scholarly journals Myotonia-related mutations in the distal C-terminus of ClC-1 and ClC-0 chloride channels affect the structure of a poly-proline helix

2007 ◽  
Vol 403 (1) ◽  
pp. 79-87 ◽  
Author(s):  
María J. Macías ◽  
Oscar Teijido ◽  
Giovanni Zifarelli ◽  
Pau Martin ◽  
Ximena Ramirez-Espain ◽  
...  
Keyword(s):  
Chloride Channels ◽  
Structural Changes ◽  
Surface Expression ◽  
Muscle Fibres ◽  
Coding Region ◽  
Protein Coding ◽  
C Terminus ◽  
Voltage Dependent ◽  
Common Gate ◽  
Spectroscopy Studies

Myotonia is a state of hyperexcitability of skeletal-muscle fibres. Mutations in the ClC-1 Cl− channel cause recessive and dominant forms of this disease. Mutations have been described throughout the protein-coding region, including three sequence variations (A885P, R894X and P932L) in a distal C-terminal stretch of residues [CTD (C-terminal domain) region] that are not conserved between CLC proteins. We show that surface expression of these mutants is reduced in Xenopus oocytes compared with wild-type ClC-1. Functional, biochemical and NMR spectroscopy studies revealed that the CTD region encompasses a segment conserved in most voltage-dependent CLC channels that folds with a secondary structure containing a short type II poly-proline helix. We found that the myotonia-causing mutation A885P disturbs this structure by extending the poly-proline helix. We hypothesize that this structural modification results in the observed alteration of the common gate that acts on both pores of the channel. We provide the first experimental investigation of structural changes resulting from myotonia-causing mutations.

scholarly journals Different Domains of Phytophthora sojae Effector Avr4/6 Are Recognized by Soybean Resistance Genes Rps4 and Rps6

2010 ◽  
Vol 23 (4) ◽  
pp. 425-435 ◽  
Author(s):  
Daolong Dou ◽  
Shiv D. Kale ◽  
Tingli Liu ◽  
Qinghua Tang ◽  
Xia Wang ◽  
...  
Keyword(s):  
Protein Translocation ◽  
Single Gene ◽  
Phytophthora Sojae ◽  
Avirulence Genes ◽  
Coding Region ◽  
Nucleotide Substitutions ◽  
Protein Coding ◽  
C Terminus ◽  
Oomycete Pathogen ◽  
Soybean Leaves

At least 12 avirulence genes have been genetically identified and mapped in Phytophthora sojae, an oomycete pathogen causing root and stem rot of soybean. Previously, the Avr4 and Avr6 genes of P. sojae were genetically mapped within a 24 kb interval of the genome. Here, we identify Avr4 and Avr6 and show that they are actually a single gene, Avr4/6, located near the 24-kb region. Avr4/6 encodes a secreted protein of 123 amino acids with an RXLR-dEER protein translocation motif. Transient expression of Avr4/6 in soybean leaves revealed that its gene product could trigger a hypersensitive response (HR) in the presence of either Rps4 or Rps6. Silencing Avr4/6 in P. sojae stable transformants abolished the avirulence phenotype exhibited on both Rps4 and Rps6 soybean cultivars. The N terminus of Avr4/6, including the dEER motif, is sufficient to trigger Rps4-dependent HR while its C terminus is sufficient to trigger Rps6-mediated HR. Compared with alleles from avirulent races, alleles of Avr4/6 from virulent races possess nucleotide substitutions in the 5′ untranslated region of the gene but not in the protein-coding region.

scholarly journals Structure of transcripts from the homeotic Antennapedia gene of Drosophila melanogaster: two promoters control the major protein-coding region.

1986 ◽  
Vol 6 (12) ◽  
pp. 4676-4689 ◽  
Author(s):  
A Laughon ◽  
A M Boulet ◽  
J R Bermingham ◽  
R A Laymon ◽  
M P Scott
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Polyadenylation ◽  
Transcription Unit ◽  
Cdna Clones ◽  
Major Protein ◽  
Coding Region ◽  
Developmentally Regulated ◽  
Protein Coding ◽  
Reading Frame ◽  
C Terminus

The Antennapedia (Antp) homeotic gene of Drosophila melanogaster regulates segmental identity in the thorax. Loss of Antp function results in altered development of the embryonic thoracic segments or can cause legs to be transformed into antennae. Certain combinations of Antp recessive lethal alleles complement to permit normal development. The structure of the Antp gene, analyzed by sequencing cDNA clones and exons and by transcript mapping, revealed some of the basis for its genetic complexity. It has two promoters governing two nested transcription units, one unit 36 and one 103 kilobase pairs (kb) long. Both units incorporated the same protein-coding exons, all of which are located in the 3'-most 13 kb of the gene. The two promoters resulted in the attachment of either of two long noncoding leader sequences (1.5 and 1.7 kb) to a 1.1-kb open reading frame. Both transcription units used the same pair of alternative polyadenylation sites 1.4 kb apart; the choice of sites was developmentally regulated. Some of the mutations that disrupt the larger transcription unit complemented a mutation affecting the smaller one. Dominant mutations that transform antennae into legs split the gene but left the coding exons intact. The encoded protein has unusually long runs of glutamine and a homeodomain near the C terminus.

Structure of transcripts from the homeotic Antennapedia gene of Drosophila melanogaster: two promoters control the major protein-coding region

1986 ◽  
Vol 6 (12) ◽  
pp. 4676-4689
Author(s):  
A Laughon ◽  
A M Boulet ◽  
J R Bermingham ◽  
R A Laymon ◽  
M P Scott
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Polyadenylation ◽  
Transcription Unit ◽  
Cdna Clones ◽  
Major Protein ◽  
Coding Region ◽  
Developmentally Regulated ◽  
Protein Coding ◽  
Reading Frame ◽  
C Terminus

The Antennapedia (Antp) homeotic gene of Drosophila melanogaster regulates segmental identity in the thorax. Loss of Antp function results in altered development of the embryonic thoracic segments or can cause legs to be transformed into antennae. Certain combinations of Antp recessive lethal alleles complement to permit normal development. The structure of the Antp gene, analyzed by sequencing cDNA clones and exons and by transcript mapping, revealed some of the basis for its genetic complexity. It has two promoters governing two nested transcription units, one unit 36 and one 103 kilobase pairs (kb) long. Both units incorporated the same protein-coding exons, all of which are located in the 3'-most 13 kb of the gene. The two promoters resulted in the attachment of either of two long noncoding leader sequences (1.5 and 1.7 kb) to a 1.1-kb open reading frame. Both transcription units used the same pair of alternative polyadenylation sites 1.4 kb apart; the choice of sites was developmentally regulated. Some of the mutations that disrupt the larger transcription unit complemented a mutation affecting the smaller one. Dominant mutations that transform antennae into legs split the gene but left the coding exons intact. The encoded protein has unusually long runs of glutamine and a homeodomain near the C terminus.

scholarly journals Gating the glutamate gate of CLC-2 chloride channel by pore occupancy

2015 ◽  
Vol 147 (1) ◽  
pp. 25-37 ◽  
Author(s):  
José J. De Jesús-Pérez ◽  
Alejandra Castro-Chong ◽  
Ru-Chi Shieh ◽  
Carmen Y. Hernández-Carballo ◽  
José A. De Santiago-Castillo ◽  
...  
Keyword(s):  
Chloride Channels ◽  
Side Chain ◽  
Minor Role ◽  
Transmembrane Voltage ◽  
Voltage Dependent ◽  
Cytosolic Side ◽  
Common Gate ◽  
Pore Occupancy ◽  
A Minor ◽  
Inside Out

CLC-2 channels are dimeric double-barreled chloride channels that open in response to hyperpolarization. Hyperpolarization activates protopore gates that independently regulate the permeability of the pore in each subunit and the common gate that affects the permeability through both pores. CLC-2 channels lack classic transmembrane voltage–sensing domains; instead, their protopore gates (residing within the pore and each formed by the side chain of a glutamate residue) open under repulsion by permeant intracellular anions or protonation by extracellular H+. Here, we show that voltage-dependent gating of CLC-2: (a) is facilitated when permeant anions (Cl−, Br−, SCN−, and I−) are present in the cytosolic side; (b) happens with poorly permeant anions fluoride, glutamate, gluconate, and methanesulfonate present in the cytosolic side; (c) depends on pore occupancy by permeant and poorly permeant anions; (d) is strongly facilitated by multi-ion occupancy; (e) is absent under likely protonation conditions (pHe = 5.5 or 6.5) in cells dialyzed with acetate (an impermeant anion); and (f) was the same at intracellular pH 7.3 and 4.2; and (g) is observed in both whole-cell and inside-out patches exposed to increasing [Cl−]i under unlikely protonation conditions (pHe = 10). Thus, based on our results we propose that hyperpolarization activates CLC-2 mainly by driving intracellular anions into the channel pores, and that protonation by extracellular H+ plays a minor role in dislodging the glutamate gate.

Ion channels and G protein-coupled receptors as targets for invertebrate pest control: from past challenges to practical insecticides

2021 ◽  
Author(s):  
Yoshihisa Ozoe
Keyword(s):  
Ion Channels ◽  
G Protein ◽  
Pest Control ◽  
Gaba Receptors ◽  
Chloride Channels ◽  
Structural Changes ◽  
G Protein Coupled Receptors ◽  
Octopamine Receptors ◽  
Sites Of Action ◽  
G Protein Coupled

Abstract In the late 1970s, we discovered that toxic bicyclic phosphates inhibit the generation of miniature inhibitory junction potentials, implying their antagonism of γ-aminobutyric acid (GABA) receptors (GABARs; GABA-gated chloride channels). This unique mode of action provided a strong incentive for our research on GABARs in later years. Furthermore, minor structural changes conferred insect GABAR selectivity to this class of compounds, convincing us of the possibility of GABARs as targets for insecticides. Forty years later, third-generation insecticides acting as allosteric modulator antagonists at a distinctive site of action in insect GABARs were developed. G protein-coupled receptors (GPCRs) are also promising targets for pest control. We characterized phenolamine receptors functionally and pharmacologically. Of the tested receptors, β-adrenergic-like octopamine receptors were revealed to be the most sensitive to the acaricide/insecticide amitraz. Given the presence of multiple sites of action, ion channels and GPCRs remain potential targets for invertebrate pest control.

Selection on Rapidly Evolving Proteins in the Arabidopsis Genome

Genetics ◽  
2003 ◽  
Vol 163 (2) ◽  
pp. 723-733 ◽  
Author(s):  
Marianne Barrier ◽  
Carlos D Bustamante ◽  
Jiaye Yu ◽  
Michael D Purugganan
Keyword(s):  
Expressed Sequence Tag ◽  
Amino Acid Replacement ◽  
Adaptive Divergence ◽  
Coding Region ◽  
Protein Coding ◽  
Hierarchical Bayesian Analysis ◽  
Brassicaceae Species ◽  
Replacement Site ◽  
Orthologous Loci ◽  
Selection Intensities

Abstract Genes that have undergone positive or diversifying selection are likely to be associated with adaptive divergence between species. One indicator of adaptive selection at the molecular level is an excess of amino acid replacement fixed differences per replacement site relative to the number of synonymous fixed differences per synonymous site (ω = Ka/Ks). We used an evolutionary expressed sequence tag (EST) approach to estimate the distribution of ω among 304 orthologous loci between Arabidopsis thaliana and A. lyrata to identify genes potentially involved in the adaptive divergence between these two Brassicaceae species. We find that 14 of 304 genes (∼5%) have an estimated ω > 1 and are candidates for genes with increased selection intensities. Molecular population genetic analyses of 6 of these rapidly evolving protein loci indicate that, despite their high levels of between-species nonsynonymous divergence, these genes do not have elevated levels of intraspecific replacement polymorphisms compared to previously studied genes. A hierarchical Bayesian analysis of protein-coding region evolution within and between species also indicates that the selection intensities of these genes are elevated compared to previously studied A. thaliana nuclear loci.

scholarly journals Influence of the Leader protein coding region of foot-and-mouth disease virus on virus replication

2013 ◽  
Vol 94 (7) ◽  
pp. 1486-1495 ◽  
Author(s):  
Graham J. Belsham
Keyword(s):  
Disease Virus ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Initiation Codon ◽  
Coding Region ◽  
Protein Coding ◽  
Coding Sequence ◽  
Bhk Cells ◽  
Leader Protein ◽  
Mouth Disease Virus

The foot-and-mouth disease virus (FMDV) Leader (L) protein is produced in two forms, Lab and Lb, differing only at their amino-termini, due to the use of separate initiation codons, usually 84 nt apart. It has been shown previously, and confirmed here, that precise deletion of the Lab coding sequence is lethal for the virus, whereas loss of the Lb coding sequence results in a virus that is viable in BHK cells. In addition, it is now shown that deletion of the ‘spacer’ region between these two initiation codons can be tolerated. Growth of the virus precisely lacking just the Lb coding sequence resulted in a previously undetected accumulation of frameshift mutations within the ‘spacer’ region. These mutations block the inappropriate fusion of amino acid sequences to the amino-terminus of the capsid protein precursor. Modification, by site-directed mutagenesis, of the Lab initiation codon, in the context of the virus lacking the Lb coding region, was also tolerated by the virus within BHK cells. However, precise loss of the Lb coding sequence alone blocked FMDV replication in primary bovine thyroid cells. Thus, the requirement for the Leader protein coding sequences is highly dependent on the nature and extent of the residual Leader protein sequences and on the host cell system used. FMDVs precisely lacking Lb and with the Lab initiation codon modified may represent safer seed viruses for vaccine production.

Human DNA sequences homologous to a protein coding region conserved between homeotic genes of Drosophila

Cell ◽  
1984 ◽  
Vol 38 (3) ◽  
pp. 667-673 ◽  
Author(s):  
Michael Levine ◽  
Gerald M. Rubin ◽  
Robert Tjian
Keyword(s):  
Dna Sequences ◽  
Homeotic Genes ◽  
Coding Region ◽  
Protein Coding ◽  
Human Dna

scholarly journals An additional promoter within the protein-coding region of thepsbD-psbC gene cluster in tobacco chloroplast DNA

1989 ◽  
Vol 17 (23) ◽  
pp. 9583-9591 ◽  
Author(s):  
Wen Biao Yao ◽  
Bing Yuan Meng ◽  
Minoru Tanaka ◽  
Masahiro Sugiura
Keyword(s):  
Chloroplast Dna ◽  
Gene Cluster ◽  
Coding Region ◽  
Protein Coding ◽  
Tobacco Chloroplast
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