scholarly journals An intronic open reading frame was released from one of group II introns in the mitochondrial genome of the haptophyteChrysochromulinasp. NIES-1333

2014 ◽  
Vol 4 (3) ◽  
pp. e29384 ◽  
Author(s):  
Yuki Nishimura ◽  
Ryoma Kamikawa ◽  
Tetsuo Hashimoto ◽  
Yuji Inagaki
Keyword(s):  
Mitochondrial Genome ◽  
Open Reading Frame ◽  
Group Ii Introns ◽  
Reading Frame ◽  
Group Ii

scholarly journals A Group II Intron-Type Open Reading Frame from the Thermophile Bacillus (Geobacillus) stearothermophilus Encodes a Heat-Stable Reverse Transcriptase

2004 ◽  
Vol 70 (12) ◽  
pp. 7140-7147 ◽  
Author(s):  
Jaishree Vellore ◽  
Samuel E. Moretz ◽  
Bert C. Lampson
Keyword(s):  
Reverse Transcriptase ◽  
Reverse Transcription ◽  
Protein Product ◽  
Thermophilic Bacterium ◽  
Full Length ◽  
Open Reading Frame ◽  
Reading Frame ◽  
Heat Stable ◽  
Heat Stable Protein ◽  
Group Ii

ABSTRACT The production of a stable cDNA copy of an unstable RNA molecule by reverse transcription is a widely used and essential technology for many important applications, such as the construction of gene libraries, production of DNA probes, and analysis of gene expression by reverse transcriptase PCR (RT-PCR). However, the synthesis of full-length cDNAs is frequently inefficient, because the RT commonly used often produces truncated cDNAs. Synthesizing cDNA at higher temperatures, on the other hand, can provide a number of improvements. These include increasing the length of cDNA product, greater accuracy, and greater specificity during reverse transcription. Thus, an RT that remains stable and active at hot temperatures may produce better-quality cDNAs and improve the yield of full-length cDNAs. Described here is the discovery of a gene, designated trt, from the genome of the thermophilic bacterium Bacillus (Geobacillus) stearothermophilus strain 10. The gene codes for an open reading frame (ORF) similar to the ORFs encoded by group II introns found in bacteria. The gene was cloned and overexpressed in Escherichia coli, and its protein product was partially purified. Like the host organism, the Trt protein is a heat-stable protein with RT activity and can reverse transcribe RNA at temperatures as high as 75°C.

scholarly journals Detection of a Group II Intron without an Open Reading Frame in the Alpha-Toxin Gene of Clostridium perfringens Isolated from a Broiler Chicken

2006 ◽  
Vol 189 (5) ◽  
pp. 1633-1640 ◽  
Author(s):  
Menglin Ma ◽  
Kaori Ohtani ◽  
Tohru Shimizu ◽  
Naoaki Misawa
Keyword(s):  
Clostridium Perfringens ◽  
Broiler Chicken ◽  
Group Ii Intron ◽  
Open Reading Frame ◽  
Start Codon ◽  
Northern Hybridization ◽  
Toxin Gene ◽  
Alpha Toxin ◽  
Reading Frame ◽  
Group Ii

ABSTRACTA DNA insertion of 834 bp, designated CPF-G2Im, was identified within the alpha toxin gene (cpa) ofClostridium perfringensstrain CPBC16ML, isolated from a broiler chicken. Sequence analysis of CPF-G2Im indicated that it was integrated 340 nucleotides downstream of the start codon ofcpa. However, the insertion did not abolish the phospholipase C and hemolytic activities of CPBC16ML. To investigate the expression of its alpha toxin, the intact copy ofcpawas cloned into an expression vector and transformed intoEscherichia coliM15 cells. Immunoblotting analysis showed that the protein expressed from the transformant as well as in the culture supernatant ofC. perfringensstrain CPBC16ML had the expected molecular weight detected in reference strains ofC. perfringens. Northern hybridization and reverse transcriptase PCR (RT-PCR) analysis revealed that the entire CPF-G2Im insertion was completely spliced from thecpaprecursor mRNA transcripts. The sequence of the insertion fragment has 95% and 97% identity to two noncoding regions corresponding to sequences that flank a predicted group II RT gene present in the pCPF4969 plasmid ofC. perfringens. However, an RT was not encoded by the CPF-G2Im fragment. Based on the secondary structure prediction analysis, CPF-G2Im revealed typical features of group II introns. The present study shows that CPF-G2Im is capable of splicing in bothC. perfringensandE. coli. To our knowledge, this is the first report that a group II intron without an open reading frame (ORF) is located in thecpaORF ofC. perfringens.

scholarly journals Demonstration that the Group II Intron from the Clostridial Conjugative Transposon Tn5397 Undergoes Splicing In Vivo

2001 ◽  
Vol 183 (4) ◽  
pp. 1296-1299 ◽  
Author(s):  
Adam P. Roberts ◽  
Veit Braun ◽  
Christoph von Eichel-Streiber ◽  
Peter Mullany
Keyword(s):  
Bacillus Subtilis ◽  
Clostridium Difficile ◽  
Group Ii Intron ◽  
Open Reading Frame ◽  
Conjugative Transposon ◽  
Reading Frame ◽  
Circular Form ◽  
Intergeneric Transfer ◽  
Group Ii

ABSTRACT Previous work has identified the conjugative transposon Tn5397 from Clostridium difficile. This element was shown to contain a group II intron. Tn5397 can be conjugatively transferred from C. difficile toBacillus subtilis. In this work we show that the intron is spliced in both these hosts and that nonspliced RNA is also present. We constructed a mutation in the open reading frame within the intron, and this prevented splicing but did not prevent the formation of the circular form of the conjugative transposon (the likely transposition intermediate) or decrease the frequency of intergeneric transfer of Tn5397. Therefore, the intron is spliced, but splicing is not required for conjugation of Tn5397.

scholarly journals Genetic Manipulation of Lactococcus lactis by Using Targeted Group II Introns: Generation of Stable Insertions without Selection

2003 ◽  
Vol 69 (2) ◽  
pp. 1121-1128 ◽  
Author(s):  
Courtney L. Frazier ◽  
Joseph San Filippo ◽  
Alan M. Lambowitz ◽  
David A. Mills
Keyword(s):  
Lactococcus Lactis ◽  
Genetic Manipulation ◽  
Tetracycline Resistance ◽  
Group Ii Introns ◽  
Resistance Marker ◽  
Reading Frame ◽  
Conditional Expression ◽  
Genes Encoding ◽  
Group Ii ◽  
Potential Food

ABSTRACT Despite their commercial importance, there are relatively few facile methods for genomic manipulation of the lactic acid bacteria. Here, the lactococcal group II intron, Ll.ltrB, was targeted to insert efficiently into genes encoding malate decarboxylase (mleS) and tetracycline resistance (tetM) within the Lactococcus lactis genome. Integrants were readily identified and maintained in the absence of a selectable marker. Since splicing of the Ll.ltrB intron depends on the intron-encoded protein, targeted invasion with an intron lacking the intron open reading frame disrupted TetM and MleS function, and MleS activity could be partially restored by expressing the intron-encoded protein in trans. Restoration of splicing from intron variants lacking the intron-encoded protein illustrates how targeted group II introns could be used for conditional expression of any gene. Furthermore, the modified Ll.ltrB intron was used to separately deliver a phage resistance gene (abiD) and a tetracycline resistance marker (tetM) into mleS, without the need for selection to drive the integration or to maintain the integrant. Our findings demonstrate the utility of targeted group II introns as a potential food-grade mechanism for delivery of industrially important traits into the genomes of lactococci.

Plasticity of the mitochondrial genome in Podospora. Polymorphism for 15 optional sequences: group-I, group-II introns, intronic ORFs and an intergenic region

1997 ◽  
Vol 31 (4) ◽  
pp. 308-317 ◽  
Author(s):  
L. Belcour ◽  
Michèle Rossignol ◽  
France Koll ◽  
Carole H. Sellem ◽  
Catherine Oldani
Keyword(s):  
Mitochondrial Genome ◽  
Intergenic Region ◽  
Group Ii Introns ◽  
Group I ◽  
Group Ii

scholarly journals Mobile group II introns of yeast mitochondrial DNA are novel site-specific retroelements.

1995 ◽  
Vol 15 (5) ◽  
pp. 2828-2838 ◽  
Author(s):  
J V Moran ◽  
S Zimmerly ◽  
R Eskes ◽  
J C Kennell ◽  
A M Lambowitz ◽  
...  
Keyword(s):  
Group Ii Intron ◽  
Group Ii Introns ◽  
Dna Endonuclease ◽  
Site Specific ◽  
Reading Frame ◽  
Defective Mutant ◽  
Sequences Analysis ◽  
Group Ii ◽  
Precursor Rna ◽  
Yeast Mitochondrial Dna

Group II introns aI1 and aI2 of the yeast mitochondrial COXI gene are mobile elements that encode an intron-specific reverse transcriptase (RT) activity. We show here that the introns of Saccharomyces cerevisiae ID41-6/161 insert site specifically into intronless alleles. The mobility is accompanied by efficient, but highly asymmetric, coconversion of nearby flanking exon sequences. Analysis of mutants shows that the aI2 protein is required for the mobility of both aI1 and aI2. Efficient mobility is dependent on both the RT activity of the aI2-encoded protein and a separate function, a putative DNA endonuclease, that is associated with the Zn2+ finger-like region of the intron reading frame. Surprisingly, there appear to be two mobility modes: the major one involves cDNAs reverse transcribed from unspliced precursor RNA; the minor one, observed in two mutants lacking detectable RT activity, appears to involve DNA level recombination. A cis-dominant splicing-defective mutant of aI2 continues to synthesize cDNAs containing the introns but is completely defective in both mobility modes, indicating that the splicing or the structure of the intron is required. Our results demonstrate that the yeast group II intron aI2 is a retroelement that uses novel mobility mechanisms.

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