Genome rearrangement and nitrogen fixation in Anabaena blocked by inactivation of xisA gene

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Science  09 Dec 1988:
Vol. 242, Issue 4884, pp. 1421-1423
DOI: 10.1126/science.3144039


Two genome rearrangements involving 11- and 55-kilobase DNA elements occur during the terminal differentiation of an Anabaena photosynthetic vegetative cell into a nitrogen-fixing heterocyst. The xisA gene, located on the nifD 11-kilobase DNA element, was inactivated by recombination between the chromosome and a copy of the xisA gene that was mutated by inserting an antibiotic gene cassette. Site-directed inactivation of the Anabaena xisA gene blocked rearrangement of the 11-kilobase element and nitrogen fixation, but did not affect rearrangement of the 55-kilobase element, heterocyst differentiation, or heterocyst pattern formation.

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