Formation of a minichromosome in Cryptococcus neoformans as a result of electroporative transformation.
A minichromosome of approximately 270 kilobases was generated following complementation of a ura5 mutant strain of C. neoformans with the plasmid pURA5g2. This is the first report of the in-vivo generation of a minichromosome by the method of electroporative transformation. The minichromosome occurred at a relatively high (> 20%) frequency in transformants that were stable for uracil protoprophy. The minichromosome was maintained in linear form as a large extrachromosomal element of the normal karyotype. Gel-purified DNA from the minichromosome readily transformed the ura5 mutant of C. neoformans. Southern-blot analysis of the minichromosome revealed the presence of multiple copies of the URA5 gene and ribosomal DNA sequences in addition to containing telomere-like sequence repeats. The minichromosome was transmitted through mitosis and meiosis with extremely-high fidelity.
Varma
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Clinical Mycology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
Kwon-Chung
K J
KJ
D001483:Base Sequence; D015139:Blotting, Southern; D015825:Chromosomes, Fungal; D003455:Cryptococcus neoformans / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D018274:Electroporation; D008969:Molecular Sequence Data; D014170:Transformation, Genetic
D004271:DNA, Fungal