Intron mobility in the T-even phages: High frequency inheritance of group I introns promoted by intron open reading frames

Cell ◽  
1989 ◽  
Vol 56 (3) ◽  
pp. 455-465 ◽  
Author(s):  
Susan M. Quirk ◽  
Deborah Bell-Pedersen ◽  
Marlene Belfort
Keyword(s):  
High Frequency ◽  
Open Reading Frames ◽  
Group I Introns ◽  
Group I ◽  
Intron Mobility ◽  
Reading Frames

scholarly journals Two group I introns with long internal open reading frames in the chloroplastpsbAgene ofChlamydomonas moewusii

1989 ◽  
Vol 17 (10) ◽  
pp. 3875-3887 ◽  
Author(s):  
Monique Turmel ◽  
Jean Boulanger ◽  
Claude Lemieux
Keyword(s):  
Open Reading Frames ◽  
Group I Introns ◽  
Group I ◽  
Reading Frames

scholarly journals Two Phages, phiIPLA-RODI and phiIPLA-C1C, Lyse Mono- and Dual-Species Staphylococcal Biofilms

2015 ◽  
Vol 81 (10) ◽  
pp. 3336-3348 ◽  
Author(s):  
Diana Gutiérrez ◽  
Dieter Vandenheuvel ◽  
Beatriz Martínez ◽  
Ana Rodríguez ◽  
Rob Lavigne ◽  
...  
Keyword(s):  
Phage Therapy ◽  
Gene Organization ◽  
Open Reading Frames ◽  
Group I Introns ◽  
High Similarity ◽  
Content Type ◽  
Staphylococcal Infections ◽  
Group I ◽  
Genes Encoding ◽  
Reading Frames

ABSTRACTPhage therapy is a promising option for fighting against staphylococcal infections. Two lytic phages, vB_SauM_phiIPLA-RODI (phiIPLA-RODI) and vB_SepM_phiIPLA-C1C (phiIPLA-C1C), belonging to theMyoviridaefamily and exhibiting wide host ranges, were characterized in this study. The complete genome sequences comprised 142,348 bp and 140,961 bp and contained 213 and 203 open reading frames, respectively. The gene organization was typical ofSpounavirinaemembers, with long direct terminal repeats (LTRs), genes grouped into modules not clearly separated from each other, and several group I introns. In addition, four genes encoding tRNAs were identified in phiIPLA-RODI. Comparative DNA sequence analysis showed high similarities with two phages, GH15 and 676Z, belonging to theTwort-like virusgenus (nucleotide identities of >84%); for phiIPLA-C1C, a high similarity with phage phiIBB-SEP1 was observed (identity of 80%). Challenge assays of phages phiIPLA-RODI and phiIPLA-C1C against planktonic staphylococcal cells confirmed their lytic ability, as they were able to remove 5 log units in 8 h. Exposure of biofilms to phages phiIPLA-RODI and phiIPLA-C1C reduced the amount of adhered bacteria to about 2 log units in both monospecies and dual-species biofilms, but phiIPLA-RODI turned out to be as effective as the mixture of both phages. Moreover, the frequencies of bacteriophage-insensitive mutants (BIMs) ofStaphylococcus aureusandS. epidermidiswith resistance to phiIPLA-RODI and phiIPLA-C1C were low, at 4.05 × 10−7± 2.34 × 10−9and 1.1 × 10−7± 2.08 × 10−9, respectively. Overall, a generally reduced fitness in the absence of phages was observed for BIMs, which showed a restored phage-sensitive phenotype in a few generations. These results confirm that lytic bacteriophages can be efficient biofilm-disrupting agents, supporting their potential as antimicrobials against staphylococcal infections.

scholarly journals Nucleolar introns fromPhysarum flavicomumcontain insertion elements that may explain how mobile group I introns gained their open reading frames

1994 ◽  
Vol 22 (22) ◽  
pp. 4553-4559 ◽  
Author(s):  
Anna Vader ◽  
Jørund Naess ◽  
Kari Haugli ◽  
Finn Haugli ◽  
Steinar Johansen
Keyword(s):  
Open Reading Frames ◽  
Group I Introns ◽  
Group I ◽  
Insertion Elements ◽  
Reading Frames

scholarly journals Mitochondrial Intronic Open Reading Frames in Podospora: Mobility and Consecutive Exonic Sequence Variations

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 777-788 ◽  
Author(s):  
Carole H Sellem ◽  
Yves d'Aubenton-Carafa ◽  
Michèle Rossignol ◽  
Léon Belcour
Keyword(s):  
Mitochondrial Genome ◽  
Open Reading Frames ◽  
Nucleotide Substitutions ◽  
Sequence Comparisons ◽  
Modular Evolution ◽  
Group I ◽  
Sequence Variations ◽  
Type Strains ◽  
Reading Frames ◽  
Adjacent Exon

Abstract The mitochondrial genome of 23 wild-type strains belonging to three different species of The mitochondrial genome the filamentous fungus Podospora was examined. Among the 15 optional sequences identified are two intronic reading frames, nad1-i4-orf1 and cox1-i7-orf2. We show that the presence of these sequences was strictly correlated with tightly clustered nucleotide substitutions in the adjacent exon. This correlation applies to the presence or absence of closely related open reading frames (ORFs), found at the same genetic locations, in all the Pyrenomycete genera examined. The recent gain of these optional ORFs in the evolution of the genus Podospora probably account for such sequence differences. In the homoplasmic progeny from heteroplasmons constructed between Podospora strains differing by the presence of these optional ORFs, nad1-i4-orf1 and cox1-i7-orf2 appeared highly invasive. Sequence comparisons in the nad1-i4 intron of various strains of the Pyrenomycete family led us to propose a scenario of its evolution that includes several events of loss and gain of intronic ORFs. These results strongly reinforce the idea that group I intronic ORFs are mobile elements and that their transfer, and comcomitant modification of the adjacent exon, could participate in the modular evolution of mitochondrial genomes.

scholarly journals Mobile Self-Splicing Group I Introns from thepsbA Gene of Chlamydomonas reinhardtii: Highly Efficient Homing of an Exogenous Intron Containing Its Own Promoter

2001 ◽  
Vol 21 (10) ◽  
pp. 3472-3481 ◽  
Author(s):  
Obed W. Odom ◽  
Stephen P. Holloway ◽  
Nita N. Deshpande ◽  
Jaesung Lee ◽  
David L. Herrin
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Open Reading Frames ◽  
Group I Introns ◽  
Resistance Marker ◽  
Free Standing ◽  
Spectinomycin Resistance ◽  
Highly Efficient ◽  
Group I ◽  
Short Exon ◽  
Self Splicing

ABSTRACT Introns 2 and 4 of the psbA gene of Chlamydomonas reinhardtii chloroplasts (Cr.psbA2 andCr.psbA4, respectively) contain large free-standing open reading frames (ORFs). We used transformation of an intronless-psbA strain (IL) to test whether these introns undergo homing. Each intron, plus short exon sequences, was cloned into a chloroplast expression vector in both orientations and then cotransformed into IL along with a spectinomycin resistance marker (16Srrn). For Cr.psbA2, the sense construct gave nearly 100% cointegration of the intron whereas the antisense construct gave 0%, consistent with homing. For Cr.psbA4, however, both orientations produced highly efficient cointegration of the intron. Efficient cointegration of Cr.psbA4 also occurred when the intron was introduced as a restriction fragment lacking any known promoter. Deletion of most of the ORF, however, abolished cointegration of the intron, consistent with homing. TheCr.psbA4 constructs also contained a 3-(3,4-dichlorophenyl)-1,1-dimethylurea resistance marker in exon 5, which was always present when the intron integrated, thus demonstrating exon coconversion. Remarkably, primary selection for this marker gave >100-fold more transformants (>10,000/μg of DNA) than did the spectinomycin resistance marker. A trans homing assay was developed for Cr.psbA4; the ORF-minus intron integrated when the ORF was cotransformed on a separate plasmid. This assay was used to identify an intronic region between bp −88 and −194 (relative to the ORF) that stimulated homing and contained a possible bacterial (−10, −35)-type promoter. Primer extension analysis detected a transcript that could originate from this promoter. Thus, this mobile, self-splicing intron also contains its own promoter for ORF expression. The implications of these results for horizontal intron transfer and organelle transformation are discussed.

scholarly journals Complete Genome Sequence of the Broad-Host-Range Vibriophage KVP40: Comparative Genomics of a T4-Related Bacteriophage

2003 ◽  
Vol 185 (17) ◽  
pp. 5220-5233 ◽  
Author(s):  
Eric S. Miller ◽  
John F. Heidelberg ◽  
Jonathan A. Eisen ◽  
William C. Nelson ◽  
A. Scott Durkin ◽  
...  
Keyword(s):  
Host Range ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Gene Clusters ◽  
Open Reading Frames ◽  
Broad Host Range ◽  
Group I Introns ◽  
Repair Enzymes ◽  
Group I

ABSTRACT The complete genome sequence of the T4-like, broad-host-range vibriophage KVP40 has been determined. The genome sequence is 244,835 bp, with an overall G+C content of 42.6%. It encodes 386 putative protein-encoding open reading frames (CDSs), 30 tRNAs, 33 T4-like late promoters, and 57 potential rho-independent terminators. Overall, 92.1% of the KVP40 genome is coding, with an average CDS size of 587 bp. While 65% of the CDSs were unique to KVP40 and had no known function, the genome sequence and organization show specific regions of extensive conservation with phage T4. At least 99 KVP40 CDSs have homologs in the T4 genome (Blast alignments of 45 to 68% amino acid similarity). The shared CDSs represent 36% of all T4 CDSs but only 26% of those from KVP40. There is extensive representation of the DNA replication, recombination, and repair enzymes as well as the viral capsid and tail structural genes. KVP40 lacks several T4 enzymes involved in host DNA degradation, appears not to synthesize the modified cytosine (hydroxymethyl glucose) present in T-even phages, and lacks group I introns. KVP40 likely utilizes the T4-type sigma-55 late transcription apparatus, but features of early- or middle-mode transcription were not identified. There are 26 CDSs that have no viral homolog, and many did not necessarily originate from Vibrio spp., suggesting an even broader host range for KVP40. From these latter CDSs, an NAD salvage pathway was inferred that appears to be unique among bacteriophages. Features of the KVP40 genome that distinguish it from T4 are presented, as well as those, such as the replication and virion gene clusters, that are substantially conserved.

scholarly journals Soluble Methane Monooxygenase Gene Clusters from Trichloroethylene-Degrading Methylomonas sp. Strains and Detection of Methanotrophs during In Situ Bioremediation

1999 ◽  
Vol 65 (12) ◽  
pp. 5198-5206 ◽  
Author(s):  
Toru Shigematsu ◽  
Satoshi Hanada ◽  
Masahiro Eguchi ◽  
Yoichi Kamagata ◽  
Takahiro Kanagawa ◽  
...  
Keyword(s):  
Sequence Data ◽  
Gene Clusters ◽  
Amino Acid Sequences ◽  
Open Reading Frames ◽  
Soluble Methane Monooxygenase ◽  
Group I ◽  
Monooxygenase Gene ◽  
Group Ii ◽  
Reading Frames

ABSTRACT The soluble MMO (sMMO) gene clusters from group I methanotrophs were characterized. An 8.1-kb KpnI fragment fromMethylomonas sp. strain KSWIII and a 7.5-kbSalI fragment from Methylomonas sp. strain KSPIII which contained the sMMO gene clusters were cloned and sequenced. The sequences of these two fragments were almost identical. The sMMO gene clusters in the fragment consisted of six open reading frames which were 52 to 79% similar to the corresponding genes of previously described sMMO gene clusters of the group II and group X methanotrophs. The phylogenetic analysis of the predicted amino acid sequences of sMMO demonstrated that the sMMOs from these strains were closer to that from M. capsulatus Bath in the group X methanotrophs than to those from Methylosinus trichosporiumOB3b and Methylocystis sp. strain M in the group II methanotrophs. Based on the sequence data of sMMO genes of our strains and other methanotrophs, we designed a new PCR primer to amplify sMMO gene fragments of all the known methanotrophs harboring themmoX gene. The primer set was successfully used for detecting methanotrophs in the groundwater of trichloroethylene-contaminated sites during in situ-biostimulation treatments.

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