Recent attempts to characterise the hybrid strains of Cryptococcus neoformans have led to the identification of a cryptic population of hybrid strains ('H strains') with double DNA content but only a single mating-type allele. To verify a set of hypotheses concerning their origin, we investigated 14 previously isolated H strains and ten F1-progeny strains arising from H99 and JEC20 mating. The double DNA content was tested by flow cytometry; the presence of only one mating type was tested by amplifying 12 mating-type-specific genes and one gene unlinked with the mating-type locus (URA5). Analysis of the F1 progeny identified two H strains, and electrophoretic karyotyping confirmed the occurrence of genetic recombination. The simultaneous presence of the homozygous and heterozygous loci, and the fact that all of the F1-progeny strains presented a recombinant karyotype, suggest that the H strains originated from the post-meiotic random fusion of two of the four recombinant nuclei. Further studies are required to elucidate the role of the homozygous mating-type loci in the virulence of C. neoformans.

Cryptococcus neoformans population includes hybrid strains homozygous at mating-type locus / M. Cogliati, M.C. Esposto, A.M. Tortorano, M..A. Viviani. - In: FEMS YEAST RESEARCH. - ISSN 1567-1356. - 6:4(2006 Jun), pp. 608-613.

Cryptococcus neoformans population includes hybrid strains homozygous at mating-type locus

M. Cogliati;M.C. Esposto;A.M. Tortorano;
2006-06

Abstract

Recent attempts to characterise the hybrid strains of Cryptococcus neoformans have led to the identification of a cryptic population of hybrid strains ('H strains') with double DNA content but only a single mating-type allele. To verify a set of hypotheses concerning their origin, we investigated 14 previously isolated H strains and ten F1-progeny strains arising from H99 and JEC20 mating. The double DNA content was tested by flow cytometry; the presence of only one mating type was tested by amplifying 12 mating-type-specific genes and one gene unlinked with the mating-type locus (URA5). Analysis of the F1 progeny identified two H strains, and electrophoretic karyotyping confirmed the occurrence of genetic recombination. The simultaneous presence of the homozygous and heterozygous loci, and the fact that all of the F1-progeny strains presented a recombinant karyotype, suggest that the H strains originated from the post-meiotic random fusion of two of the four recombinant nuclei. Further studies are required to elucidate the role of the homozygous mating-type loci in the virulence of C. neoformans.
Settore MED/42 - Igiene Generale e Applicata
FEMS YEAST RESEARCH
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1567-1364.2006.00085.x
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/25096
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