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Zhao C, Swank DM. The Drosophila indirect flight muscle myosin heavy chain isoform is insufficient to transform the jump muscle into a highly stretch-activated muscle type. Am J Physiol Cell Physiol 2016; 312:C111-C118. [PMID: 27881413 DOI: 10.1152/ajpcell.00284.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/16/2016] [Accepted: 11/17/2016] [Indexed: 11/22/2022]
Abstract
Stretch activation (SA) is a delayed increase in force that enables high power and efficiency from a cyclically contracting muscle. SA exists in various degrees in almost all muscle types. In Drosophila, the indirect flight muscle (IFM) displays exceptionally high SA force production (FSA), whereas the jump muscle produces only minimal FSA We previously found that expressing an embryonic (EMB) myosin heavy chain (MHC) isoform in the jump muscle transforms it into a moderately SA muscle type and enables positive cyclical power generation. To investigate whether variation in MHC isoforms is sufficient to produce even higher FSA, we substituted the IFM MHC isoform (IFI) into the jump muscle. Surprisingly, we found that IFI only caused a 1.7-fold increase in FSA, less than half the increase previously observed with EMB, and only at a high Pi concentration, 16 mM. This IFI-induced FSA is much less than what occurs in IFM, relative to isometric tension, and did not enable positive cyclical power generation by the jump muscle. Both isometric tension and FSA of control fibers decreased with increasing Pi concentration. However, for IFI-expressing fibers, only isometric tension decreased. The rate of FSA generation was ~1.5-fold faster for IFI fibers than control fibers, and both rates were Pi dependent. We conclude that MHC isoforms can alter FSA and hence cyclical power generation but that isoforms can only endow a muscle type with moderate FSA Highly SA muscle types, such as IFM, likely use a different or additional mechanism.
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Affiliation(s)
- Cuiping Zhao
- Department of Biological Sciences, Department of Biomedical Engineering, and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Douglas M Swank
- Department of Biological Sciences, Department of Biomedical Engineering, and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
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2
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Gao J, Luo J, Fan R, Guan G, Ren Q, Ma M, Sugimoto C, Bai Q, Yin H. Molecular characterization of a myosin alkali light chain-like protein, a "concealed" antigen from the hard tick Haemaphysalis qinghaiensis. Vet Parasitol 2007; 147:140-9. [PMID: 17466457 DOI: 10.1016/j.vetpar.2007.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 03/08/2007] [Accepted: 03/12/2007] [Indexed: 10/23/2022]
Abstract
There should be some differences between antibodies generated by feeding ticks on animals and those derived by immunizing animals with tick extracts. Here, we found serum collected from sheep immunized with Haemaphysalis qinghaiensis salivary gland extracts could detect two more protein bands with molecular weights of 22 and 37 kDa (P22 and P37) on Western blots of extracts of tick salivary glands than serum from tick infected animals. Rabbit anti-H. qinghaiensis differential protein immune serum was then generated from P22 and P37 and was used to immunoscreen a cDNA library constructed from salivary glands, Malpighian tubules and ovaries of partially engorged H. qinghaiensis. A cDNA contains an open reading frame of 483 bp that codes for 160 amino acid residues with a coding capacity of 18 kDa was cloned and designated Hq02. Expression analysis by RT-PCR showed that this gene is expressed in salivary glands, midguts, other organs and different developmental stages of H. qinghaiensis. The predicted amino acid sequence of the Hq02 gene had high homology to some known myosin alkali light chain (MLC) proteins. A fusion protein consisting of 130 amino acids of Hq02 protein and 335 amino acids of T7 gene 10 protein was expressed in Escherichia coli and used to immunize sheep. Western blot showed that only rabbit anti-H. qinghaiensis differential protein immune serum could recognize the expressed Hq02 protein, while rabbit anti-H. qinghaiensis saliva immune could not. This proved Hq02 protein was a "concealed" antigen. Immunization with the recombinant Hq02 conferred a 21.8% reduction of engorgement weight for adult female ticks that fed on the immunized sheep. This is the first report of tick myosin alkali light chain and the function of this protein is discussed.
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Affiliation(s)
- Jinliang Gao
- Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
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3
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Abstract
This is the first of a projected series of canonic reviews covering all invertebrate muscle literature prior to 2005 and covers muscle genes and proteins except those involved in excitation-contraction coupling (e.g., the ryanodine receptor) and those forming ligand- and voltage-dependent channels. Two themes are of primary importance. The first is the evolutionary antiquity of muscle proteins. Actin, myosin, and tropomyosin (at least, the presence of other muscle proteins in these organisms has not been examined) exist in muscle-like cells in Radiata, and almost all muscle proteins are present across Bilateria, implying that the first Bilaterian had a complete, or near-complete, complement of present-day muscle proteins. The second is the extraordinary diversity of protein isoforms and genetic mechanisms for producing them. This rich diversity suggests that studying invertebrate muscle proteins and genes can be usefully applied to resolve phylogenetic relationships and to understand protein assembly coevolution. Fully achieving these goals, however, will require examination of a much broader range of species than has been heretofore performed.
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Affiliation(s)
- Scott L Hooper
- Neuroscience Program, Department of Biological Sciences, Irvine Hall, Ohio University, Athens, Ohio 45701, USA.
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4
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Davidson N. My Career in Molecular Biology. Annu Rev Biochem 2002. [DOI: 10.1146/annurev.biochem.72.121801.161905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
[Figure: see text] ▪ Abstract Norman Davidson’s training as a physical chemist led him to make key early contributions to the chemistry of DNA. He described the details of DNA denaturation and renaturation, concepts that still form the basis for understanding hybridization. He also applied the single-molecule resolution of the electron microscope to describing the chemistry of circular DNA, mapping specific genes, and characterizing heteroduplexes. The latter became a dominant tool for the study of nucleic acids and contributed to our knowledge of transcription, polyadenylation, and retroviral structure. The advent of cDNA cloning and restriction enzymes enabled Davidson to describe the diversity of Drosophila actin genes and to isolate the gene encoding cAMP phosphodiesterase. Davidson then turned his attention to neuroscience and participated in cDNA cloning, oocyte expression, and structure-function studies of nicotinic acetylcholine receptors, voltage-gated sodium channels, a GABA transporter, a G protein-gated potassium channel, and calcium channels. His interests also extended to synaptic plasticity, and he helped to define the role of neuronal nitric oxide synthase and of trkB receptors. His final experiments concerned the role of protein kinase A in long-term potentiation. (The abstract was written posthumously by a colleague.)
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Affiliation(s)
- Norman Davidson
- Division of Biology, California Institute of Technology, Pasadena, California 91125
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5
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Swank DM, Bartoo ML, Knowles AF, Iliffe C, Bernstein SI, Molloy JE, Sparrow JC. Alternative exon-encoded regions of Drosophila myosin heavy chain modulate ATPase rates and actin sliding velocity. J Biol Chem 2001; 276:15117-24. [PMID: 11134017 DOI: 10.1074/jbc.m008379200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To investigate the molecular functions of the regions encoded by alternative exons from the single Drosophila myosin heavy chain gene, we made the first kinetic measurements of two muscle myosin isoforms that differ in all alternative regions. Myosin was purified from the indirect flight muscles of wild-type and transgenic flies expressing a major embryonic isoform. The in vitro actin sliding velocity on the flight muscle isoform (6.4 microm x s(-1) at 22 degrees C) is among the fastest reported for a type II myosin and was 9-fold faster than with the embryonic isoform. With smooth muscle tropomyosin bound to actin, the actin sliding velocity on the embryonic isoform increased 6-fold, whereas that on the flight muscle myosin slightly decreased. No difference in the step sizes of Drosophila and rabbit skeletal myosins were found using optical tweezers, suggesting that the slower in vitro velocity with the embryonic isoform is due to altered kinetics. Basal ATPase rates for flight muscle myosin are higher than those of embryonic and rabbit myosin. These differences explain why the embryonic myosin cannot functionally substitute in vivo for the native flight muscle isoform, and demonstrate that one or more of the five myosin heavy chain alternative exons must influence Drosophila myosin kinetics.
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Affiliation(s)
- D M Swank
- Biology Department and Molecular Biology Institute, San Diego State University, San Diego, California 92182, USA.
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6
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Yamashita RA, Sellers JR, Anderson JB. Identification and analysis of the myosin superfamily in Drosophila: a database approach. J Muscle Res Cell Motil 2001; 21:491-505. [PMID: 11206129 DOI: 10.1023/a:1026589626422] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The recent sequencing of the genome of Drosophila melanogaster has provided a valuable resource for mining the database for genes of interest. We took advantage of this opportunity in an attempt to identify novel myosins in Drosophila and confirm the presence of the previously identified myosins from classes I, II, III, V, VI, and VII. The Drosophila database annotators predicted the structure of three additional proteins which we identified as novel unconventional myosins, two of which fell into classes XV and XVIII, respectively. Our own efforts predicted the presence of four additional partial sequences that appear to be myosin proteins which did not fall into any specific class. In the future comparative genomics will hopefully lead to the placement of these myosins into new classes.
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Affiliation(s)
- R A Yamashita
- Laboratory of Molecular Cardiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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7
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Bernstein SI, Milligan RA. Fine tuning a molecular motor: the location of alternative domains in the Drosophila myosin head. J Mol Biol 1997; 271:1-6. [PMID: 9300050 DOI: 10.1006/jmbi.1997.1160] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Myosin isoform sequence variation is likely critical for generating differences in contraction velocity and force production exhibited by the various skeletal muscles in an animal. To examine how myosin heavy chain (MHC) isoform diversity could affect physiological function, we studied the locations of structural differences in the motor domains of muscle MHCs from Drosophila melanogaster. Drosophila has only one muscle Mhc gene. Isoform variation is achieved by alternative splicing of a limited number of exons, clearly delineating the domains of MHC that are critical for muscle-specific functions. There are four alternative regions that contribute to the motor domain of Drosophila myosin. We used the X-ray structure of chicken skeletal S1 as a framework to examine the locations of these four regions. One lies near the ATP-binding pocket in a position where amino acid changes might be expected to modulate entry or exit of the nucleotide. Interestingly, the other three are clustered at the distal end of the molecule, surrounding the reactive cysteine SH1 and the pivot point about which the light chain-containing region swings. These observations underscore the importance of this region, distant from the site of ATP entry and the actin binding interface, as a part of the molecule where modulation of function can be achieved.
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Affiliation(s)
- S I Bernstein
- Biology Department, San Diego State University, CA 92182-4614, USA
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8
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Chandler D, McGuffin ME, Piskur J, Yao J, Baker BS, Mattox W. Evolutionary conservation of regulatory strategies for the sex determination factor transformer-2. Mol Cell Biol 1997; 17:2908-19. [PMID: 9111363 PMCID: PMC232143 DOI: 10.1128/mcb.17.5.2908] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Sex determination in Drosophila melanogaster is regulated by a cascade of splicing factors which direct the sex-specific expression of gene products needed for male and female differentiation. The splicing factor TRA-2 affects sex-specific splicing of multiple pre-mRNAs involved in sexual differentiation. The tra-2 gene itself expresses a complex set of mRNAs generated through alternative processing that collectively encode three distinct protein isoforms. The expression of these isoforms differs in the soma and germ line. In the male germ line the ratio of two isoforms present is governed by autoregulation of splicing. However, the functional significance of multiple TRA-2 isoforms has remained uncertain. Here we have examined whether the structure, function, and regulation of tra-2 are conserved in Drosophila virilis, a species diverged from D. melanogaster by over 60 million years. We find that the D. virilis homolog of tra-2 produces alternatively spliced RNAs encoding a set of protein isoforms analogous to those found in D. melanogaster. When introduced into the genome of D. melanogaster, this homolog can functionally replace the endogenous tra-2 gene for both normal female sexual differentiation and spermatogenesis. Examination of alternative mRNAs produced in D. virilis testes suggests that germ line-specific autoregulation of tra-2 function is accomplished by a strategy similar to that used in D. melanogaster. The similarity in structure and function of the tra-2 genes in these divergent Drosophila species supports the idea that sexual differentiation in D. melanogaster and D. virilis is accomplished under the control of similar regulatory pathways.
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Affiliation(s)
- D Chandler
- Department of Molecular Genetics, M.D. Anderson Cancer Center, University of Texas, Houston 77030, USA
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9
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Ericsson C, Pethö Z, Mehlin H. An on-line two-dimensional polyacrylamide gel electrophoresis protein database of adult Drosophila melanogaster. Electrophoresis 1997; 18:484-90. [PMID: 9150928 DOI: 10.1002/elps.1150180324] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An annotated two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) protein database of adult Drosophila melanogaster has been constructed, based on the protein patterns of heads, thoraces and abdomens of adult male and female Drosophila melanogaster. About 1200 major protein spots are catalogued. Common proteins, found in all body parts, as well as bodypart- and sex-specifically expressed proteins are reported. Of the major proteins, 91, or 7.5%, are differentially expressed in the two sexes or in different body parts, at least in part reflecting specific functional requirements. At the present time 43 proteins, or about 3.5% of the detected proteins, have been identified. These data can be accessed interactively from our World Wide Web (WWW) server through clickable inline gel images and hypertext links. Identified protein spots are cross-referenced, through hypertext links, to the SWISS-PROT annotated database of protein primary sequences and the Fly-Base database of Drosophila genomic data. Our reference gels can be used to gain immediate access to protein spot identify and to the pattern of differentially expressed proteins in Drosophila melanogaster. The work presented in this article ties together information from protein 2-D PAGE, molecular biology and genetics and offers a uniform way to access this large volume of data.
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Affiliation(s)
- C Ericsson
- Karolinska Institutet, Department of Cell and Molecular Biology, Medical Nobel Institute, Stockholm, Sweden.
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10
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McGrew MJ, Bogdanova N, Hasegawa K, Hughes SH, Kitsis RN, Rosenthal N. Distinct gene expression patterns in skeletal and cardiac muscle are dependent on common regulatory sequences in the MLC1/3 locus. Mol Cell Biol 1996; 16:4524-34. [PMID: 8754853 PMCID: PMC231451 DOI: 10.1128/mcb.16.8.4524] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The myosin light-chain 1/3 locus (MLC1/3) is regulated by two promoters and a downstream enhancer element which produce two protein isoforms in fast skeletal muscle at distinct stages of mouse embryogenesis. We have analyzed the expression of transcripts from the internal MLC3 promoter and determined that it is also expressed in the atria of the heart. Expression from the MLC3 promoter in these striated muscle lineages is differentially regulated during development. In transgenic mice, the MLC3 promoter is responsible for cardiac-specific reporter gene expression while the downstream enhancer augments expression in skeletal muscle. Examination of the methylation status of endogenous and transgenic promoter and enhancer elements indicates that the internal promoter is not regulated in a manner similar to that of the MLC1 promoter or the downstream enhancer. A GATA protein consensus sequence in the proximal MLC3 promoter but not the MLC1 promoter binds with high affinity to GATA-4, a cardiac muscle- and gut-specific transcription factor. Mutation of either the MEF2 or GATA motifs in the MLC3 promoter attenuates its activity in both heart and skeletal muscles, demonstrating that MLC3 expression in these two diverse muscle types is dependent on common regulatory elements.
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Affiliation(s)
- M J McGrew
- Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA
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11
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Kügler S, Plenz G, Müller PK. Two additional 5' exons in the human Vigilin gene distinguish it from the chicken gene and provide the structural basis for differential routes of gene expression. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 238:410-7. [PMID: 8681952 DOI: 10.1111/j.1432-1033.1996.0410z.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Vigilin, a 150-kDa protein, contains 14 tandemly arranged domains, each consisting of a KH RNA-binding motif and a spacer region. Here, we report on the physical structure of the human Vigilin gene with 29 exons, thereby outnumbering the chicken gene by two additional 5' exons. These additional exons, 1A and 1B, are alternatively though concurrently spliced to exon 1C which is homologous to the first exon in the chicken gene. None of the additional human exons code for an amino-terminal extension of Vigilin, due to in-frame stop codons. Structural features of exon 1A, however, would allow the translation of a 13-amino-acid peptide from an upstream open reading frame preceding the vigilin open reading frame. We suggest that exons 1A and 1B have been gained during evolution, allowing alternative routes of expression control of the human Vigilin gene.
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Affiliation(s)
- S Kügler
- Institut für Medizinische Molekularbiologie, Medizinische Universität zu Lübeck, Germany
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12
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Beckingham K. Calcium regulation of Drosophila development. ADVANCES IN SECOND MESSENGER AND PHOSPHOPROTEIN RESEARCH 1995; 30:359-94. [PMID: 7695998 DOI: 10.1016/s1040-7952(05)80015-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- K Beckingham
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251
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13
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Leicht BG, Muse SV, Hanczyc M, Clark AG. Constraints on intron evolution in the gene encoding the myosin alkali light chain in Drosophila. Genetics 1995; 139:299-308. [PMID: 7535717 PMCID: PMC1206326 DOI: 10.1093/genetics/139.1.299] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Interspecific comparisons of intron sequences reveal conserved blocks of invariant nucleotides and several other departures from the strictly neutral model of molecular evolution. To distinguish the past action of evolutionary forces in introns known to have regulatory information, we examined nucleotide sequence variation at 991 sites in a random sample of 16 Drosophila melanogaster alleles of the gene encoding the myosin alkali light chain (Mlc1). The Mlc1 gene of D. melanogaster encodes two MLC1 isoforms via developmentally regulated alternative pre-mRNA splicing. Analyses of these data reveal that introns 4 and 5, which flank the alternatively spliced exon 5, have reduced levels of both intraspecific polymorphism and interspecific divergence relative to intron 3. No polymorphism was observed in any of the exons examined in D. melanogaster. A genealogical analysis clearly demonstrates the occurrence of intragenic recombination in the ancestral history of Mlc1. Recombination events are estimated to be 13 times more likely than mutation events over the span of the sequenced region. Although there is little evidence for pairwise linkage disequilibrium in the Mlc1 region, higher order disequilibrium does seem to be present in the 5' half of the portion of the gene that was examined. Predictions of the folding free energy of the pre-mRNA reveal that sampled alleles have a significantly higher (less stable) free energy than do randomly permuted sequences. These results are consistent with the hypothesis that introns surrounding an alternatively spliced exon are subjected to additional constraints, perhaps due to specific aspects of secondary structure required for appropriate splicing of the pre-mRNA molecule.
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Affiliation(s)
- B G Leicht
- Department of Biology, Pennsylvania State University, University Park 16802
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14
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Stephan W, Rodriguez VS, Zhou B, Parsch J. Molecular evolution of the metallothionein gene Mtn in the melanogaster species group: results from Drosophila ananassae. Genetics 1994; 138:135-43. [PMID: 8001781 PMCID: PMC1206125 DOI: 10.1093/genetics/138.1.135] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Three distinctly different alleles of the metallothionein gene Mtn have been identified in natural Drosophila melanogaster populations: Mtn.3, Mtn1, and Dp(Mtn1), where the latter designates a tandem duplication of Mtn1. In Drosophila simulans, only Mtn.3-type alleles have been found. It has been suggested that Mtn.3 is the ancestral allele and demonstrated that a presumed two-step transition from Mtn.3 to Mtn1 to Dp(Mtn1) is accompanied by an approximate 5-fold increase in RNA levels. We analyzed the evolutionary genetics of the Mtn locus of Drosophila ananassae, a distant relative of D. melanogaster and D. simulans within the melanogaster species group. The Mtn gene of D. ananassae is most similar to Mtn.3: (i) it is identical with Mtn.3 at the amino acid level, but differs from Mtn1 in its terminal codon; (ii) its 3' UTR contains a characteristic extra DNA segment of about 50 bp which is present in Mtn.3, but lacking in Mtn1; (iii) duplications of Mtn were not found in a worldwide sample of 110 wild D. ananassae chromosomes. However, the intron of the Mtn gene in D. ananassae is only 69 bp long, whereas the length of the Mtn.3 and Mtn1 introns is 265 bp; and it lacks a polypyrimidine stretch upstream of the 3' splice site in contrast to the much greater pyrimidine-richness found in the Mtn.3 and Mtn1 introns. A short intron (67 bp) was also identified in a D. pseudoobscura Mtn allele, suggesting that the short intron is the ancestral form and that the transition from the short to the long intron occurred within the melanogaster species group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- W Stephan
- Department of Zoology, University of Maryland, College Park 20742
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15
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Clark AG, Silveria S, Meyers W, Langley CH. Nature screen: an efficient method for screening natural populations of Drosophila for targeted P-element insertions. Proc Natl Acad Sci U S A 1994; 91:719-22. [PMID: 8290588 PMCID: PMC43020 DOI: 10.1073/pnas.91.2.719] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The efficiency of molecular techniques is making it increasingly necessary to rely on reverse genetics to understand the function of genes. Tissue-specific libraries allow one to identify numerous genes that can be cloned, sequenced, and mapped and whose temporal and tissue-specific pattern of expression are well characterized but whose function remains unknown. In such cases, it is desirable to generate targeted mutations to examine the phenotype of loss-of-function lesions. Here we describe a method for identifying naturally occurring variants of Drosophila melanogaster with specific genes tagged by a nearby P element. Imprecise P-element excision can then be used to generate a series of small deletions in or near the gene. In the method described here, large numbers of wild-caught males were crossed to balancer females, and inserts were identified in pooled samples by the polymerase chain reaction with one primer from each target gene and one primer from the P-element terminal repeat. We present the calculations for the probability of successfully tagging a gene and show that it is greatly improved by simultaneously screening inserts into several genes. If a large natural population is available, a nature screen is faster and easier than inducing P-element transposition in the laboratory, but the resulting lines, being genetically heterogeneous, may require more subsequent work to isolate. Using this method to screen the genomes of approximately 10,400 males, we found P-element inserts in close proximity to 3 of 10 genes that were screened.
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Affiliation(s)
- A G Clark
- Department of Biology, Pennsylvania State University, University Park 16802
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16
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Nakayama S, Kretsinger RH. Evolution of EF-hand calcium-modulated proteins. III. Exon sequences confirm most dendrograms based on protein sequences: calmodulin dendrograms show significant lack of parallelism. J Mol Evol 1993; 36:458-76. [PMID: 8510179 DOI: 10.1007/bf02406722] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the first report in this series we presented dendrograms based on 152 individual proteins of the EF-hand family. In the second we used sequences from 228 proteins, containing 835 domains, and showed that eight of the 29 subfamilies are congruent and that the EF-hand domains of the remaining 21 subfamilies have diverse evolutionary histories. In this study we have computed dendrograms within and among the EF-hand subfamilies using the encoding DNA sequences. In most instances the dendrograms based on protein and on DNA sequences are very similar. Significant differences between protein and DNA trees for calmodulin remain unexplained. In our fourth report we evaluate the sequences and the distribution of introns within the EF-hand family and conclude that exon shuffling did not play a significant role in its evolution.
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Affiliation(s)
- S Nakayama
- Department of Biology, University of Virginia, Charlottesville 22901
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17
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Kretsinger RH, Nakayama S. Evolution of EF-hand calcium-modulated proteins. IV. Exon shuffling did not determine the domain compositions of EF-hand proteins. J Mol Evol 1993; 36:477-88. [PMID: 8510180 DOI: 10.1007/bf02406723] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the previous three reports in this series we demonstrated that the EF-hand family of proteins evolved by a complex pattern of gene duplication, transposition, and splicing. The dendrograms based on exon sequences are nearly identical to those based on protein sequences for troponin C, the essential light chain myosin, the regulatory light chain, and calpain. This validates both the computational methods and the dendrograms for these subfamilies. The proposal of congruence for calmodulin, troponin C, essential light chain, and regulatory light chain was confirmed. There are, however, significant differences in the calmodulin dendrograms computed from DNA and from protein sequences. In this study we find that introns are distributed throughout the EF-hand domain and the interdomain regions. Further, dendrograms based on intron type and distribution bear little resemblance to those based on protein or on DNA sequences. We conclude that introns are inserted, and probably deleted, with relatively high frequency. Further, in the EF-hand family exons do not correspond to structural domains and exon shuffling played little if any role in the evolution of this widely distributed homolog family. Calmodulin has had a turbulent evolution. Its dendrograms based on protein sequence, exon sequence, 3'-tail sequence, intron sequences, and intron positions all show significant differences.
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Affiliation(s)
- R H Kretsinger
- Department of Biology, University of Virginia, Charlottesville 22901
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18
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Huang J, Tang C, Kou G, Marchesi V, Benz E, Tang T. Genomic structure of the locus encoding protein 4.1. Structural basis for complex combinational patterns of tissue-specific alternative RNA splicing. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53759-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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19
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Bernstein SI, O'Donnell PT, Cripps RM. Molecular genetic analysis of muscle development, structure, and function in Drosophila. INTERNATIONAL REVIEW OF CYTOLOGY 1993; 143:63-152. [PMID: 8449665 DOI: 10.1016/s0074-7696(08)61874-4] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- S I Bernstein
- Department of Biology, San Diego State University, California 92182
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20
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Mattox W, Ryner L, Baker B. Autoregulation and multifunctionality among trans-acting factors that regulate alternative pre-mRNA processing. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41731-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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21
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Mount SM, Burks C, Hertz G, Stormo GD, White O, Fields C. Splicing signals in Drosophila: intron size, information content, and consensus sequences. Nucleic Acids Res 1992; 20:4255-62. [PMID: 1508718 PMCID: PMC334133 DOI: 10.1093/nar/20.16.4255] [Citation(s) in RCA: 309] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A database of 209 Drosophila introns was extracted from Genbank (release number 64.0) and examined by a number of methods in order to characterize features that might serve as signals for messenger RNA splicing. A tight distribution of sizes was observed: while the smallest introns in the database are 51 nucleotides, more than half are less than 80 nucleotides in length, and most of these have lengths in the range of 59-67 nucleotides. Drosophila splice sites found in large and small introns differ in only minor ways from each other and from those found in vertebrate introns. However, larger introns have greater pyrimidine-richness in the region between 11 and 21 nucleotides upstream of 3' splice sites. The Drosophila branchpoint consensus matrix resembles C T A A T (in which branch formation occurs at the underlined A), and differs from the corresponding mammalian signal in the absence of G at the position immediately preceding the branchpoint. The distribution of occurrences of this sequence suggests a minimum distance between 5' splice sites and branchpoints of about 38 nucleotides, and a minimum distance between 3' splice sites and branchpoints of 15 nucleotides. The methods we have used detect no information in exon sequences other than in the few nucleotides immediately adjacent to the splice sites. However, Drosophila resembles many other species in that there is a discontinuity in A + T content between exons and introns, which are A + T rich.
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Affiliation(s)
- S M Mount
- Department of Biological Sciences, Columbia University, New York, NY 10027
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22
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Rosenfeld MG, Emeson RB, Yeakley JM, Merillat N, Hedjran F, Lenz J, Delsert C. Calcitonin gene-related peptide: a neuropeptide generated as a consequence of tissue-specific, developmentally regulated alternative RNA processing events. Ann N Y Acad Sci 1992; 657:1-17. [PMID: 1637077 DOI: 10.1111/j.1749-6632.1992.tb22754.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- M G Rosenfeld
- Howard Hughes Medical Institute, University of California, Department of Medicine, San Diego, La Jolla 92093-0648
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23
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Paterson T, Beggs JD, Finnegan DJ, Lührmann R. Polypeptide components of Drosophila small nuclear ribonucleoprotein particles. Nucleic Acids Res 1991; 19:5877-82. [PMID: 1834995 PMCID: PMC329041 DOI: 10.1093/nar/19.21.5877] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In eukaryotes splicing of pre-mRNAs is mediated by the spliceosome, a dynamic complex of small nuclear ribonucleoprotein particles (snRNPs) that associate transiently during spliceosome assembly and the splicing reaction. We have purified snRNPs from nuclear extracts of Drosophila cells by affinity chromatography with an antibody specific for the trimethylguanosine (m3G) cap structure of snRNAs U1-U5. The polypeptide components of Drosophila snRNPs have been characterized and shown to consist of a number of proteins shared by all the snRNPs, and some proteins which appear to be specific to individual snRNP particles. On the basis of their apparent molecular weight and antigenicity many of these common and particle specific Drosophila snRNP proteins are remarkably conserved between Drosophila and human spliceosomes. By probing western blots of the Drosophila snRNP polypeptides with a number of antisera raised against human snRNP proteins, Drosophila polypeptides equivalent to many of the HeLa snRNP-common proteins have been identified, as well as candidates for a number of U1, U2 and U5-specific proteins.
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Affiliation(s)
- T Paterson
- Institute of Cell and Molecular Biology, University of Edinburgh
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24
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Hastings GA, Emerson CP. Myosin functional domains encoded by alternative exons are expressed in specific thoracic muscles of Drosophila. J Cell Biol 1991; 114:263-76. [PMID: 2071673 PMCID: PMC2289080 DOI: 10.1083/jcb.114.2.263] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Drosophila 36B muscle myosin heavy chain (MHC) gene has five sets of alternatively spliced exons that encode functionally important domains of the MHC protein and provide a combinatorial potential for expression of as many as 480 MHC isoforms. In this study, in situ hybridization analysis has been used to examine the complexity and muscle specificity of MHC isoform expression in the fibrillar indirect flight muscle (IFM), the tubular direct flight muscles (DFM) and tubular tergal depressor of the trochanter muscle (TDT), and the visceral esophageal muscle in the adult thorax. Our results show that alternative splicing of the MHC gene transcripts is precisely regulated in these thoracic muscles, which express three MHC isoforms. Individual thoracic muscles each express transcripts of only one isoform, as detectable by in situ hybridization. An apparently novel fourth MHC isoform, with sequence homology to the rod but not to the head domain of the 36B MHC, is expressed in two direct flight muscles. These findings form a basis for transgenic experiments designed to analyze the muscle-specific functions of MHC domains encoded by alternative exons.
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Affiliation(s)
- G A Hastings
- Biology Department, University of Virginia, Charlottesville 22901
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25
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Collins JH. Myosin light chains and troponin C: structural and evolutionary relationships revealed by amino acid sequence comparisons. J Muscle Res Cell Motil 1991; 12:3-25. [PMID: 2050809 DOI: 10.1007/bf01781170] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J H Collins
- Department of Biological Chemistry, School of Medicine, University of Maryland, Baltimore 21201
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26
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Pollenz RS, Chisholm RL. Dictyostelium discoideum essential myosin light chain: gene structure and characterization. CELL MOTILITY AND THE CYTOSKELETON 1991; 20:83-94. [PMID: 1751970 DOI: 10.1002/cm.970200202] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have used a Dictyostelium essential myosin light chain (EMLC) cDNA clone to isolate additional cDNA clones which supply a different 3' sequence from that previously described. The revised cDNA sequence encodes a polypeptide of 150 amino acids. Amino acid residues 147-167 of the previously reported sequence are replaced by new residues 147 to 150. The new cDNA encodes a polypeptide with 66% amino acid sequence identity with the Physarum polycephalum EMLC, and approximately 30% identity with mammalian EMLC sequences. These new cDNA clones were used to isolate two genomic DNA fragments which contain the entire EMLC gene. The Dictyostelium EMLC gene contains a single intron located immediately 3' of the translation initiation codon and encodes a product most similar to MLC3 isoform of vertebrates. Primer extension analysis places the transcription initiation site approximately 90 nucleotides upstream of the translation initiation site. A DNA fragment containing 350 bases of sequence upstream of the putative transcription initiation site is sufficient to drive expression of a reporter gene upon reintroduction into growing Dictyostelium cells. In addition, the CAT reporter mRNA produced by this construct showed a pattern of developmental regulation similar to that previously reported for the endogenous EMLC mRNA. Based on comparison with published EMLC sequences from a variety of sources, the Dictyostelium EMLC shows slightly higher similarity to vertebrate EMLCs from striated muscle sources than nonmuscle sources. While Dictyostelium and human nonmuscle sequences display only 28% identity over their entire sequence, the region from residue 88 to 108 shows much higher identity (67%). The high evolutionary conservation of this region of the EMLC suggests it may play an important role in EMLC function, and as such, represents a good target for future mutagenesis studies.
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Affiliation(s)
- R S Pollenz
- Department of Cell, Molecular and Structural Biology, Northwestern University Medical School, Chicago, IL 60611
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27
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Structure and expression of the Drosophila melanogaster gene for the U1 small nuclear ribonucleoprotein particle 70K protein. Mol Cell Biol 1990. [PMID: 1692955 DOI: 10.1128/mcb.10.6.2492] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A genomic clone encoding the Drosophila U1 small nuclear ribonucleoprotein particle 70K protein was isolated by hybridization with a human U1 small nuclear ribonucleoprotein particle 70K protein cDNA. Southern blot and in situ hybridizations showed that this U1 70K gene is unique in the Drosophila genome, residing at cytological position 27D1,2. Polyadenylated transcripts of 1.9 and 3.1 kilobases were observed. While the 1.9-kilobase mRNA is always more abundant, the ratio of these two transcripts is developmentally regulated. Analysis of cDNA and genomic sequences indicated that these two RNAs encode an identical protein with a predicted molecular weight of 52,879. Comparison of the U1 70K proteins predicted from Drosophila, human, and Xenopus cDNAs revealed 68% amino acid identity in the most amino-terminal 214 amino acids, which include a sequence motif common to many proteins which bind RNA. The carboxy-terminal half is less well conserved but is highly charged and contains distinctive arginine-rich regions in all three species. These arginine-rich regions contain stretches of arginine-serine dipeptides like those found in transformer, transformer-2, and suppressor-of-white-apricot proteins, all of which have been identified as regulators of mRNA splicing in Drosophila melanogaster.
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28
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Mancebo R, Lo PC, Mount SM. Structure and expression of the Drosophila melanogaster gene for the U1 small nuclear ribonucleoprotein particle 70K protein. Mol Cell Biol 1990; 10:2492-502. [PMID: 1692955 PMCID: PMC360606 DOI: 10.1128/mcb.10.6.2492-2502.1990] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A genomic clone encoding the Drosophila U1 small nuclear ribonucleoprotein particle 70K protein was isolated by hybridization with a human U1 small nuclear ribonucleoprotein particle 70K protein cDNA. Southern blot and in situ hybridizations showed that this U1 70K gene is unique in the Drosophila genome, residing at cytological position 27D1,2. Polyadenylated transcripts of 1.9 and 3.1 kilobases were observed. While the 1.9-kilobase mRNA is always more abundant, the ratio of these two transcripts is developmentally regulated. Analysis of cDNA and genomic sequences indicated that these two RNAs encode an identical protein with a predicted molecular weight of 52,879. Comparison of the U1 70K proteins predicted from Drosophila, human, and Xenopus cDNAs revealed 68% amino acid identity in the most amino-terminal 214 amino acids, which include a sequence motif common to many proteins which bind RNA. The carboxy-terminal half is less well conserved but is highly charged and contains distinctive arginine-rich regions in all three species. These arginine-rich regions contain stretches of arginine-serine dipeptides like those found in transformer, transformer-2, and suppressor-of-white-apricot proteins, all of which have been identified as regulators of mRNA splicing in Drosophila melanogaster.
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Affiliation(s)
- R Mancebo
- Department of Biological Sciences, Columbia University, New York, New York 10027
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29
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Moncrief ND, Kretsinger RH, Goodman M. Evolution of EF-hand calcium-modulated proteins. I. Relationships based on amino acid sequences. J Mol Evol 1990; 30:522-62. [PMID: 2115931 DOI: 10.1007/bf02101108] [Citation(s) in RCA: 302] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The relationships among 153 EF-hand (calcium-modulated) proteins of known amino acid sequence were determined using the method of maximum parsimony. These proteins can be ordered into 12 distinct subfamilies--calmodulin, troponin C, essential light chain of myosin, regulatory light chain, sarcoplasmic calcium binding protein, calpain, aequorin, Stronglyocentrotus purpuratus ectodermal protein, calbindin 28 kd, parvalbumin, alpha-actinin, and S100/intestinal calcium-binding protein. Eight individual proteins--calcineurin B from Bos, troponin C from Astacus, calcium vector protein from Branchiostoma, caltractin from Chlamydomonas, cell-division-cycle 31 gene product from Saccharomyces, 10-kd calcium-binding protein from Tetrahymena, LPS1 eight-domain protein from Lytechinus, and calcium-binding protein from Streptomyces--are tentatively identified as unique; that is, each may be the sole representative of another subfamily. We present dendrograms showing the relationships among the subfamilies and uniques as well as dendrograms showing relationships within each subfamily. The EF-hand proteins have been characterized from a broad range of organismal sources, and they have an enormous range of function. This is reflected in the complexity of the dendrograms. At this time we urge caution in assigning a simple scheme of gene duplications to account for the evolution of the 600 EF-hand domains of known sequence.
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Affiliation(s)
- N D Moncrief
- Department of Biology, University of Virginia, Charlottesville 22901
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30
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Functional domains of the Drosophila melanogaster muscle myosin heavy-chain gene are encoded by alternatively spliced exons. Mol Cell Biol 1989. [PMID: 2506434 DOI: 10.1128/mcb.9.7.2957] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The single-copy Drosophila muscle myosin heavy-chain (MHC) gene, located at 36B(2L), has a complex exon structure that produces a diversity of larval and adult muscle MHC isoforms through regulated alternative RNA splicing. Genomic and cDNA sequence analyses revealed that this 21-kilobase MHC gene encodes these MHC isoforms in 19 exons. However, five sets of these exons, encoding portions of the S1 head and the hinge domains of the MHC protein, are tandemly repeated as two, three, four, or five divergent copies, which are individually spliced into RNA transcripts. RNA hybridization studies with exon-specific probes showed that at least 10 of the 480 possible MHC isoforms that could arise by alternative RNA splicing of these exons are expressed as MHC transcripts and that the expression of specific members of alternative exon sets is regulated, both in stage and in muscle-type specificity. This regulated expression of specific exons is of particular interest because the alternatively spliced exon sets encode discrete domains of the MHC protein that likely contribute to the specialized contractile activities of different Drosophila muscle types. The alternative exon structure of the Drosophila MHC gene and the single-copy nature of this gene in the Drosophila genome make possible transgenic experiments to test the physiological functions of specific MHC protein domains and genetic and molecular experiments to investigate the mechanisms that regulate alternative exon splicing of MHC and other muscle gene transcripts.
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31
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Periasamy M, Wadgaonkar R, Kumar C, Martin BJ, Siddiqui MA. Characterization of a rat myosin alkali light chain gene expressed in ventricular and slow twitch skeletal muscles. Nucleic Acids Res 1989; 17:7723-34. [PMID: 2798124 PMCID: PMC334880 DOI: 10.1093/nar/17.19.7723] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mammalian cardiac muscle contains two myosin alkali light chains: 1) the atrial light chain (MLC1A), and 2) the ventricular light chain (MLC1V) predominantly expressed either in the atrium or in the ventricle. In this report we describe the isolation and characterization of the complete gene for rat MLC1V. The rat MLC1V gene is approximately 6.5 kb long and the mRNA coding sequences are organized in 7 different exons. Comparison of this gene sequence with other known MLC1 gene sequences revealed that the exon-intron organization is highly conserved within the MLC1 gene family. The derived protein sequence of rat MLC1V showed a higher sequence homology with human ventricular (96%) MLC1V than with rat fast skeletal MLC1f (74%), suggesting functional similarities between different MLC1V proteins. S1 nuclease mapping and primer extension analysis demonstrated that this gene is expressed only in ventricular and slow twitch skeletal muscle tissues and is transcribed from the same promoter and transcription initiation site.
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Affiliation(s)
- M Periasamy
- Department of Physiology and Biophysics, University of Vermont College of Medicine, Burlington 05405
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32
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Freyer GA, O'Brien JP, Hurwitz J. Alterations in the Polypyrimidine Sequence Affect the in vitro Splicing Reactions Catalyzed by HeLa cell-Free Preparations. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)63744-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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33
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George EL, Ober MB, Emerson CP. Functional domains of the Drosophila melanogaster muscle myosin heavy-chain gene are encoded by alternatively spliced exons. Mol Cell Biol 1989; 9:2957-74. [PMID: 2506434 PMCID: PMC362764 DOI: 10.1128/mcb.9.7.2957-2974.1989] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The single-copy Drosophila muscle myosin heavy-chain (MHC) gene, located at 36B(2L), has a complex exon structure that produces a diversity of larval and adult muscle MHC isoforms through regulated alternative RNA splicing. Genomic and cDNA sequence analyses revealed that this 21-kilobase MHC gene encodes these MHC isoforms in 19 exons. However, five sets of these exons, encoding portions of the S1 head and the hinge domains of the MHC protein, are tandemly repeated as two, three, four, or five divergent copies, which are individually spliced into RNA transcripts. RNA hybridization studies with exon-specific probes showed that at least 10 of the 480 possible MHC isoforms that could arise by alternative RNA splicing of these exons are expressed as MHC transcripts and that the expression of specific members of alternative exon sets is regulated, both in stage and in muscle-type specificity. This regulated expression of specific exons is of particular interest because the alternatively spliced exon sets encode discrete domains of the MHC protein that likely contribute to the specialized contractile activities of different Drosophila muscle types. The alternative exon structure of the Drosophila MHC gene and the single-copy nature of this gene in the Drosophila genome make possible transgenic experiments to test the physiological functions of specific MHC protein domains and genetic and molecular experiments to investigate the mechanisms that regulate alternative exon splicing of MHC and other muscle gene transcripts.
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Affiliation(s)
- E L George
- Biology Department, University of Virginia, Charlottesville 22901
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34
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Ayme-Southgate A, Lasko P, French C, Pardue ML. Characterization of the gene for mp20: a Drosophila muscle protein that is not found in asynchronous oscillatory flight muscle. J Cell Biol 1989; 108:521-31. [PMID: 2537318 PMCID: PMC2115408 DOI: 10.1083/jcb.108.2.521] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A Drosophila melanogaster gene encoding a muscle specific protein was isolated by differential screening with RNA from primary cultures of myotubes. The gene encodes a 20-kD protein, muscle protein 20 (mp20), that is not detected in the asynchronous oscillatory flight muscles, but is found in most, if not all, other muscles (the synchronous muscles). The sequence of the protein, deduced from the DNA, contains two regions of 12 amino acids with significant similarity to high-affinity calcium-binding sites of other proteins. This protein is easily extracted from the contractile apparatus and thus does not seem to be a tightly bound structural component. The gene (located in polytene region 49F 9-13) is unique in the D. melanogaster genome and yields two transcripts, 1.0 and 0.9 kb long. The levels of the two transcripts are regulated differently during development, yet the coding regions of the two transcripts are identical.
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Affiliation(s)
- A Ayme-Southgate
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139
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35
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Fodor WL, Darras B, Seharaseyon J, Falkenthal S, Francke U, Vanin EF. Human Ventricular/Slow Twitch Myosin Alkali Light Chain Gene Characterization, Sequence, and Chromosomal Location. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94153-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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36
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Hirsh J. Molecular genetics of dopa decarboxylase and biogenic amines in Drosophila. DEVELOPMENTAL GENETICS 1989; 10:232-8. [PMID: 2500287 DOI: 10.1002/dvg.1020100312] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The gene Ddc encodes two isoforms of the enzyme dopa decarboxylase in Drosophila. These gene products catalyze the final steps in the synthesis of the biogenic amines serotonin and dopamine. This article summarizes recent progress in understanding the tissue- and cell-specific regulation of Ddc, which occurs at both the transcription and alternate splicing levels. In addition, results that are pertinent to understanding the roles of biogenic amines in the neurophysiology of Drosophila are discussed.
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Affiliation(s)
- J Hirsh
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
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37
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Nojima H, Sokabe H. Structural organization of calmodulin genes in the rat genome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1989; 255:223-32. [PMID: 2618860 DOI: 10.1007/978-1-4684-5679-0_24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In summary, we present a list of phage clones we have obtained from rat genomic libraries (from lamba SC1 to lambda SC31, lambda WC1 and lambda WC40) together with cDNA clones we have obtained from a rat brain cDNA library (PRCM1,5,3 and 4). pRCM5 corresponds to 4.0 kb mRNA species observed primarily in skeletal muscle. These clones can be classified into three groups. They belong to three bona fide calmodulin genes with five to six exons called CaM I, CaM II and CaM III and four intronless retropseudogenes, one derived from CaM I and three derived from CaM II. We have not obtained retropseudogenes for CaM III so far. These three bona fide genes are transcribed into multiple sized mRNA species in a tissue-specific manner, that is, CaM I is ubiquitous, CaM II is transcribed mainly in brain and CaM III is transcribed primarily in brain and skeletal muscle. Four retropseudogenes do not appear to be transcribed. They are probably relics of inactivated genes. The physiological meanings of multiple calmodulin mRNA species and mechanisms of transcriptional regulation of these three bona fide genes will be the main subjects of our future experiments.
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Affiliation(s)
- H Nojima
- Department of Pharmacology, Jichi Medical School, Lochigi-ken, Japan
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38
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Chun M, Falkenthal S. Ifm(2)2 is a myosin heavy chain allele that disrupts myofibrillar assembly only in the indirect flight muscle of Drosophila melanogaster. J Biophys Biochem Cytol 1988; 107:2613-21. [PMID: 3144555 PMCID: PMC2115644 DOI: 10.1083/jcb.107.6.2613] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Using a combination of molecular and genetic techniques we demonstrate that Ifm(2)2 is an allele of the single-copy sarcomeric myosin heavy chain gene. Flies homozygous for this allele accumulate wild-type levels of mRNA and protein in tubular muscle of adults, but fail to accumulate detectable amounts of myosin heavy chain mRNA or protein in the indirect flight muscle. We propose that the mutation interferes with either transcription of the gene or splicing of the primary transcript in the indirect flight muscle and not in other muscle tissues. Biochemical and electron microscopic analysis of flies homozygous for this mutation has revealed that thick filament assembly is abolished in the indirect flight muscle resulting in the instability of wild-type thick filament proteins. In contrast, thin filament and Z disc assembly are marginally affected. We discuss a working hypothesis for sarcomere assembly and define and experimental approach to test the predictions of this proposed pathway for sarcomere assembly.
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Affiliation(s)
- M Chun
- Department of Molecular Genetics, Ohio State University, Columbus 43210
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39
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Arnold HH, Lohse P, Seidel U, Bober E. A novel human myosin alkali light chain is developmentally regulated. Expression in fetal cardiac and skeletal muscle and in adult atria. EUROPEAN JOURNAL OF BIOCHEMISTRY 1988; 178:53-60. [PMID: 2849544 DOI: 10.1111/j.1432-1033.1988.tb14428.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have isolated cDNA recombinant phages encoding the embryonic isoform of the myosin alkali light chain (MLC1emb) from a human fetal skeletal muscle library. The cDNA clones were detected by their weak cross-hybridization to a human MLC1F and MLC3F cDNA clone. Nucleotide sequence analysis of the complete cDNA (GT14) revealed an open reading frame for 197 amino acids. The derived protein sequence constitutes the first structural information on this myosin isoform of any organism. Remarkable structural similarities to other alkali MLC polypeptides, particularly to those of the slow-muscle type, are evident. Under conditions of high stringency, the GT14 clone hybridized to an abundant mRNA species in fetal ventricular muscle and adult atrial muscle, whereas in fetal skeletal muscle only a very weakly hybridizing mRNA component was detected. These mRNAs were indistinguishable by size and the thermal stability of their hybrids formed with the DNA insert of clone GT14. We therefore conclude that identical mRNA is expressed in these tissues, presumably transcribed from the same gene. According to its pattern of mRNA expression, the novel MLC isoform described here was designated as "embryonic and atrial myosin light chain" (MLC1emb/A) in reference to its developmental stage-specific and tissue-specific appearance in embryonic skeletal muscle, fetal ventricle and adult atrium.
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Affiliation(s)
- H H Arnold
- Department of Toxicology, Medical School, University of Hamburg, Federal Republic of Germany
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40
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Structure and sequence of the myosin alkali light chain gene expressed in adult cardiac atria and fetal striated muscle. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37805-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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41
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Perret C, Lomri N, Thomasset M. Evolution of the EF-hand calcium-binding protein family: evidence for exon shuffling and intron insertion. J Mol Evol 1988; 27:351-64. [PMID: 3146646 DOI: 10.1007/bf02101198] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The evolutionary history of the intracellular calcium-binding protein superfamily is well documented. The members of this gene family are all believed to be derived from a common ancestor, which, itself, was the product of two successive gene duplications. In this study, we have compared and analyzed the structures of the recently described genes coding for these proteins. We propose a series of evolutionary events, which include exon shuffling and intron insertion, that could account for the evolutionary origin of all the members of this superfamily. According to this hypothesis, the ancestral gene, a product of two successive duplications, consisted of at least four exons. Each exon coding for a peptide (a calcium-binding domain) was separated by an intron that had mediated the duplication. Each distinct lineage evolved from this ancestor by genomic rearrangement, with insertion of introns being a prominent feature.
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Affiliation(s)
- C Perret
- INSERM Unité 120, Le Vésinet, France
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42
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Beyer AL, Osheim YN. Splice site selection, rate of splicing, and alternative splicing on nascent transcripts. Genes Dev 1988; 2:754-65. [PMID: 3138163 DOI: 10.1101/gad.2.6.754] [Citation(s) in RCA: 441] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Based on ultrastructural analysis of actively transcribing genes seen in electron micrographs, we present evidence that pre-mRNA splicing occurs with a reasonable frequency on the nascent transcripts of early Drosophila embryo genes and that splice site selection may generally precede polyadenylation. The details of the process observed are in agreement with results from in vitro splicing systems but differ in the more rapid completion of in vivo splicing. For those introns that are removed cotranscriptionally, a series of events is initiated following 3' splice site synthesis, beginning with ribonucleoprotein (RNP) particle formation at the 3' splice site within 48 sec, intron loop formation within 2 min, and splicing within 3 min. The initiation of the process is correlated with 3' splice site synthesis but is independent of 5' splice site synthesis, the position of the intron within the transcript, and the age or length of the transcript. In some cases, introns are removed from the 5' end of a transcript before introns are synthesized at the 3' end, supporting a possible role for the order of transcription in splice site pairing. In general, our observations are consistent with the 'first-come-first-served' principle of splice site selection, although an observed example of exon skipping indicates that alternative splicing possibilities can be accommodated within this general framework.
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Affiliation(s)
- A L Beyer
- Department of Microbiology, University of Virginia School of Medicine, Charlottesville 22908
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43
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Dictyostelium discoideum myosin: isolation and characterization of cDNAs encoding the essential light chain. Mol Cell Biol 1988. [PMID: 2451126 DOI: 10.1128/mcb.8.2.794] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used an antibody specific for Dictyostelium discoideum myosin to screen a lambda gt11 cDNA expression library to obtain cDNA clones which encode the Dictyostelium essential myosin light chain (EMLC). The amino acid sequence predicted from the sequence of the cDNA clone showed 31.5% identity with the amino acid sequence of the chicken EMLC. Comparisons of the Dictyostelium EMLC, a nonmuscle cell type, with EMLC sequences from similar MLCs of skeletal- and smooth-muscle origin, showed distinct regions of homology. Much of the observed homology was localized to regions corresponding to consensus Ca2+-binding of E-F hand domains. Southern blot analysis suggested that the Dictyostelium genome contains a single gene encoding the EMLC. Examination of the pattern of EMLC mRNA expression showed that a significant increase in EMLC message levels occurred during the first few hours of development, coinciding with increased actin expression and immediately preceding the period of maximal chemotactic activity.
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44
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Green KJ, Goldman RD, Chisholm RL. Isolation of cDNAs encoding desmosomal plaque proteins: evidence that bovine desmoplakins I and II are derived from two mRNAs and a single gene. Proc Natl Acad Sci U S A 1988; 85:2613-7. [PMID: 3282232 PMCID: PMC280048 DOI: 10.1073/pnas.85.8.2613] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Desmoplakins (DPs) I and II (approximately equal to 240 and approximately equal to 210 kDa) are major components of the internal portion of the desmosomal cytoplasmic plaque. Desmosomes play a crucial role in cell-cell adhesion and serve as specific attachment sites for cytoplasmic intermediate filaments. Although DP-I and -II are closely related molecules, their structure (i.e., amino acid or DNA sequence) has not been determined. In addition, it is not known whether these proteins are derived from one or more genes or whether they result from posttranscriptional or posttranslational events. This paper describes the isolation and characterization of eight DP cDNA clones from a bovine lambda gt11 expression library. Fusion proteins from six of these clones selected antibodies that reacted with DP-I and -II and two selected antibodies that reacted with DP-I alone. Antibodies made against fusion protein produced by the DP1A clone reacted specifically with DP-I and -II on immunoblots. When used for indirect immunofluorescence on bovine tongue cryostat sections and cultured mouse keratinocytes, these antibodies produced a typical desmosomal staining pattern. RNA blot analysis demonstrated hybridization of three DP-I/II cDNA probes with two messages of approximately equal to 7.5 and approximately equal to 9.5 kilobases in bovine tongue RNA. In contrast, a cDNA clone that affinity-purified antibodies reacting with DP-I only hybridized exclusively with the 9.5-kilobase band. Southern blots of genomic DNA digested with a panel of restriction enzymes were hybridized with one probe derived from a DP-I/II clone and with one from a DP-I clone. Both probes hybridized with single bands of the same size in each digested sample of DNA. Together, these data suggest that DP-I and DP-II are translated from two separate messages in bovine tongue and that these messages may be derived from a single gene.
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Affiliation(s)
- K J Green
- Department of Pathology, Northwestern University Medical School, Chicago, IL 60611
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Chisholm RL, Rushforth AM, Pollenz RS, Kuczmarski ER, Tafuri SR. Dictyostelium discoideum myosin: isolation and characterization of cDNAs encoding the essential light chain. Mol Cell Biol 1988; 8:794-801. [PMID: 2451126 PMCID: PMC363206 DOI: 10.1128/mcb.8.2.794-801.1988] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We used an antibody specific for Dictyostelium discoideum myosin to screen a lambda gt11 cDNA expression library to obtain cDNA clones which encode the Dictyostelium essential myosin light chain (EMLC). The amino acid sequence predicted from the sequence of the cDNA clone showed 31.5% identity with the amino acid sequence of the chicken EMLC. Comparisons of the Dictyostelium EMLC, a nonmuscle cell type, with EMLC sequences from similar MLCs of skeletal- and smooth-muscle origin, showed distinct regions of homology. Much of the observed homology was localized to regions corresponding to consensus Ca2+-binding of E-F hand domains. Southern blot analysis suggested that the Dictyostelium genome contains a single gene encoding the EMLC. Examination of the pattern of EMLC mRNA expression showed that a significant increase in EMLC message levels occurred during the first few hours of development, coinciding with increased actin expression and immediately preceding the period of maximal chemotactic activity.
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Affiliation(s)
- R L Chisholm
- Department of Cell Biology and Anatomy, Northwestern University Medical School, Chicago, Illinois 60611
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46
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47
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Goodwin EB, Szent-Gyorgyi AG, Leinwand LA. Cloning and characterization of the scallop essential and regulatory myosin light chain cDNAs. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)60925-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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48
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Nabeshima Y, Nabeshima Y, Nonomura Y, Fujii-Kuriyama Y. Nonmuscle and smooth muscle myosin light chain mRNAs are generated from a single gene by the tissue-specific alternative RNA splicing. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61006-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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49
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O'Sullivan DM, Noonan D, Quaranta V. Four Ia invariant chain forms derive from a single gene by alternate splicing and alternate initiation of transcription/translation. J Exp Med 1987; 166:444-60. [PMID: 3036998 PMCID: PMC2189580 DOI: 10.1084/jem.166.2.444] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We determined the structural basis for the presence of electrophoretically-distinct, antigenically-related forms of invariant chains in Ia oligomers, and established the mechanisms by which they can be expressed from a single gene. S1 nuclease protection assays indicated that, in B cells, transcription of this gene initiates at a minimum of three sites. Thus, unlike previously thought, invariant chain mRNAs have heterogeneous 5' untranslated segments that may differentially affect initiation of translation. Further, restriction mapping and nucleotide sequencing of cDNAs revealed two kinds of invariant chain mRNAs differing by an internal coding segment of 192 bp. This segment represents an alternatively spliced exon, as demonstrated by nucleotide sequencing of corresponding genomic regions. The exon (exon X) encodes a cysteine-rich stretch of 64 amino acids near the COOH terminus that displays a striking and surprising homology to an internal amino acid repeat of thyroglobulin, suggesting an evolutionary mechanism of exon shuffling. Transient expression of cDNAs indicated that both types of alternatively spliced mRNAs contain two in-frame AUGs functioning as alternate start sites for translation. Thus, transfections with exon X-lacking cDNAs resulted in the expression of Mr 33,000 and 31,000 proteins, detected by immunoprecipitation with anti-invariant chain antisera, and identical by two-dimensional gel (2-D) analyses to the B cell invariant-chain forms gamma 1 (Mr 31,000), gamma 2, and gamma 3 (Mr 33,000). Similarly, exon X-containing cDNAs expressed Mr 43,000 and 41,000 proteins, also identical by 2-D migration to Ia-associated proteins. Thus, human Ia molecules contain four forms of invariant chain of closely related but nonidentical primary structure that are generated from a single gene by a complex pattern of alternate transcriptional start, exon splicing, and translational start.
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50
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Lew AM, McCluskey J, Maloy WL, Margulies DH, Coligan JE. Multiple class I molecules generated from single genes by alternative splicing of pre-mRNAs. Immunol Res 1987; 6:117-32. [PMID: 2442272 DOI: 10.1007/bf02918108] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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