scholarly journals Identification of Human Astrovirus Genome-Linked Protein (VPg) Essential for Virus Infectivity

2012 ◽  
Vol 86 (18) ◽  
pp. 10070-10078 ◽  
Author(s):  
Cristina Fuentes ◽  
Albert Bosch ◽  
Rosa M. Pintó ◽  
Susana Guix
Keyword(s):  
Rna Virus ◽  
Sequence Similarity ◽  
Amino Acid Sequence Similarity ◽  
Virus Infectivity ◽  
Coding Region ◽  
Content Type ◽  
Reading Frame ◽  
High Amino Acid ◽  
Human Astrovirus ◽  
Experimental Findings

Viral genome-linked proteins (VPgs) have been identified in several single-stranded positive-sense RNA virus families. The presence of such protein in the familyAstroviridaehas not been fully elucidated, although a putative VPg coding region in open reading frame 1a (ORF1a) of astrovirus with high amino acid sequence similarity to the VPg coding region ofCaliciviridaehas been previously identified. In this work we present several experimental findings that show that human astrovirus (HAstV) RNA encodes a VPg essential for viral infectivity: (i) RNase treatment of RNA purified from astrovirus-infected cells results in a single protein of 13 to 15 kDa, compatible with the predicted astrovirus VPg size; (ii) the antibody used to detect this 13- to 15-kDa protein is specifically directed against a region that includes the putative VPg coding region; (iii) the 13- to 15-kDa protein detected has been partially sequenced and the sequence obtained is contained in the computationally predicted VPg; (iv) the protein resulting from this putative VPg coding region is a highly disordered protein, resembling the VPg of sobemo-, calici- and potyviruses; (v) proteolytic treatment of the genomic RNA leads to loss of infectivity; and (vi) mutagenesis of Tyr-693 included in the putative VPg protein is lethal for HAstV replication, which strongly supports its functional role in the covalent link with the viral RNA.

scholarly journals NrdH Redoxin Enhances Resistance to Multiple Oxidative Stresses by Acting as a Peroxidase Cofactor in Corynebacterium glutamicum

2013 ◽  
Vol 80 (5) ◽  
pp. 1750-1762 ◽  
Author(s):  
Mei-Ru Si ◽  
Lei Zhang ◽  
Zhi-Fang Yang ◽  
Yi-Xiang Xu ◽  
Ying-Bao Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Corynebacterium Glutamicum ◽  
Sequence Similarity ◽  
Thioredoxin Reductase ◽  
Amino Acid Sequence Similarity ◽  
Content Type ◽  
Reduction Activity ◽  
Oxidative Stresses ◽  
High Amino Acid ◽  
Thiol Peroxidase

ABSTRACTNrdH redoxins are small protein disulfide oxidoreductases behaving like thioredoxins but sharing a high amino acid sequence similarity to glutaredoxins. Although NrdH redoxins are supposed to be another candidate in the antioxidant system, their physiological roles in oxidative stress remain unclear. In this study, we confirmed that theCorynebacterium glutamicumNrdH redoxin catalytically reduces the disulfides in the class Ib ribonucleotide reductases (RNR), insulin and 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB), by exclusively receiving electrons from thioredoxin reductase. Overexpression of NrdH increased the resistance ofC. glutamicumto multiple oxidative stresses by reducing ROS accumulation. Accordingly, elevated expression of thenrdHgene was observed when theC. glutamicumwild-type strain was exposed to oxidative stress conditions. It was discovered that the NrdH-mediated resistance to oxidative stresses was largely dependent on the presence of the thiol peroxidase Prx, as the increased resistance to oxidative stresses mediated by overexpression of NrdH was largely abrogated in theprxmutant. Furthermore, we showed that NrdH facilitated the hydroperoxide reduction activity of Prx by directly targeting and serving as its electron donor. Thus, we present evidence that the NrdH redoxin can protect against the damaging effects of reactive oxygen species (ROS) induced by various exogenous oxidative stresses by acting as a peroxidase cofactor.

scholarly journals Klebsiella Phage ΦK64-1 Encodes Multiple Depolymerases for Multiple Host Capsular Types

2017 ◽  
Vol 91 (6) ◽  
Author(s):  
Yi-Jiun Pan ◽  
Tzu-Lung Lin ◽  
Ching-Ching Chen ◽  
Yun-Ting Tsai ◽  
Yi-Hsiang Cheng ◽  
...  
Keyword(s):  
Sequence Similarity ◽  
Amino Acid Sequence Similarity ◽  
Gene Products ◽  
Capsular Type ◽  
Expression And Purification ◽  
Content Type ◽  
Infection Mechanisms ◽  
Host Infection ◽  
Encoding Genes ◽  
Tail Fibers

ABSTRACT The genome of the multihost bacteriophage ΦK64-1, capable of infecting Klebsiella capsular types K1, K11, K21, K25, K30, K35, K64, and K69, as well as new capsular types KN4 and KN5, was analyzed and revealed that 11 genes (S1-1, S1-2, S1-3, S2-1, S2-2, S2-3, S2-4, S2-5, S2-6, S2-7, and S2-8) encode proteins with amino acid sequence similarity to tail fibers/spikes or lyases. S2-5 previously was shown to encode a K64 capsule depolymerase (K64dep). Specific capsule-degrading activities of an additional eight putative capsule depolymerases (S2-4 against K1, S1-1 against K11, S1-3 against K21, S2-2 against K25, S2-6 against K30/K69, S2-3 against K35, S1-2 against KN4, and S2-1 against KN5) was demonstrated by expression and purification of the recombinant proteins. Consistent with the capsular type-specific depolymerization activity of these gene products, phage mutants of S1-2, S2-2, S2-3, or S2-6 lost infectivity for KN4, K25, K35, or K30/K69, respectively, indicating that capsule depolymerase is crucial for infecting specific hosts. In conclusion, we identified nine functional capsule depolymerase-encoding genes in a bacteriophage and correlated activities of the gene products to all ten hosts of this phage, providing an example of type-specific host infection mechanisms in a multihost bacteriophage. IMPORTANCE We currently identified eight novel capsule depolymerases in a multihost Klebsiella bacteriophage and correlated the activities of the gene products to all hosts of this phage, providing an example of carriage of multiple depolymerases in a phage with a wide capsular type host spectrum. Moreover, we also established a recombineering system for modification of Klebsiella bacteriophage genomes and demonstrated the importance of capsule depolymerase for infecting specific hosts. Based on the powerful tool for modification of phage genome, further studies can be conducted to improve the understanding of mechanistic details of Klebsiella phage infection. Furthermore, the newly identified capsule depolymerases will be of great value for applications in capsular typing.

scholarly journals The Two Drosophila Telomeric Transposable Elements Have Very Different Patterns of Transcription

1999 ◽  
Vol 19 (1) ◽  
pp. 873-881 ◽  
Author(s):  
O. N. Danilevskaya ◽  
K. L. Traverse ◽  
N. C. Hogan ◽  
P. G. DeBaryshe ◽  
M. L. Pardue
Keyword(s):  
Transposable Elements ◽  
Sequence Similarity ◽  
Sequence Divergence ◽  
Full Length ◽  
Coding Region ◽  
Free Standing ◽  
Reading Frame ◽  
Sequence Organization ◽  
Sense Strand ◽  
Cell Fractions

ABSTRACT The transposable elements HeT-A and TARTconstitute the telomeres of Drosophila chromosomes. Both are non-long terminal repeat (LTR) retrotransposons, sharing the remarkable property of transposing only to chromosome ends. In addition, strong sequence similarity of their gag proteins indicates that these coding regions share a common ancestor. These findings led to the assumption that HeT-A andTART are closely related. However, we now find that these elements produce quite different sets of transcripts. HeT-Aproduces only sense-strand transcripts of the full-length element, whereas TART produces both sense and antisense full-length RNAs, with antisense transcripts in more than 10-fold excess over sense RNA. In addition, features of TART sequence organization resemble those of a subclass of non-LTR elements characterized by unequal terminal repeats. Thus, the ancestral gag sequence appears to have become incorporated in two different types of elements, possibly with different functions in the telomere. HeT-Atranscripts are found in both nuclear and cytoplasmic cell fractions, consistent with roles as both mRNA and transposition template. In contrast, both sense and antisense TART transcripts are almost entirely concentrated in nuclear fractions. Also,TART open reading frame 2 probes detect a cytoplasmic mRNA for reverse transcriptase (RT), with no similarity to TARTsequence 5′ or 3′ of the RT coding region. This RNA could be a processed TART transcript or the product of a “free-standing” RT gene. Either origin would be novel. The distinctive transcription patterns of both HeT-A andTART are conserved in Drosophila yakuba, despite significant sequence divergence. The conservation argues that these sets of transcripts are important to the function(s) ofHeT-A and TART.

scholarly journals pH-dependent regulation of the multi-subunit cation/proton antiporter Pha1 system from Sinorhizobium meliloti

Microbiology ◽  
2009 ◽  
Vol 155 (8) ◽  
pp. 2750-2756 ◽  
Author(s):  
Toshio Yamaguchi ◽  
Fuminori Tsutsumi ◽  
Péter Putnoky ◽  
Masahiro Fukuhara ◽  
Tatsunosuke Nakamura
Keyword(s):  
Sinorhizobium Meliloti ◽  
Sequence Similarity ◽  
Plant Root ◽  
Functional Expression ◽  
Amino Acid Sequence Similarity ◽  
Ph Optimum ◽  
Cation Selectivity ◽  
High Amino Acid ◽  
Alkaline Conditions ◽  
Ph Dependent

The pha1 gene cluster (pha1A′-G) of Sinorhizobium meliloti has previously been characterized as a necessary component for proper invasion into plant root tissue. It has been suggested to encode a multi-subunit K+/H+ antiporter, since mutations in the pha1 region rendered S. meliloti cells sensitive to K+ and alkali, and because there is high amino acid sequence similarity to previously characterized multi-subunit cation/H+ antiporters (Mrp antiporters). However, the detailed transport properties of the Pha1 system are yet to be determined. Interestingly, most of the Mrp antiporters are highly selective for Na+, unlike the Pha1 system. Here, we report the functional expression of the Pha1 system in Escherichia coli and the measurement of cation/H+ antiport activity. We showed that the Pha1 system is indeed a K+/H+ antiporter with a pH optimum under mildly alkaline conditions. Moreover, we found that the Pha1 system can transport Na+; this was unexpected based on previous phenotypic analyses of pha1 mutants. Furthermore, we demonstrated that the cation selectivity of the Pha1 system was altered when the pH was lowered from the optimum. The downregulation of Na+/H+ and K+/H+ antiport activities upon acidic shift appeared to occur via different processes, which might indicate the presence of distinct mechanisms for the regulation of the K+/H+ and Na+/H+ antiport activities of the Pha1 system.

scholarly journals Identification and Characterization of a NaCl-Responsive Genetic Locus Involved in Survival during Desiccation in Sinorhizobium meliloti

2013 ◽  
Vol 79 (18) ◽  
pp. 5693-5700 ◽  
Author(s):  
Jan A. C. Vriezen ◽  
Frans J. de Bruijn ◽  
Klaus Nüsslein
Keyword(s):  
Sinorhizobium Meliloti ◽  
Agricultural Soils ◽  
Sequence Similarity ◽  
Genetic Locus ◽  
Model Organism ◽  
Normal Growth ◽  
Growth Conditions ◽  
Amino Acid Sequence Similarity ◽  
Content Type ◽  
Genetic Mechanisms

ABSTRACTTheRhizobiaceaeare a bacterial family of enormous agricultural importance due to the ability of its members to fix atmospheric nitrogen in an intimate relationship with plants. Their survival as naturally occurring soil bacteria in agricultural soils as well as popular seed inocula is affected directly by drought and salinity. Survival after desiccation in the presence of NaCl is enabled by underlying genetic mechanisms in the model organismSinorhizobium meliloti1021. Since salt stress parallels a loss in water activity, the identification of NaCl-responsive loci may identify loci involved in survival during desiccation. This approach enabled identification of the lociasnOandnggby their reduced ability to grow on increased NaCl concentrations, likely due to their inability to produce the osmoprotectant N-acetylglutaminylglutamine (NAGGN). In addition, the mutant harboringngg::Tn5luxABwas affected in its ability to survive desiccation and responded to osmotic stress. The desiccation sensitivity may have been due to secondary functions of Ngg (N-acetylglutaminylglutamine synthetase)-like cell wall metabolism as suggested by the presence of ad-alanine-d-alanine ligase (dAla-dAla) domain and by sensitivity of the mutant to β-lactam antibiotics.asnO::Tn5luxABis expressed during the stationary phase under normal growth conditions. Amino acid sequence similarity to enzymes producing β-lactam inhibitors and increased resistance to β-lactam antibiotics may indicate thatasnOis involved in the production of a β-lactam inhibitor.

scholarly journals Inhibition of mitogen-activated protein kinase by a Drosophila dual-specific phosphatase

2000 ◽  
Vol 349 (3) ◽  
pp. 821-828 ◽  
Author(s):  
Won-Jae LEE ◽  
Sun-Hong KIM ◽  
Yong-Sik KIM ◽  
Sung-Jun HAN ◽  
Ki-Sook PARK ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Kinase ◽  
Expressed Sequence Tag ◽  
Mapk Pathway ◽  
Sequence Similarity ◽  
Mitogen Activated Protein Kinase ◽  
Amino Acid Sequence Similarity ◽  
Calculated Molecular Mass ◽  
High Amino Acid ◽  
Mitogen Activated Protein

The Drosophila extracellular signal-regulated kinase (DERK) mitogen-activated protein kinase (MAPK) is involved in the regulation of multiple differentiation and developmental processes. Tight control of MAPK activity is critical for normal cell behaviour. We identified a novel Drosophila MAPK phosphatase (DMKP) cDNA from the expressed-sequence-tag database and characterized it. Analysis of the nucleotide sequence revealed an open reading frame encoding the 203-amino acid protein, with a calculated molecular mass of 23kDa, which has a high amino acid sequence similarity with ‘VH1-like’dual-specific phosphatases at the broad region near the catalytic sites. The expression of DMKP mRNA occurs from the late larval stages to adulthood in Drosophila development. The recombinant DMKP protein produced in yeast retained its phosphatase activity. When expressed in Schneider cells, DMKP dose-dependently inhibited DERK and Drosophila c-Jun N-terminal kinase activities with high selectivity towards DERK. However, DMKP did not have any affect on Drosophila p38 activity. When DMKP was expressed in yeast, it down-regulated the fus1-lacZ trans-reporter gene of the pheromone MAPK pathway without any significant effect on the high-osmolarity-glycerol-response pathway.

scholarly journals Programmed Translational Frameshift in the Bacteriophage P2 FETUD Tail Gene Operon

2002 ◽  
Vol 184 (23) ◽  
pp. 6522-6531 ◽  
Author(s):  
Gail E. Christie ◽  
Louise M. Temple ◽  
Becky A. Bartlett ◽  
Tina S. Goodwin
Keyword(s):  
Gene Cluster ◽  
Sequence Similarity ◽  
Initiation Site ◽  
Translation Initiation Site ◽  
Amino Acid Sequence Similarity ◽  
Reading Frame ◽  
Coding Regions ◽  
Translational Frameshift ◽  
Bacteriophage P2 ◽  
Contractile Tail

ABSTRACT The major structural components of the P2 contractile tail are encoded in the FETUD tail gene operon. The sequences of genes F I and F II, encoding the major tail sheath and tail tube proteins, have been reported previously (L. M. Temple, S. L. Forsburg, R. Calendar, and G. E. Christie, Virology 181:353-358, 1991). Sequence analysis of the remainder of this operon and the locations of amber mutations Eam30, Tam5, Tam64, Tam215, Uam25, Uam77, Uam92, and Dam6 and missense mutation Ets55 identified the coding regions for genes E, T, U, and D, completing the sequence determination of the P2 genome. Inspection of the DNA sequence revealed a new open reading frame overlapping the end of the essential tail gene E. Lack of an apparent translation initiation site and identification of a putative sequence for a programmed translational frameshift within the E gene suggested that this new reading frame (E′) might be translated as an extension of gene E, following a −1 translational frameshift. Complementation analysis demonstrated that E′ was essential for P2 lytic growth. Analysis of fusion polypeptides verified that this reading frame was translated as a −1 frameshift extension of gpE, with a frequency of approximately 10%. The arrangement of these two genes within the tail gene cluster of phage P2 and their coupling via a translational frameshift appears to be conserved among P2-related phages. This arrangement shows a striking parallel to the organization in the tail gene cluster of phage lambda, despite a lack of amino acid sequence similarity between the tail gene products of these phage families.

scholarly journals AdeR, a PucR-Type Transcription Factor, Activates Expression of l-Alanine Dehydrogenase and Is Required for Sporulation of Bacillus subtilis

2012 ◽  
Vol 194 (18) ◽  
pp. 4995-5001 ◽  
Author(s):  
Ta-Hui Lin ◽  
Guei-Tsung Wei ◽  
Chien-Chen Su ◽  
Gwo-Chyuan Shaw
Keyword(s):  
Bacillus Subtilis ◽  
Inverted Repeat ◽  
Sequence Similarity ◽  
Initiation Site ◽  
Amino Acid Sequence Similarity ◽  
Mobility Shift ◽  
Transcriptional Initiation ◽  
Transcription Terminator ◽  
Content Type ◽  
Alanine Dehydrogenase

ABSTRACTTheBacillus subtilis aldgene encodesl-alanine dehydrogenase, which catalyzes the NAD+-dependent deamination ofl-alanine to pyruvate for the generation of energy and is required for normal sporulation. The transcription ofaldis induced by alanine, but the mechanism underlying alanine induction remains unknown. Here we report that a gene (formerlyyukFand now designatedadeR) located upstream ofaldis essential for the basal and alanine-inducible expression ofald. The disruption of theadeRgene caused a sporulation defect, whereas the complementation of anadeRmutation with an intactadeRgene restored the sporulation ability.adeRexpression was not subject to autoregulation and alanine induction. Deletion and mutation analyses revealed that an inverted repeat, centered at position −74.5 relative to the transcriptional initiation site ofald, was required foraldexpression and also likely served as a ρ-independent transcription terminator. Electrophoretic mobility shift assays showed that purified His-tagged AdeR was a specific DNA-binding protein and that this inverted repeat was required for AdeR binding. AdeR shows no significant amino acid sequence similarity to the known transcriptional activators ofaldgenes from other bacteria. AdeR appears to be a member of the PucR family of transcriptional regulators. Its orthologs of unknown function are present in some otherBacillusspecies. Collectively, these findings support the notion that AdeR is a transcriptional activator which mediatesaldexpression in response to alanine availability and is important for normal sporulation inB. subtilis.

scholarly journals SpCoel1: a sea urchin profilin gene expressed specifically in coelomocytes in response to injury.

1992 ◽  
Vol 3 (4) ◽  
pp. 403-414 ◽  
Author(s):  
L C Smith ◽  
R J Britten ◽  
E H Davidson
Keyword(s):  
Sea Urchin ◽  
Sequence Similarity ◽  
Single Copy ◽  
Untranslated Regions ◽  
Amino Acid Sequence Similarity ◽  
Signal Transduction System ◽  
Reading Frame ◽  
Purple Sea Urchin ◽  
Copy Gene ◽  
External Injury

SpCoel1 is a single copy gene that is specifically expressed in most of the coelomocytes of the adult purple sea urchin, Strongylocentrotus purpuratus. The 4-kb transcript from this gene has a relatively short (426 nucleotide) open reading frame (ORF) with long 3' and 5' untranslated regions. The ORF encodes a protein that has strong amino acid sequence similarity to profilins from yeast to mammals. Transcript titrations of SpCoel1 show significant increases per coelomocyte in animals that have been physiologically challenged. Increases in transcript levels are of similar magnitudes between animals receiving different treatments, such as injuries from needle punctures or from injections of foreign cells. The evidence presented here implies a molecular mechanism by which this lower deuterostome defense system responds to external insult, viz that an external "injury signal" activates a signal transduction system, which in turn mediates the alterations in cytoskeletal state that are required for coelomocyte activation.

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