Topological linkage of circular DNA molecules promoted by Ustilago recl protein and topoisomerase

Kmiec, Eric B.; Kroeger, Paul E.; Brougham, M.J.; Holloman, William K.

doi:10.1016/0092-8674(83)90549-4

Cited by 24 publications

(11 citation statements)

References 50 publications

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“…In model studies with purified reel protein of the lower eukaryote U. maydis (a fungus) and topoisomerase I of the same organism, it has indeed been shown that a paranemic joint between two homologous DNA strands within a recombinational synapsis can be converted into a plectonemic joint by the topoisomerase I (KMIEC et al 1983;KMIEC and HOLLOMAN 1984). The reel protein of U. maydis has a similar function in recombination as the recA protein of E. coli (KMIEC and HOLLOMAN 1982).…”

Section: Eukaryotic Topoisomerasesmentioning

confidence: 96%

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DNA Topoisomerases: Enzymes That Control DNA Conformation

Vosberg

1985

Current Topics in Microbiology and Immunology

234

166

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Section: Eukaryotic Topoisomerasesmentioning

confidence: 96%

“…Spermidine, present at a concentration of 5 mM as a DNA condensing agent, is favorable or may even be essential for this reaction . Similar to the E. coli co-protein, a eukaryotic topoisomerase I (of U. maydis) has been shown to catalyze the conversion of a paranemic to a plectonemic joint (KMIEC et al 1983).…”

Section: Eukaryotic Type I Topoisomerasesmentioning

confidence: 99%

DNA Topoisomerases: Enzymes That Control DNA Conformation

Vosberg

1985

Current Topics in Microbiology and Immunology

234

166

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“…Homologous pairing was not blocked by topological barriers that would preclude true heteroduplex formation and strand intertwining. Pairing proceeded between a single-stranded circle and homologous superhelical DNA (21) or with single-stranded circular molecules and linear duplexes containing homologous sequences flanked by long stretches of heterology (17). Pairing activity was also observed between two duplex circles under conditions in which there was either active transcription, a previously formed D loop, or else the presence of DNA sequences with the potential to flip to the Z-DNA form (18,21).…”

mentioning

confidence: 90%

“…Pairing proceeded between a single-stranded circle and homologous superhelical DNA (21) or with single-stranded circular molecules and linear duplexes containing homologous sequences flanked by long stretches of heterology (17). Pairing activity was also observed between two duplex circles under conditions in which there was either active transcription, a previously formed D loop, or else the presence of DNA sequences with the potential to flip to the Z-DNA form (18,21). Studies reporting purification of strand exchange activities from a variety of other eukaryotic sources have also been made, but with the exception of the activity from U. maydis, there has been no documented example of an ATP-dependent activity (for a review, see reference 23).…”

mentioning

confidence: 99%

The REC2 gene encodes the homologous pairing protein of Ustilago maydis.

Kmiec¹,

Cole²,

Holloman³

1994

Mol. Cell. Biol.

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Amino acid sequence analysis has established that the homologous pairing protein of Ustilago maydis, known previously in the literature as recl, is encoded by REC2, a gene essential for recombinational repair and meiosis with regional homology to Escherichia coli RecA. The 70-kDa recl protein is most likely a proteolytic degradation product of REC2, which has a predicted mass of 84 kDa but which runs anomalously during sodium dodecyl sulfate-gel electrophoresis with an apparent mass of 110 kDa. To facilitate purification of the protein product, the REC2 gene was overexpressed from a vector that fused a hexahistidine leader sequence onto the amino terminus, enabling isolation of the REC2 protein on an immobilized metal alfinity column. The purified protein exhibits ATP-dependent DNA renaturation and DNA-dependent ATPase activities, which were reactions characteristic of the protein as purified from cell extracts of U. maydis. Homologous pairing activity was established in an assay that measures recognition via non-Watson-Crick bonds between identical DNA strands. A size threshold of about 50 bp was found to govern pairing between linear duplex molecules and homologous single-stranded circles. Joint molecule formation with duplex DNA well under the size threshold was efficiently catalyzed when one strand of the duplex was composed of RNA. Linear duplex molecules with hairpin caps also formed joint molecules when as few as three RNA residues were present.Genetic recombination can be envisioned as a pathway that proceeds stepwise through a search for sequence homology, DNA pairing, heteroduplex formation, and exchange of strands. Elucidation of the process has come in part from detailed analysis of Escherichia coli RecA protein. Studies on the biochemical mechanism have revealed the protein to catalyze homologous pairing of DNA molecules in a reaction that transduces the energy of nucleotide cofactor binding to changing conformational states of the protein and to promote strand exchange by coupling nucleotide hydrolysis to unidirectional processing of the crossed-strand recombination intermediate (22,24,25,28,38). The RecA protein has become the paradigm for thinking about the mechanism of DNA pairing in general homologous recombination. The ubiquity of RecA in bacteria has reinforced the hope that lessons learned from studies of this prototype system may be extended beyond the realm of prokaryotes.Evidence supporting the notion that eukaryotes might conduct recombination through a RecA-like DNA pairing mechanism has come from two approaches. Genetic studies led to the discovery, first made in Saccharomyces cerevisiae (1,2,5,14,30) and later in other eukaryotes, of proteins homologous to RecA (for a review, see reference 11). On the other hand, biochemical studies with Ustilago maydis revealed the presence of an activity that could promote a number of DNA pairing reactions, some of which resembled reactions catalyzed by RecA protein (15). These included ATP-stimulated reassociation of complementary single strands, u...

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“…When the participating genomes are circular, the (4)(5)(6)(7)(8)(9)(10). The enzymology ofthe formation and resolution of Holliday structures is not well understood, but the RecA and Recl proteins, from E. coli and Ustilago maydis, respectively, probably play a role in the formation of Holliday junctions in these organisms (11,12). Resolution of the Holliday junction requires cleavage of the crossed strands, realignment, and ligation to generate an intact recombinant duplex.…”

mentioning

confidence: 99%

Partial purification of an enzyme from Saccharomyces cerevisiae that cleaves Holliday junctions.

Kolodner¹

1985

Proc. Natl. Acad. Sci. U.S.A.

113

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An enzyme from Saccharomyces cerevisiae that cleaves Holliday junctions was partially purified W500-to 1000-fold by DEAE-cellulose chromatography, gel filtration on Sephacryl S300, and chromatography on single-stranded DNAcellulose. The partially purified enzyme did not have any detectable nuclease activity when tested with single-stranded or double-stranded bacteriophage T7 substrate DNA and did not have detectable endonuclease activity when tested with bacteriophage M13 viral DNA or plasmid pBR322 covalently closed circular DNA. Analysis of the products of the cruciform cleavage reaction by electrophoresis on polyacrylamide gels under denaturing conditions revealed that the cruciform structure was cleaved at either of two sites present in the stem of the cruciform and was not cleaved at the end of the stem. The cruciform cleavage enzyme was able to cleave the Holliday junction present in bacteriophage G4 figure-8 molecules.

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Topological linkage of circular DNA molecules promoted by Ustilago recl protein and topoisomerase

Cited by 24 publications

References 50 publications

DNA Topoisomerases: Enzymes That Control DNA Conformation

DNA Topoisomerases: Enzymes That Control DNA Conformation

The REC2 gene encodes the homologous pairing protein of Ustilago maydis.

Partial purification of an enzyme from Saccharomyces cerevisiae that cleaves Holliday junctions.

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