: PMC1461551 DOI: 10.1093/genetics/157.3.1285] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To investigate the molecular nature and rate of spontaneous mutation in Drosophila melanogaster, we screened 887,000 individuals for de novo recessive loss-of-function mutations at eight loci that affect eye color. In total, 28 mutants were found in 16 independent events (13 singletons and three clusters). The molecular nature of the 13 events was analyzed. Coding exons of the locus were affected by insertions or deletions >100 nucleotides long (6 events), short frameshift insertions or deletions (4 events), and replacement nucleotide substitutions (1 event). In the case of 2 mutant alleles, coding regions were not affected. Because approximately 70% of spontaneous de novo loss-of-function mutations in Homo sapiens are due to nucleotide substitutions within coding regions, insertions and deletions appear to play a much larger role in spontaneous mutation in D. melanogaster than in H. sapiens. If so, the per nucleotide mutation rate in D. melanogaster may be lower than in H. sapiens, even if their per locus mutation rates are similar.
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Affiliation(s)
- H P Yang
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853, USA.
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20
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Nivard MJ, Aguirrezabalaga I, Ballering LA, Pastink A, Sierra LM, Vogel EW. Evaluation of the database on mutant frequencies and DNA sequence alterations of vermilion mutations induced in germ cells of Drosophila shows the importance of a neutral mutation detection system. Mutat Res 1999; 431:39-57. [PMID: 10656485 DOI: 10.1016/s0027-5107(99)00156-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The vermilion gene in Drosophila has extensively been used for the molecular analysis of mutations induced by chemicals in germ cells in vivo. The gene is located on the X-chromosome and is a useful target for the study of mutagenesis since all types of mutations are generated. We have critically evaluated this system with respect to sensitivity for mutation induction and selectivity for different types of mutations, using a database of more than 600 vermilion mutants induced in postmeiotic male germ cells by 18 mutagens. From most of these mutants the mutation has been analysed. These data showed 336 base substitutions, 96 intra-locus DNA rearrangements and 78 multi-locus deletions (MLD). Mutants containing a MLD were either heterozygous sterile or homozygous and hemizygous lethal. The distribution of both basepair (bp) changes and intra-locus rearrangements over the coding region of the vermilion gene was uniform with no preferences concerning 5' or 3' regions, certain exons, splice sites, specific amino acid changes or nonsense mutations. Possible hotspots for base substitutions seem to be related to the type of DNA damage rather than to the vermilion system. Gene mutations other than bp changes were examined on sequence characteristics flanking the deletion breakpoints. Induction frequencies of vermilion mosaic mutants were, in general, higher than those of vermilion complete mutants, suggesting that persistent lesions are the main contributors to the molecular spectra. Comparison of induction frequencies of vermilion mutants and sex-linked recessive lethal (SLRL) mutants for the 18 mutagens showed that the sensitivity of the vermilion gene against a mutagenic insult is representative for genes located on the X-chromosome. The effect of nucleotide excision repair (NER) on the formation of SLRL mutants correlated with an increase of transversions in the vermilion spectra under NER deficient conditions. Furthermore, the clastogenic potency of the mutagens, i.e., the efficiency to induce chromosomal-losses vs. SLRL forward mutations, shows a positive correlation with the percentage of DNA deletions in the molecular spectra of vermilion mutants.
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Affiliation(s)
- M J Nivard
- Medical Genetics Centre South-West Netherlands (MGC), Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Centre, The Netherlands.
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21
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Hamblin MT, Veuille M. Population structure among African and derived populations of Drosophila simulans: evidence for ancient subdivision and recent admixture. Genetics 1999; 153:305-17. [PMID: 10471714 PMCID: PMC1460727 DOI: 10.1093/genetics/153.1.305] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Previous studies based on allozyme variation have found little evidence for genetic differentiation in Drosophila simulans. On the basis of DNA sequence variation at two nuclear loci in four African populations of D. simulans, we show that there is significant structure to D. simulans populations within Africa. Variation at one of the loci, vermilion, appears to be neutral and supports an eastern African origin for European and American populations. Samples from the West Indies, Europe, and North America had a nucleotide diversity lower than that of African populations at vermilion and show nonequilibrium haplotype distributions at both vermilion and G6pd, consistent with a hypothesis of recent bottleneck and possibly also admixture in the history of these populations. Directional selection, previously documented at G6pd, appears to have occurred within the coalescence time of the species, obscuring deep population history.
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Affiliation(s)
- M T Hamblin
- Laboratoire d'Ecologie-EPHE, Université Pierre-et-Marie Curie, 75252 Paris Cedex 05, France.
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22
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Hasegawa Y, Negishi S, Naito J, Ikeda R, Hasegawa H, Nagamura Y. Ommochrome deficiency in an albino strain of a terrestrial isopod, Armadillidium vulgare. PIGMENT CELL RESEARCH 1999; 12:275-82. [PMID: 10454296 DOI: 10.1111/j.1600-0749.1999.tb00761.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to clarify the cause of ommochrome deficiency in an albino strain of the terrestrial isopod, Armadillidium vulgare, levels of xanthommatin, 3-hydroxykynurenine, 3-hydroxyanthranilic acid and tryptophan in whole body extracts of the albino and the wild type individuals were determined together with enzyme activities of kynurenine-3-hydroxylase, kynureninase and tryptophan-2,3-dioxygenase. Xanthommatin could not be detected in the albinos. The levels of 3-hydroxykynurenine and 3-hydroxyanthranilic acid were determined by high-performance liquid chromatography (HPLC) with electrochemical detection and were markedly low in the albinos compared with the wild type individuals. In contrast to those, the tryptophan levels determined by HPLC with fluorescence detection did not differ significantly between the two phenotypes. In the albino A. vulgare, kynurenine-3-hydroxylase activity was lower and kynureninase activity was higher than in the wild type, although the differences were not statistically significant. Tryptophan-2,3-dioxygenase activity in the albinos was less than 10% that in the wild type. Thus, ommochrome deficiency in the albino A. vulgare is considered to be caused by the extremely low activity of tryptophan-2,3-dioxygenase.
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Affiliation(s)
- Y Hasegawa
- Department of Biology, Keio University, Yokohama, Japan
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23
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Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
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24
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Davis MB, Dietz J, Standiford DM, Emerson CP. Transposable element insertions respecify alternative exon splicing in three Drosophila myosin heavy chain mutants. Genetics 1998; 150:1105-14. [PMID: 9799262 PMCID: PMC1460390 DOI: 10.1093/genetics/150.3.1105] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Insertions of transposable elements into the myosin heavy chain (Mhc) locus disrupt the regulation of alternative pre-mRNA splicing for multi-alternative exons in the Mhc2, Mhc3, and Mhc4 mutants in Drosophila. Sequence and expression analyses show that each inserted element introduces a strong polyadenylation signal that defines novel terminal exons, which are then differentially recognized by the alternative splicing apparatus. Mhc2 and Mhc4 have insertion elements located within intron 7c and exon 9a, respectively, and each expresses a single truncated transcript that contains an aberrant terminal exon defined by the poly(A) signal of the inserted element and the 3' acceptor of the upstream common exon. In Mhc3, a poly(A) signal inserted into Mhc intron 7d defines terminal exons using either the upstream 3' acceptor of common exon 6 or the 7d acceptor, leading to the expression of 4.1- and 1.7-kb transcripts, respectively. Acceptor selection is regulated in Mhc3 transcripts, where the 3' acceptor of common Mhc exon 6 is preferentially selected in larvae, whereas the alternative exon 7d acceptor is favored in adults. These results reflect the adult-specific use of exon 7d and suggest that the normal exon 7 alternative splicing mechanism continues to influence the selection of exon 7d in Mhc3 transcripts. Overall, transposable element-induced disruptions in alternative processing demonstrate a role for the nonconsensus 3' acceptors in Mhc exons 7 and 9 alternative splicing regulation.
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Affiliation(s)
- M B Davis
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadephia, Pennsylvania 19104-6058, USA
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25
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Nabirochkin SD, Gabitova L, Ossokina MA, Soldatov AV, Gazaryan TG, Gazaryan KG. Oncoviral DNAs induce transposition of endogenous mobile elements in the genome of Drosophila melanogaster. Mutat Res 1998; 403:127-36. [PMID: 9726013 DOI: 10.1016/s0027-5107(98)00071-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Previously, we have shown that particles of Rous sarcoma virus or cloned fragments of RSV cDNA as well as DNA of oncogenic simian adenovirus Sa7, injected into the polar plasm of early Drosophila melanogaster embryos, were able to induce, with high frequency, unstable visible mutations in different groups of genetic loci. The genetic instability of the recovered mutations, i.e., their ability to revert to normal state or to generate new mutant alleles at the affected locus, was manifest in mutant lines through several generations. The molecular analysis undertaken in this study of the yellow-scute loci region which is highly sensitive to the microinjected Sa7 DNA, and of the white locus, that frequently mutates under the influence of RSV cDNA, clearly shows that the induced mutations and reversions are accompanied by insertion/excision of endogenous mobile elements. This conclusion is confirmed by in situ hybridization experiments which demonstrate that the adenovirus DNA is able to change, though with different efficiency, the chromosomal localization of certain Drosophila retrotransposons. These results partially elucidate the molecular mechanism of the genetic instability in D. melanogaster induced by microinjection of oncoviruses into early embryos, implying that is results from mobilization of endogenous transposons which play the role of insertional elements directly causing unstable mutations.
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Affiliation(s)
- S D Nabirochkin
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation.
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26
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White LD, Coates CJ, Atkinson PW, O'Brochta DA. An eye color gene for the detection of transgenic non-drosophilid insects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1996; 26:641-644. [PMID: 8995786 DOI: 10.1016/s0965-1748(96)00039-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A genetic marker for identifying transgenic Musca domestica by changes in eye color is described. The Drosophila melanogaster tryptophan oxygenase gene, vermilion (v), was tested for its ability to genetically complement the mutant tryptophan oxygenase gene in houseflies homozygous for green (ge). The v cDNA, placed under the control of the hsp82 promoter of D. pseudoobscura was transiently expressed in M. domestica embryos homozygous for the tryptophan oxygenase gene, ge, resulting in the rescue of adult eye color. The use of a gene from D. melanogaster to complement an eye color mutant in Musca provides the opportunity to develop a gene vector system for M. domestica and a select group of other non-drosophilid insects in which homologous mutations exist.
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Affiliation(s)
- L D White
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, College Park 20742-3351, USA
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27
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Nivard MJ, Pastink A, Vogel EW. Mutational spectra induced under distinct excision repair conditions by the 3 methylating agents N-methyl-N-nitrosourea, N-methyl-N'-nitro-N-nitrosoguanidine and N-nitrosodimethylamine in postmeiotic male germ cells of Drosophila. Mutat Res 1996; 352:97-115. [PMID: 8676923 DOI: 10.1016/0027-5107(96)00011-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This paper describes the analysis of mutations induced at the vermilion locus in postmeiotic male germ cell stages of Drosophila exposed to 3 different N-methyl-N-nitroso compounds: N-methyl-N-nitrosourea (MNU); N-methyl-N'-nitro-N-nitrosoguanidine (MNNG); and N-nitrosodimethylamine (DMN). With MNU and DMN, the impact of DNA nucleotide excision repair (NER) on the spectra of mutations was studied. Mutants were isolated from F1 (mutations fixed before the first mitotic replication after fertilization) and F2 (mutations fixed following one or more mitotic replications; mosaics in F1) generations. The vermilion system enables the analysis of both intra- and inter-locus DNA changes for which several techniques have been adapted: (1) amplification of the vermilion gene by PCR, cloning of the fragment and sequence analysis of ssDNA; (2) Southern blot hybridization; and (3) cytological analysis of polytene chromosomes. In total, 49 MNU (26 from the exr+ genotype and 23 from the exr- genotype), 47 DMN (28 from the exr+ genotype and 19 from the exr- genotype) and 16 MNNG-induced mutations were characterized. The F1 spectra of all 3 agents contained base-pair changes and deletions (intra- and multi-locus) in a ratio of roughly 1 to 1, indicating a significant contribution of nitrogen DNA adducts to the spectra. In all F2 spectra the levels of base-pair changes were significantly higher compared to those in the F1 spectra, a finding also made for methyl methanesulfonate-induced mutations in earlier studies. There is an increase of mutations of, especially, the transversion types of mutations under exr- conditions in comparison to the exr+ situation. The induced transversions, clearly present in all spectra (exr+ and exr-), are presumably caused by N-methyl DNA adducts, which upon release from the DNA backbone lead to apurinic sites in a time-related process. Regarding the occurrence of transitions, it turned out for all 3 mutagens that the AT-->GC type strongly dominated the GC-->AT transitions. This suggest that O6-methylguanine is efficiently repaired, in contrast to O4-methylthymine. Based on the data obtained in the vermilion system with ENU, we propose, in addition, that the Drosophila alkyltransferase system repairs O6-methylguanine more efficiently than O6-ethylguanine.
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Affiliation(s)
- M J Nivard
- MGC-Department of Radiation Genetics and Chemical Mutagenesis, Leiden University, Sylvius Laboratories, Netherlands
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28
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Warren WD, Palmer S, Howells AJ. Molecular characterization of the cinnabar region of Drosophila melanogaster: identification of the cinnabar transcription unit. Genetica 1996; 98:249-62. [PMID: 9204549 DOI: 10.1007/bf00057589] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Early studies of eye pigmentation in Drosophila melanogaster provided compelling evidence that the cinnabar (cn) gene encodes the enzyme kynurenine 3-monooxygenase (EC 1.14.13.9). Here we report the cloning of approximately 60 kb of DNA encompassing the cn gene by chromosome walking in the 43E6-F1 region of chromosome 2. An indication of the position of cn within the cloned region was obtained by molecular analysis of mutants: 9 spontaneous cn mutants were found to have either DNA insertions or deletions within a 5 kb region. In addition, a 7.8 kb restriction fragment encompassing the region altered in the mutants was observed to induce transient cn function when microinjected into cn- embryos. The cn transcription unit was identified by Northern blotting and sequence analysis of cDNA and genomic clones from this region. The predicted cn protein contains several sequence motifs common to aromatic monooxygenases and is consistent with the assignment of cn as encoding the structural gene for kynurenine 3-monooxygenase.
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Affiliation(s)
- W D Warren
- Division of Biochemistry and Molecular Biology, Faculty of Science, Australian National University, Canberra, Australia
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29
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ten Have JF, Green MM, Howells AJ. Molecular characterization of spontaneous mutations at the scarlet locus of Drosophila melanogaster. MOLECULAR & GENERAL GENETICS : MGG 1995; 249:673-81. [PMID: 8544833 DOI: 10.1007/bf00418037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Six spontaneous mutations of the scarlet (st) locus of Drosophila melanogaster have been studied at the molecular level. Two of the mutants (st1 and stsp) arose in laboratory populations, while the other four (stcob, stct89, stdct and stdv) were isolated from natural populations. In five of these there is a DNA insertion within the st region and in four cases the insertion has been identified as being a transposable element; these include the retrotransposons 412 and B104/roo, and also jockey a member of the LINE family. In the other case (stdct), the insertion appears to consist of partially duplicated st sequences. In two of the mutants (st1 and stdv) the same transposable element (412) has inserted in the same orientation at exactly the same site within the st gene. The transposable element insertions are found in intron and exon regions of the st gene and also in the putative upstream regulatory region; insertions located in introns or exons result in the production of truncated st transcripts. The results show that the same types of transposable elements that cause spontaneous mutation in laboratory stocks of D. melanogaster also cause mutation in the wild.
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Affiliation(s)
- J F ten Have
- Division of Biochemistry and Molecular Biology, Faculty of Science, Australian National University, Canberra, ACT, Australia
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30
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Chaboissier MC, Bornecque C, Busseau I, Bucheton A. A genetically tagged, defective I element can be complemented by actively transposing I factors in the germline of I-R dysgenic females in Drosophila melanogaster. MOLECULAR & GENERAL GENETICS : MGG 1995; 248:434-8. [PMID: 7565607 DOI: 10.1007/bf02191643] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Non-LTR retrotransposons, also known as LINEs, transpose by reverse transcription of an RNA intermediate. Their mechanism of transposition is apparently different from that of retrotransposons and similar to that of proviruses of retroviruses. The I factor is responsible for the I-R system of hybrid dysgenesis in Drosophila melanogaster. Inducer strains contain several functional I factors whereas reactive strains do not. Transposition of I factors can be experimentally induced: they are stable in inducer strains, but transpose at high frequency in the germline of females, known as SF females, produced by crossing reactive females and inducer males. We have constructed an I element, called IviP2, marked with the vermilion gene, the coding sequence of which was interrupted by an intron. Splicing of the intron can only occur in the transcript initiated from the I element promoter. Transposed copies expressing a wild-type vermilion phenotype were recovered in the germline of SF females in which I factors were actively transposing. This indicates that trans-complementation of a defective I element, deficient for the second open reading frame, by functional I factors can occur in the germline of dysgenic females.
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Affiliation(s)
- M C Chaboissier
- Centre de Génétique Moléculaire, CNRS, Gif-sur-Yvette, France
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Aguirrezabalaga I, Nivard MJ, Comendador MA, Vogel EW. The cross-linking agent hexamethylphosphoramide predominantly induces intra-locus and multi-locus deletions in postmeiotic germ cells of Drosophila. Genetics 1995; 139:649-58. [PMID: 7713422 PMCID: PMC1206371 DOI: 10.1093/genetics/139.2.649] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The nature of DNA sequence changes induced by the cross-linking agent hexamethylphosphoramide (HMPA) within and in the vicinity of the vermilion locus of Drosophila melanogaster that produce a vermilion mutant phenotype was analyzed after exposure of postmeiotic male germ cells. Mutagenized males were mated to either females wild-type (exr+) for nucleotide excision repair (NER) or to females having a deficiency (exr-) for NER. Rearrangements, mostly deletions, represented by far the most frequent type of mutational events induced by HMPA that are detected as vermilion mutations. In the exr+ group, all but one (a double substitution) of 21 mutants characterized were large sequence changes: we found 5 intra-locus deletions, 3 intra-locus deletions associated with insertions and 12 multi-locus deletions. When taken together, deletions and deletion/insertion mutations represent 96% of the HMPA-induced DNA modifications obtained under proficient repair conditions. Of the 10 mutants obtained from crosses with exr- females, 6 intra-locus and 2 multi-locus deletions were found, as opposed to just 1 point mutation and 1 double substitution. The "hypomutability effect" observed with exr- genotypes in relation to the wild type seems to be caused by a decrease in the frequency of multi-locus deletions in the former group. The results suggest that the NER system is involved in the generation of multi-locus deletions, whereas intra-locus deletions appear to be formed through a postreplication slipped-misrepair pathway. It is concluded that an eukaryotic in vivo system with no limitations for the recovery of multi-locus deletions, such as vermilion, should be used for the analysis of DNA damage induced by cross-linking agents.
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Affiliation(s)
- I Aguirrezabalaga
- Department of Radiation Genetics and Chemical Mutagenesis, State University of Leiden, Sylvius Laboratories, The Netherlands
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Palmer MJ, Mergner VA, Richman R, Manning JE, Kuroda MI, Lucchesi JC. The male-specific lethal-one (msl-1) gene of Drosophila melanogaster encodes a novel protein that associates with the X chromosome in males. Genetics 1993; 134:545-57. [PMID: 8325488 PMCID: PMC1205497 DOI: 10.1093/genetics/134.2.545] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Male-specific lethal-one (msl-1) is one of four genes that are required for dosage compensation in Drosophila males. To determine the molecular basis of msl-1 regulation of dosage compensation, we have cloned the gene and characterized its products. The predicted msl-1 protein (MSL-1) has no significant similarity to proteins in the current data bases but contains an acidic N terminus characteristic of proteins involved in transcription and chromatin modeling. We present evidence that the msl-1 protein is associated with hundreds of sites along the length of the X chromosome in male, but not in female, nuclei. Our findings support the hypothesis that msl-1 plays a direct role in increasing the level of X-linked gene transcription in male nuclei.
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Affiliation(s)
- M J Palmer
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280
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Sierra LM, Pastink A, Nivard MJ, Vogel EW. DNA base sequence changes induced by diethyl sulfate in postmeiotic male germ cells of Drosophila melanogaster. MOLECULAR & GENERAL GENETICS : MGG 1993; 237:370-4. [PMID: 8483451 DOI: 10.1007/bf00279440] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The DNA base sequence changes induced by diethyl sulfate (DES) were analyzed in postmeiotic male germ cells of Drosophila melanogaster. 31 transmissible vermilion mutants were recovered in F1 and F2 generations, with a frequency of 2.6 x 10(-4) for the F1, and of 1.8-13 x 10(-4) for the F2. The results show that DES induces both base pair substitutions (93%) and deletions (7%). In accord with its relatively high ability to alkylate oxygens in DNA, the most frequent type of sequence alteration among the basepair changes are GC-AT transitions, accounting for 73% of mutations, followed by transversions AT-TA (10%). DES also induced AT-GC transitions and AT-CG transversions. Both induced deletions were intralocus deletions, not occurring between basepair repeats. No influence of neighboring bases on the mutation position was found.
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Affiliation(s)
- L M Sierra
- Department of Radiation Genetics and Chemical Mutagenesis, Sylvius Laboratory, State University of Leiden, The Netherlands
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34
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Comer AR, Searles LL, Kalfayan LJ. Identification of a genomic DNA fragment containing the Drosophila melanogaster ovarian tumor gene (otu) and localization of regions governing its expression. Gene 1992; 118:171-9. [PMID: 1511891 DOI: 10.1016/0378-1119(92)90186-s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have identified a genomic DNA fragment which restores fertility to mutants of the ovarian tumor locus (otu) of Drosophila melanogaster. Germ-line transformants bearing this fragment express otu mRNA with the same tissue specificity as, and at levels comparable to, the wild-type otu gene. Transcription from the otu promoter, P(otu), which lacks a TATA element, appears to be initiated at multiple transcription start points (tsp) within an 80-bp region. Deletion of sequences upstream of the tsp indicates that a region between nucleotides -190 and -310 is required for proper expression from the otu gene. A DNA fragment containing 452 bp upstream and 126 bp downstream from the tsp is able to direct expression of the Escherichia coli lacZ gene in the germ cells of the ovary and testis, indicating that cis-acting regulatory elements governing these expression patterns are located in a 578-bp region surrounding the multiple tsp.
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Affiliation(s)
- A R Comer
- Curriculum in Genetics, University of North Carolina, Chapel Hill 27599-3280
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Purugganan M, Wessler S. The splicing of transposable elements and its role in intron evolution. Genetica 1992; 86:295-303. [PMID: 1334914 DOI: 10.1007/bf00133728] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recent studies have demonstrated that transposable elements in maize and Drosophila are spliced from pre-mRNA. These transposable element introns represent the first examples of recent addition of introns into nuclear genes. The eight reported examples of transposable element splicing include members of the maize Ac/Ds and Spm/dSpm and the Drosophila P and 412 element families. The details of the splicing of these transposable elements and their relevance to models of intron origin are discussed.
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Affiliation(s)
- M Purugganan
- Botany Department, University of Georgia, Athens 30602
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36
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Pret AM, Searles LL. Splicing of retrotransposon insertions from transcripts of the Drosophila melanogaster vermilion gene in a revertant. Genetics 1991; 129:1137-45. [PMID: 1664404 PMCID: PMC1204777 DOI: 10.1093/genetics/129.4.1137] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A mutation of the Drosophila melanogaster vermilion (v) gene known as v1 is caused by the insertion of a 412 retrotransposon into the 5' untranslated region of the first exon. Mutants carrying this insertion accumulate a low level of mRNA from which most of the transposon sequences have been eliminated by splicing at cryptic sites within transposon sequences. Here, we demonstrate that a revertant of the v1 allele called v+37 is caused by the insertion of a second retrotransposon, the B104/roo element, into a site near one end of the 412 element. The revertant strain accumulates a higher level of mRNA from which most of both transposons have been removed by splicing at new donor sites introduced by the B104/roo insertion and the same acceptor site within 412. Mutations at suppressor of sable [su(s)], which increase the accumulation of v1 transcripts, slightly elevate the level of v+37 RNA. In addition, we show that the first v intron downstream of the 412 insertion is not efficiently removed in the v1 mutant, and suppressor and reversion mutations increase the proportion of transcripts that are properly spliced at that downstream intron. Thus, it appears that both the suppressor and reversion mutations exert an effect at the level of pre-mRNA splicing.
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Affiliation(s)
- A M Pret
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280
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Pastink A, Heemskerk E, Nivard MJ, van Vliet CJ, Vogel EW. Mutational specificity of ethyl methanesulfonate in excision-repair-proficient and -deficient strains of Drosophila melanogaster. MOLECULAR & GENERAL GENETICS : MGG 1991; 229:213-8. [PMID: 1921971 DOI: 10.1007/bf00272158] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The vermilion gene was used as a target to determine the mutational specificity of ethyl methanesulfonate (EMS) in germ cells of Drosophila melanogaster. To study the impact of DNA repair on the type of mutations induced, both excision-repair-proficient (exr+) and excision-repair-deficient (exr-) strains were used for the isolation of mutant flies. In all, 28 mutants from the exr+ strain and 24 from the exr- strain, were characterized by sequence analysis. In two mutants obtained from the exr+ strain, small deletions were observed. All other mutations were caused by single base-pair changes. In two mutants double base-pair substitutions had occurred. Of the mutations induced in the exr+ strain, 22 (76%) were GC----AT transitions, 3 (10%) AT----TA transversions, 2 (6%) GC----TA transversions and 2 (6%) were deletions. As in other systems, the mutation spectrum of EMS in Drosophila is dominated by GC----AT transitions. Of the mutations in an exr- background, 12 (48%) were GC----TA transitions, 7 (28%) AT----TA transversions, 5 (20%) GC----TA transversions and 1 (4%) was a AT----GC transition. The significant increase in the contribution of transversion mutations obtained in the absence of an active maternal excision-repair mechanism, clearly indicates efficient repair of N-alkyl adducts (7-ethyl guanine and 3-ethyl adenine) by the excision-repair system in Drosophila germ cells.
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Affiliation(s)
- A Pastink
- MGC-Department of Radiation Genetics and Chemical Mutagenesis, State University of Leiden, The Netherlands
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Smith PA, Corces VG. Drosophila transposable elements: mechanisms of mutagenesis and interactions with the host genome. ADVANCES IN GENETICS 1991; 29:229-300. [PMID: 1662469 DOI: 10.1016/s0065-2660(08)60109-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- P A Smith
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218
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New nucleotide sequence data on the EMBL File Server. Nucleic Acids Res 1990; 18:4971-87. [PMID: 2395675 PMCID: PMC332045 DOI: 10.1093/nar/18.16.4971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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