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Inhibition Of Chloroplast Dna Recombination And Repair By Dominant Negative Mutants Of Escherichia Coli Reca, Heriberto D. Cerutti, Anita M. Johnson, John E. Boynton, Nicholas W. Gillham
Inhibition Of Chloroplast Dna Recombination And Repair By Dominant Negative Mutants Of Escherichia Coli Reca, Heriberto D. Cerutti, Anita M. Johnson, John E. Boynton, Nicholas W. Gillham
Center for Plant Science Innovation: Faculty and Staff Publications
Escherichia coli RecA, suggest that the plastid recombination system is related to its eubacterial counterpart. Therefore, we examined whether dominant negative mutants of the E. coli RecA protein can interfere with the activity of their putative homolog in the chloroplast of the unicellular green alga Chlamydomonas reinhardtii. Transformants expressing these mutant RecA proteins showed reduced survival rates when exposed to DNA-damaging agents, deficient repair of chloroplast DNA, and diminished plastid DNA recombination. These results strongly support the existence of a RecA-mediated recombination system in chloroplasts. We also found that the wild-type E. coli RecA protein enhances the frequency of …
Movement Of Dna Across The Chloroplast Envelope: Implications For The Transfer Of Promiscuous Dna, Heriberto D. Cerutti, André Jagendorf
Movement Of Dna Across The Chloroplast Envelope: Implications For The Transfer Of Promiscuous Dna, Heriberto D. Cerutti, André Jagendorf
Center for Plant Science Innovation: Faculty and Staff Publications
Little is known about the mechanistic basis for the movement of promiscuous nucleic acids across cell membranes. To address this problem we sought conditions that would permit the entry of plasmid DNA into isolated, intact pea chloroplasts. DNA uptake did not occur normally, but was induced by hypotonic treatments, by incubation with millimolar levels of Mg2+, or by heat shock at 42 °C. These results are consistent with DNA movement being permitted by conditions that transiently alter the permeability of the chloroplast envelope. Plant cells are subject to osmotic tensions and/or conditions inducing polymorphic changes in the membranes, …