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‣ Report of a chimeric origin of transposable elements in a bovine-coding gene

Almeida, L. M.; Amaral, M. E J; Silva, I. T.; Silva, W. A.; Riggs, P. K.; Carareto, C. M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 107-116
Português
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Despite the wide distribution of transposable elements (TEs) in mammalian genomes, part of their evolutionary significance remains to be discovered. Today there is a substantial amount of evidence showing that TEs are involved in the generation of new exons in different species. In the present study, we searched 22,805 genes and reported the occurrence of TE-cassettes in coding sequences of 542 cow genes using the RepeatMasker program. Despite the significant number (542) of genes with TE insertions in exons only 14 (2.6%) of them were translated into protein, which we characterized as chimeric genes. From these chimeric genes, only the FAST kinase domains 3 (FASTKD3) gene, present on chromosome BTA 20, is a functional gene and showed evidence of the exaptation event. The genome sequence analysis showed that the last exon coding sequence of bovine FASTKD3 is ∼85% similar to the ART2A retrotransposon sequence. In addition, comparison among FASTKD3 proteins shows that the last exon is very divergent from those of Homo sapiens, Pan troglodytes and Canis familiares. We suggest that the gene structure of bovine FASTKD3 gene could have originated by several ectopic recombinations between TE copies. Additionally, the absence of TE sequences in all other species analyzed suggests that the TE insertion is clade-specific...

‣ Análise molecular parcial dos genes VP1 e VP2 do vírus da doença infecciosa da bursa isolados no Brasil; Analysis on partial sequence of VP1 and VP2 genes of the Brazilian infectious bursal disease virus isolated in Brazil

Maria Judite Bittencourt Fernandes
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/05/2010 Português
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A doença infecciosa da bursa (IBD), denominada também doença de Gumboro, é uma doença aguda, imunossupressora, altamente contagiosa de aves jovens e de grande importância econômica para a avicultura. O vírus da doença infecciosa da bursa (IBDV), sorotipo 1, pode ser classificado de acordo com sua antigenicidade e patogenicidade em amostras clássicas virulentas (cv), atenuadas, variantes antigênicas ou muito virulentas (vv). Estas diferenças antigênicas são encontradas na região hipervariável do gene VP2, que é responsável pela indução de anticorpos neutralizantes e também dos possíveis marcadores de virulência que ainda não estão bem estabelecidos. O gene VP1 parece também apresentar um papel na virulência do vírus. Primeiramente, o objetivo do presente trabalho foi a identificação e caracterização molecular de 66 amostras brasileiras de IBDV através da RT-PCR de um fragmento do gene VP2 seguida pela digestão por enzimas de restrição (RE) e posterior confirmação pelo sequenciamento. A análise da RT-PCR/RE classificou 25 isolados como cepas vv e 16 como cepas cv além da classificação de 6 grupo moleculares. O sequenciamento também confirmou esta classificação com a presnça dos aminoácidos (aa) típicos das amostras vv (222A...

‣ Lactarius deliciosus isolate UEZB1 internal transcribed spacer 1, partial sequence; 5.8S ribosomal RNA gene and internal transcribed spacer 2, complete sequence; and 28S ribosomal RNA gene, partial sequence

Santos-Silva, Celeste; Louro, Rogério; Ragonezi, Carla; Caldeira, Ana Teresa; Martins, Maria Rosário; Klimaszewska, Kristina; Ganhão, Elsa; Zavattieri, Amely
Fonte: National Center for Biotechnology Information, GENBANK, USA Publicador: National Center for Biotechnology Information, GENBANK, USA
Tipo: Aula
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LOCUS JQ066791 439 bp DNA linear PLN 20-MAR-2012 DEFINITION Lactarius deliciosus isolate UEZB1 internal transcribed spacer 1, partial sequence; 5.8S ribosomal RNA gene and internal transcribed spacer 2, complete sequence; and 28S ribosomal RNA gene, partial sequence. ACCESSION JQ066791 VERSION JQ066791.1 GI:380467948 KEYWORDS . SOURCE Lactarius deliciosus ORGANISM Lactarius deliciosus Eukaryota; Fungi; Dikarya; Basidiomycota; Agaricomycotina; Agaricomycetes; Russulales; Russulaceae; Lactarius.

‣ Cloning and characterization of SmZF1, a gene encoding a Schistosoma mansoni zinc finger protein

Souza,Paulo R Eleutério de; Valadão,Analina F; Calzavara-Silva,Carlos E; Franco,Glória R; Morais Júnior,Marcos A de; Abath,Frederico GC
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2001 Português
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The zinc finger motifs (Cys2His2) are found in several proteins playing a role in the regulation of transcripton. SmZF1, a Schistosoma mansoni gene encoding a zinc finger protein was initially isolated from an adult worm cDNA library, as a partial cDNA. The full sequence of the gene was obtained by subcloning and sequencing cDNA and genomic fragments. The collated gene sequence is 2181 nt and the complete cDNA sequence is 705 bp containing the full open reading frame of the gene. Analysis of the genome sequence revealed the presence of three introns interrupting the coding region. The open reading frame theoretically encodes a protein of 164 amino acids, with a calculated molecular mass of 18,667Da. The predicted protein contains three zinc finger motifs, usually present in transcription regulatory proteins. PCR amplification with specific primers for the gene allowed for the detection of the target in egg, cercariae, schistosomulum and adult worm cDNA libraries indicating the expression of the mRNA in these life cycle stages of S. mansoni. This pattern of expression suggests the gene plays a role in vital functions of different life cycle stages of the parasite. Future research will be directed to elucidate the functional role of SmZF1.

‣ Identification and characterization of rhizospheric microbial diversity by 16S ribosomal RNA gene sequencing

Naveed,Muhammad; Mubeen,Samavia; khan,SamiUllah; Ahmed,Iftikhar; Khalid,Nauman; Suleria,Hafiz Ansar Rasul; Bano,Asghari; Mumtaz,Abdul Samad
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 Português
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In the present study, samples of rhizosphere and root nodules were collected from different areas of Pakistan to isolate plant growth promoting rhizobacteria. Identification of bacterial isolates was made by 16S rRNA gene sequence analysis and taxonomical confirmation on EzTaxon Server. The identified bacterial strains were belonged to 5 genera i.e. Ensifer, Bacillus, Pseudomona, Leclercia and Rhizobium. Phylogenetic analysis inferred from 16S rRNA gene sequences showed the evolutionary relationship of bacterial strains with the respective genera. Based on phylogenetic analysis, some candidate novel species were also identified. The bacterial strains were also characterized for morphological, physiological, biochemical tests and glucose dehydrogenase (gdh) gene that involved in the phosphate solublization using cofactor pyrroloquinolone quinone (PQQ). Seven rhizoshperic and 3 root nodulating stains are positive for gdh gene. Furthermore, this study confirms a novel association between microbes and their hosts like field grown crops, leguminous and non-leguminous plants. It was concluded that a diverse group of bacterial population exist in the rhizosphere and root nodules that might be useful in evaluating the mechanisms behind plant microbial interactions and strains QAU-63 and QAU-68 have sequence similarity of 97 and 95% which might be declared as novel after further taxonomic characterization.

‣ Gene sequence tags from Plasmodium falciparum genomic DNA fragments prepared by the "genease" activity of mung bean nuclease.

Reddy, G R; Chakrabarti, D; Schuster, S M; Ferl, R J; Almira, E C; Dame, J B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/11/1993 Português
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A genes-first approach to genome sequencing is described which efficiently generates gene sequence tags from genomic DNA. Mung bean nuclease (EC 3.1.30.1) cleaves the genomic DNA of many organisms before and after genes and within some introns. Analysis of gene sequence tags prepared from mung bean nuclease-digested Plasmodium falciparum DNA demonstrates that this method has several advantages over the popular cDNA expressed sequence tag approach. To date, 673 sequence tags containing over 215 kb of sequence have been generated from 400 clones. Sixty clones (15%) have significant similarity to sequences in the protein and translated nucleic acid data bases. These represent 51 unique genes, of which only 5 encode previously known P. falciparum proteins. The identified proteins include those expressed in erythrocytic, exoerythrocytic, and gametocytic stages of the parasite. Thirty percent of clones identified appear to carry complete coding regions. The spacer DNA separating genes is rarely cloned. These gene sequence tags will form a useful data base from which to initiate projects to develop new therapeutics, vaccines, and strategies to control human malaria.

‣ Plants transformed with a tobacco mosaic virus nonstructural gene sequence are resistant to the virus.

Golemboski, D B; Lomonossoff, G P; Zaitlin, M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1990 Português
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Nicotiana tabacum cv. Xanthi nn plants were transformed with nucleotides 3472-4916 of tobacco mosaic virus (TMV) strain U1. This sequence contains all but the three 3 terminal nucleotides of the TMV 54-kDa gene, which encodes a putative component of the replicase complex. These plants were resistant to infection when challenged with either TMV U1 virions or TMV U1 RNA at concentrations of up to 500 micrograms/ml or 300 micrograms/ml, respectively, the highest concentrations tested. Resistance was also exhibited when plants were inoculated at 100 micrograms/ml with the closely related TMV mutant YSI/1 but was not shown in plants challenged at the same concentrations with the more distantly related TMV strains U2 or L or cucumber mosaic virus. Although the copy number of the 54-kDa gene sequence varied in individual transformants from 1 to approximately 5, the level of resistance in plants was not dependent on the number of copies of the 54-kDa gene sequence integrated. The transformed plants accumulated a 54-kDa gene sequence-specific RNA transcript of the expected size, but no protein product was detected.

‣ Impact of 16S rRNA Gene Sequence Analysis for Identification of Bacteria on Clinical Microbiology and Infectious Diseases

Clarridge, Jill E.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/2004 Português
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The traditional identification of bacteria on the basis of phenotypic characteristics is generally not as accurate as identification based on genotypic methods. Comparison of the bacterial 16S rRNA gene sequence has emerged as a preferred genetic technique. 16S rRNA gene sequence analysis can better identify poorly described, rarely isolated, or phenotypically aberrant strains, can be routinely used for identification of mycobacteria, and can lead to the recognition of novel pathogens and noncultured bacteria. Problems remain in that the sequences in some databases are not accurate, there is no consensus quantitative definition of genus or species based on 16S rRNA gene sequence data, the proliferation of species names based on minimal genetic and phenotypic differences raises communication difficulties, and microheterogeneity in 16S rRNA gene sequence within a species is common. Despite its accuracy, 16S rRNA gene sequence analysis lacks widespread use beyond the large and reference laboratories because of technical and cost considerations. Thus, a future challenge is to translate information from 16S rRNA gene sequencing into convenient biochemical testing schemes, making the accuracy of the genotypic identification available to the smaller and routine clinical microbiology laboratories.

‣ Phylogeny and Identification of Enterococci by atpA Gene Sequence Analysis

Naser, S.; Thompson, F. L.; Hoste, B.; Gevers, D.; Vandemeulebroecke, K.; Cleenwerck, I.; Thompson, C. C.; Vancanneyt, M.; Swings, J.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2005 Português
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The relatedness among 91 Enterococcus strains representing all validly described species was investigated by comparing a 1,102-bp fragment of atpA, the gene encoding the alpha subunit of ATP synthase. The relationships observed were in agreement with the phylogeny inferred from 16S rRNA gene sequence analysis. However, atpA gene sequences were much more discriminatory than 16S rRNA for species differentiation. All species were differentiated on the basis of atpA sequences with, at a maximum, 92% similarity. Six members of the Enterococcus faecium species group (E. faecium, E. hirae, E. durans, E. villorum, E. mundtii, and E. ratti) showed >99% 16S rRNA gene sequence similarity, but the highest value of atpA gene sequence similarity was only 89.9%. The intraspecies atpA sequence similarities for all species except E. faecium strains varied from 98.6 to 100%; the E. faecium strains had a lower atpA sequence similarity of 96.3%. Our data clearly show that atpA provides an alternative tool for the phylogenetic study and identification of enterococci.

‣ secA1 Gene Sequence Polymorphisms for Species Identification of Nocardia Species and Recognition of Intraspecies Genetic Diversity▿ †

Kong, Fanrong; Wang, Huiping; Zhang, Erqing; Sintchenko, Vitali; Xiao, Meng; Sorrell, Tania C.; Chen, Xiaoyou; Chen, Sharon C.-A.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
Português
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Sequence analysis of the Nocardia essential secretory protein SecA1 gene (secA1) for species identification of 120 American Type Culture Collection (ATCC) and clinical isolates of Nocardia (16 species) was studied in comparison with 5′-end 606-bp 16S rRNA gene sequencing. Species determination by both methods was concordant for all 10 ATCC strains. secA1 gene sequencing provided the same species identification as 16S rRNA gene analysis for 94/110 (85.5%) clinical isolates. However, 40 (42.6%) isolates had sequences with <99.0% similarity to archived secA1 sequences for the species, including 29 Nocardia cyriacigeorgica (96.6 to 98.9% similarity) and 4 Nocardia veterana (91.5 to 98.9% similarity) strains. Discrepant species identification was obtained for 16 (14.5%) clinical isolates, including 13/23 Nocardia nova strains (identified as various Nocardia species by secA1 sequencing) and 1 isolate each of Nocardia abscessus (identified as Nocardia asiatica), Nocardia elegans (Nocardia africana), and Nocardia transvalensis (Nocardia blacklockiae); both secA1 gene sequence analysis and deduced amino acid sequence analysis determined the species to be different from those assigned by 16S rRNA gene sequencing. The secA1 locus showed high sequence diversity (66 sequence or genetic types versus 40 16S rRNA gene sequence types)...

‣ Ancient Properties of Spider Silks Revealed by the Complete Gene Sequence of the Prey-Wrapping Silk Protein (AcSp1)

Ayoub, Nadia A.; Garb, Jessica E.; Kuelbs, Amanda; Hayashi, Cheryl Y.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
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Spider silk fibers have impressive mechanical properties and are primarily composed of highly repetitive structural proteins (termed spidroins) encoded by a single gene family. Most characterized spidroin genes are incompletely known because of their extreme size (typically >9 kb) and repetitiveness, limiting understanding of the evolutionary processes that gave rise to their unusual gene architectures. The only complete spidroin genes characterized thus far form the dragline in the Western black widow, Latrodectus hesperus. Here, we describe the first complete gene sequence encoding the aciniform spidroin AcSp1, the primary component of spider prey-wrapping fibers. L. hesperus AcSp1 contains a single enormous (∼19 kb) exon. The AcSp1 repeat sequence is exceptionally conserved between two widow species (∼94% identity) and between widows and distantly related orb-weavers (∼30% identity), consistent with a history of strong purifying selection on its amino acid sequence. Furthermore, the 16 repeats (each 371–375 amino acids long) found in black widow AcSp1 are, on average, >99% identical at the nucleotide level. A combination of stabilizing selection on amino acid sequence, selection on silent sites, and intragenic recombination likely explains the extreme homogenization of AcSp1 repeats. In addition...

‣ Deletion of the UL4 gene sequence of equine herpesvirus 1 precludes the generation of defective interfering particles

Charvat, Robert A.; Zhang, Yunfei; O’Callaghan, Dennis J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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Serial, high multiplicity passage of equine herpesvirus 1 (EHV-1) leads to the generation of defective interfering particles (DIP). EHV-1 DIP inhibit and interfere with the replication of standard EHV-1, establishing a state of persistent infection. These DIP package severely truncated and rearranged forms of the standard viral genome. Contained within the DIP genome are only three genes: UL3, UL4, and a unique hybrid gene (Hyb). The hybrid gene forms through a recombination event that fuses portions of the early regulatory IR4 and UL5 genes and is essential for DIP-mediated interference. The UL4 gene is an early gene dispensable for lytic replication and inhibits viral and cellular gene expression. However, the contribution of the UL4 gene during DIP-mediated persistent infection is unknown. Here, we describe the generation of a completely deleted UL4 virus and its use to investigate the role of the UL4 gene in the generation of the defective genome. Deletion of the UL4 gene resulted in delayed virus growth at late times post-infection. Cells infected with a mutant EHV-1 that lacked expression of the UL4 protein due to an inserted stop codon in the UL4 gene produced defective particles, while cells infected with a mutant EHV-1 that had the complete UL4 gene sequence deleted were unable to produce DIP. These data suggest that the UL4 gene sequence...

‣ The Unique hmuY Gene Sequence as a Specific Marker of Porphyromonas gingivalis

Gmiterek, Anna; Wójtowicz, Halina; Mackiewicz, Paweł; Radwan-Oczko, Małgorzata; Kantorowicz, Małgorzata; Chomyszyn-Gajewska, Maria; Frąszczak, Magdalena; Bielecki, Marcin; Olczak, Mariusz; Olczak, Teresa
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 02/07/2013 Português
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Porphyromonas gingivalis, a major etiological agent of chronic periodontitis, acquires heme from host hemoproteins using the HmuY hemophore. The aim of this study was to develop a specific P. gingivalis marker based on a hmuY gene sequence. Subgingival samples were collected from 66 patients with chronic periodontitis and 40 healthy subjects and the entire hmuY gene was analyzed in positive samples. Phylogenetic analyses demonstrated that both the amino acid sequence of the HmuY protein and the nucleotide sequence of the hmuY gene are unique among P. gingivalis strains/isolates and show low identity to sequences found in other species (below 50 and 56%, respectively). In agreement with these findings, a set of hmuY gene-based primers and standard/real-time PCR with SYBR Green chemistry allowed us to specifically detect P. gingivalis in patients with chronic periodontitis (77.3%) and healthy subjects (20%), the latter possessing lower number of P. gingivalis cells and total bacterial cells. Isolates from healthy subjects possess the hmuY gene-based nucleotide sequence pattern occurring in W83/W50/A7436 (n = 4), 381/ATCC 33277 (n = 3) or TDC60 (n = 1) strains, whereas those from patients typically have TDC60 (n = 21)...

‣ Sequence analysis of the mip gene of the soilborne pathogen Legionella longbeachae.

Doyle, R.; Steele, T.; McLennan, A.; Parkinson, I.; Manning, P.; Heuzenroeder, M.
Fonte: AMER SOC MICROBIOLOGY Publicador: AMER SOC MICROBIOLOGY
Tipo: Artigo de Revista Científica
Publicado em //1998 Português
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To understand the basis of pathogenesis by Legionella longbeachae serogroup 1, the importance of the Mip protein in this species was examined. Amino-terminal analysis of the purified, cloned L. longbeachae serogroup 1 ATCC 33462 Mip protein confirmed that the cloned gene protein was expressed and processed in an Escherichia coli background. DNA sequence analysis of plasmid pIMVS27, containing the entire L. longbeachae serogroup 1 mip gene, revealed a high degree of homology to the mip gene of Legionella pneumophila serogroup 1, 76% homology at the DNA level and 87% identity at the amino acid level. Primer extension analysis determined that the start site of transcription was the same for both species, with some differences observed for the 10 and 35 promoter regions. Primers designed from the mip gene sequence obtained for L. longbeachae serogroup 1 ATCC 33462 were used to amplify the mip genes from L. longbeachae serogroup 2 ATCC 33484 and an Australian clinical isolate of L. longbeachae serogroup 1 A5H5. The mip gene from A5H5 was 100% identical to the type strain sequence. The serogroup 2 strain of L. longbeachae differed by 2 base pairs in third-codon positions. Allelic exchange mutagenesis was used to generate an isogenic mip mutant in ATCC 33462 and strain A5H5. The ATCC mip mutant was unable to infect a strain of Acanthamoebae sp. both in liquid and in a potting mix coculture system...

‣ Detection of Fusobacterium necrophorum leukotoxin (lkta) gene sequence in the oral cavity of captive macropods

Antiabong, J.; Boardman, W.; Smith, I.; Brown, M.; Ball, A.; Goodman, A.
Fonte: SciTechnol Publicador: SciTechnol
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
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Fusobacterium necrophorum is an important aetiological agent of periodontal diseases (gingivitis and lumpy jaw) in captive macropods. The leukotoxin encoded by the lktA gene is a major virulence factor of F. necrophorum. In the present study, lktA gene sequences were detected by PCR in the oral cavity of 21/58 (36%) captive yellow footed rock wallabies and mainland tammar wallabies at two zoological parks in South Australia. This suggest that F. necrophorum encoded lktA may not be present in the oral cavity of all captive wallabies or that it is present at low levels, i.e. close to the limits of detection of conventional PCR. The lktA sequences had 98-100% homology to a sequence detected in ovine foot lesions infected with F. necrophorum. Cluster analysis of the partial lktA gene sequence revealed two clades of the lktA gene of F. necrophorum in macropods and calls for a detailed study using the whole gene sequence.; John F Antiabong, Wayne Boardman, Ian Smith, Melissa H Brown, Andrew S Ball and Amanda E Goodman

‣ The 5.8S RNA gene sequence and the ribosomal repeat of Schizosaccharomyces pombe.

Schaak, J; Mao, J; Söll, D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 11/05/1982 Português
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We have characterized the rRNA gene repeat in Schizosaccharomyces pombe. This repeat, which does not contain the 5S RNA gene, is found in a 10.4 kb HindIII DNA fragment. We have determined the nucleotide sequences of the S. pombe 5.8S RNA gene and intergenic spacers from two different 10.4 kb DNA fragments. Analysis of isolated total cellular 5.8S RNA revealed the presence of eight species of 5.8S RNA, differing in the number of nucleotides at the 5'-end. The eight 4.8S RNA species vary in length from 158 to 165 nucleotides. Apart from the heterogeneity observed at the 5'-end, the sequence of the eight 5.8S RNA species appears to be identical and is the same sequence as coded for by the 5.8S genes. The gene sequence shows great homology to the 5.8S RNA genes or S. cerevisiae and N. crassa. Most of the base differences are confined to the highly variable stem though to be involved in co-axial helix stacking with the 25S RNA, where base pairing is nearly identical despite the sequence differences. Secondary structure models are examined in light of 5.8S RNA oligonucleotide conservation across species from yeasts to higher eukaryotes.

‣ The nucleotide sequence of the mouse immunoglobulin epsilon gene: comparison with the human epsilon gene sequence.

Ishida, N; Ueda, S; Hayashida, H; Miyata, T; Honjo, T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1982 Português
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We have determined the nucleotide sequence of the immunoglobulin epsilon gene cloned from newborn mouse DNA. The epsilon gene sequence allows prediction of the amino acid sequence of the constant region of the epsilon chain and comparison of it with sequences of the human epsilon and other mouse immunoglobulin genes. The epsilon gene was shown to be under the weakest selection pressure at the protein level among the immunoglobulin genes although the divergence at the synonymous position is similar. Our results suggest that the epsilon gene may be dispensable, which is in accord with the fact that IgE has only obscure roles in the immune defense system but has an undesirable role as a mediator of hypersensitivity. The sequence data suggest that the human and murine epsilon genes were derived from different ancestors duplicated a long time ago. The amino acid sequence of the epsilon chain is more homologous to those of the gamma chains than the other mouse heavy chains. Two membrane exons, separated by an 80-base intron, were identified 1.7 kb 3' to the CH4 domain of the epsilon gene and shown to conserve a hydrophobic portion similar to those of other heavy chain genes. RNA blot hybridization showed that the epsilon membrane exons are transcribed into two species of mRNA in an IgE hybridoma.

‣ Coat protein gene sequence of tobacco mosaic virus encodes a host response determinant.

Saito, T; Meshi, T; Takamatsu, N; Okada, Y
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1987 Português
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The common strain and tomato strain of tobacco mosaic virus (TMV) are known to be closely related to each other. However, plants with the N' gene, such as Nicotiana sylvestris and Nicotiana tabacum L. cv. Bright Yellow, respond differently to infections by these viruses. In the N' plants, TMV-OM (common strain) spreads systemically with mosaic symptoms, whereas TMV-L (tomato strain) induces the necrotic response of plants, causing local lesions. To reveal the viral factor of TMV-L inducing the necrotic response, we have constructed several recombinant viruses between the two strains, in which TMV-L RNA was partly replaced by TMV-OM RNA. The recombinant viruses having the coat protein gene sequence of TMV-OM in place of TMV-L produced no necrotic local lesions but spread systemically with mosaic symptoms in the N' plants. On the other hand, the recombinant viruses having TMV-OM-derived sequences other than the coat protein gene sequence, and in which the coat protein gene sequence of TMV-L still remained, produced necrotic local lesions. These observations indicate that the viral factor of TMV-L responsible for the necrotic response of the N' plants is coded in the coat protein gene sequence.

‣ Contribution of the Caspase Gene Sequence Diversification to the Specifically Antiviral Defense in Invertebrate

Zhi, Bin; Wang, Lei; Wang, Guangyi; Zhang, Xiaobo
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/09/2011 Português
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Vertebrates achieve adaptive immunity of all sorts against pathogens through the diversification of antibodies. However the mechanism of invertebrates' innate immune defense against various pathogens remains largely unknown. Our study used shrimp and white spot syndrome virus (WSSV) to show that PjCaspase, a caspase gene of shrimp that is crucial in apoptosis, possessed gene sequence diversity. At present, the role of gene sequence diversity in immunity has not been characterized. To address this issue, we compared the PjCaspase gene sequence diversities from WSSV-free and WSSV-resistant shrimp. The sequence analysis indicated that the PjCaspase gene from the WSSV-resistant shrimp contained a special fragment, designated as fragment 3 (221–229 aa). Down-regulation or overexpression of the PjCaspase gene containing fragment 3 led to significant inhibition or enhancement of virus-induced apoptosis, but had no effect on bacterium challenge. We found evidence that the silencing or overexpression of this gene led to a 7-fold increase or 11-fold decrease of WSSV copies, respectively. Our results suggested that the PjCaspase gene containing fragment 3 provided the molecular basis for the antiviral defense of shrimp. This study represented the first report of the role of gene sequence diversity in the immunity of an invertebrate against virus infection. Invertebrates may employ this gene sequence diversity as a system to avoid pathogen interference with their immune response.

‣ Study of promoter and structural gene sequence of whiB7 in MDR and XDR forms of Mycobacterium tuberculosis

Arjomandzadegan,M; Sadrnia,M; Surkova,LK; Titov,LP
Fonte: West Indian Medical Journal Publicador: West Indian Medical Journal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 Português
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Resistance phenomenon in M tuberculosis is mainly based on decreased permeability of the bacterial envelope and function of effluent pumps. The regulatory gene of the whiB7 transcription determines drug resistance in these bacteria. Increases in WhiB7 protein activity induce transcription of resistance genes leading to intrinsic multidrug resistance. The aim of this work was to evaluate the whiB7 gene sequence in susceptible, MDR and XDR clinical isolates of M tuberculosis in order to further design an inhibitor. Thirty-three clinical isolates of MTB identified as susceptible, MDR and XDR-TB were investigated by PCRfor sequencing of the entire promoter (429 bp), structural gene (279 bp) and the end of the upstream gene uvrD (265 bp). No differences were detected in the sequences of the structural gene in susceptible and MDR with XDR isolates and all of them terminated at TGA as stop codon. Examination of sequence profiles of the promoter part of whiB7 by several sets ofprimers proved that there were no differences between sequence ofsusceptible, MDR and XDR isolates by type strain (H37Rr). Furthermore, the structure of WhiB7 protein was studied in achieved sequences from clinical isolates. We found that the promoter and structural gene of whiB7 are highly conservative in clinical susceptible and resistant isolates. It is a key finding that would assist in the design ofan inhibitor for the WhiB7 protein in all clinical forms in further studies.