Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mobile group II introns aI1 and aI2 of yeast mtDNA encode endonuclease activities that cleave intronless DNA target sites to initiate mobility by target DNA-primed reverse transcription. For aI2, sense-strand cleavage occurs mainly by a partial reverse splicing reaction, whereas for aI1, complete reverse splicing occurs, leading to insertion of the linear intron RNA into double-stranded DNA. Here, we show that aI1 homing and reverse splicing depend on the EBS1 (RNA)/IBS1(DNA) pairing and that target specificity can be changed by compensatory changes in the target site and the donor intron. Using well-marked strains to follow coconversion of flanking DNA, we show that homing occurs by both RT-dependent and -independent pathways. Remarkably, in most RT-dependent events, the reverse spliced intron is the initial template for first-strand cDNA synthesis.
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PMID:Mobility of yeast mitochondrial group II introns: engineering a new site specificity and retrohoming via full reverse splicing. 911 29

We describe herein a large group-II intron which is inserted in the mitochondrial cox1 gene of the Schizosaccharomyces pombe strain EF2. The intron RNA consists of 2492 nucleotides which can be folded into a secondary structure with all the expected sequence motifs of subgroup-IIA1 introns (Michel et al. 1989). Determination of the exact splice point revealed that the intron is inserted in the same codon, but 1 bp downstream, as the mobile intron aI2 in the Saccharomyces cerevisiae cox1 homologue. A total of nine nucleotide changes was observed around the insertion site of the intron in the cox1 gene of strain EF2 compared with the reference strain ade7-50h(-). Seven of these changes are clustered within the 51 bp upstream of the splice point. Only one sequence deviation was found in the downstream exon. The intron is capable of splicing despite the fact that both the EBS1/IBS1 and the EBS2/IBS2 sequence motifs, thought to be necessary for correct splicing, extend over 5 instead of 6 bp. The maturase, endonuclease and reverse transcriptase domains of the putative protein encoded by the newly described S. pombe group-II intron were not closer to those encoded by the other two, cobI and cox2I, S. pombe group-II introns than to the group-II intron-encoded proteins in Allomyces, Marchantia, Podospora and Saccharomyces.
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PMID:A novel group-II intron in the cox1 gene of the fission yeast Schizosaccharomyces pombe is inserted in the same codon as the mobile group-II intron aI2 in the Saccharomyces cerevisiae cox1 homologue. 1046 4