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

A restriction endonuclease fragment of the maxicircle of Trypanosoma brucei brucei kinetoplast DNA hybridizes with a cloned mitochondrial DNA sequence which encodes cytochrome oxidase subunit II of Zea mays. A cloned mitochondrial DNA sequence encoding cytochrome oxidase subunit II of Saccharomyces cerevisiae also hybridized with kDNA, but exhibits less homology with the maxicircle than does the maize gene. The hybridizing maxicircle DNA was localized to a 2.8 kbp segment which is bounded by TaqI restriction endonuclease sites and nearby HindIII and EcoRI restriction sites. The TaqI restriction fragment is conserved between T. brucei brucei, T. brucei rhodesiense and T. brucei gambiense and hybridizes with the Zea mays probe in each case.
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PMID:The maxicircle of Trypanosoma brucei kinetoplast DNA hybridizes with a mitochondrial gene encoding cytochrome oxidase subunit II. 628 57

The posttranscriptional insertion and deletion of U residues in trypanosome mitochondrial transcripts called RNA editing initiates at the 3' end of precisely defined editing domains that can be identified independently of the cognate guide RNA. The regions where editing initiates in Trypanosoma brucei cytochrome b and cytochrome oxidase subunit II preedited mRNAs are specifically cleaved by a trypanosome mitochondrial endonuclease that acts like mung bean nuclease and therefore is single strand specific. The regions where editing initiates in virtually all examined preedited mRNAs are predicted to form loop structures, suggesting that editing domains could generally be recognized as prominent single-stranded loops. In contrast to preedited mRNA, edited mRNA can be either resistant or sensitive to cleavage by trypanosome mitochondrial endonuclease, depending on the reaction conditions. This selectivity appears dependent on the availability of extract RNAs, and in model reactions, edited mRNA becomes resistant to cleavage upon base pairing with its guide RNA. Natural partially edited mRNAs are also specifically cleaved with a sensitivity like preedited and unlike edited mRNAs, consistent with their being intermediates in editing. These results suggest that in vivo, the structure of editing domains could initially be recognized by the mitochondrial endonuclease, which could target its associated RNA ligase and terminal U transferase to begin cycles of enzymatic editing modifications.
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PMID:Editing domains of Trypanosoma brucei mitochondrial RNAs identified by secondary structure. 753 99

Gametosomatic hybrids produced by the fusion of microspore protoplasts of Nicotiana tabacum Km(+)Sr(+) with somatic cell protoplasts of N. rustica were analysed for their organelle composition. For the analysis of mitochondrial (mt)DNA, species-specific patterns were generated by Southern hybridization of restriction endonuclease digests of total DNA and mtDNA with four DNA probes of mitochondrial origin: cytochrome oxidase subunit I, cytochrome oxidase subunit II, 26s rDNA and 5s-18s rDNA. Of the 22 hybrids analyzed, some had parental-type pattern for some probes and novel-type for the others, indicating interaction between mtDNA of the two parent species. For chloroplast (cp)DNA analysis, species-specific patterns were generated by Southern hybridization of restriction endonuclease digests of total DNA with large subunits of ribulose bisphosphate carboxylase and cpDNA as probes. All the hybrids had N. rustica-specific patterns. Hybrids were not resistant to streptomycin, a trait encoded by the chloroplast genome of N. tabacum. In gametosomatic fusions of the two Nicotiana species, mitochondria but not the chloroplasts are transmitted from the parent contributing microspore protoplasts.
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PMID:Transmission of organelles in triploid hybrids produced by gametosomatic fusions of two Nicotiana species. 2422 84