Molecular analysis of the Coprinus cinereus mating type A factor demonstrates an unexpectedly complex structure.

Abstract

We report here the molecular cloning of the A43 mating type factor from Coprinus cinereus, a basidiomycetous fungus. Our molecular analyses revealed an unexpected source of variation in the A factor. Though genetic studies have demonstrated that A has two subunits, alpha and beta, we located three nonoverlapping fragments in the A43 region that have A factor function following DNA-mediated transformation. The three fragments demonstrate no similarity to one another as judged by restriction enzyme maps and by hybridization on Southern blots. We conclude that the A43 factor is composed of at least three subunits. When strains carrying different A factors are examined by hybridization to the cloned subunits, extensive polymorphism is seen. Both intensity of hybridization and restriction fragment lengths vary between strains. Some strains fail to show any hybridization to a probe. In contrast, other strains from widely separated geographic locations apparently share very similar subunits. From comparative restriction enzyme mapping of A43 and a mutated A43 factor, we inferred that a 12-kb deletion in the A factor was responsible for the constitutive, dominant phenotype of the mutated A factor. The results of transformation experiments support an activator model for the activity of the A factor in regulating the A pathway.

Correlation of Genetic and Physical Maps at the A Mating-Type Locus of Coprinus cinereus

“…Mating system: In the dikaryon, the A locus controls the synchronized division of parental nuclei and the initiation of the clamp cell (SWIEZYNSKI and DAY 1960a). Only one gene pair in A must be different from its homologue's counterpart for sexual reproduction to proceed (MAY et al 1991;KUES et al 1992). Fully compatible matings and complete sexual development require that the two mating haploids must also differ at B, which controls clamp cell fusion and nuclear migration.…”

“…These regions have been termed the alpha and beta gene clusters to correspond to DAY'S description of the locus. An allelic difference at any gene pair between two mating strains is sufficient for compatibility (MAY et al 1991;KUES et al 1992). However, a view of the A locus as having two segregating subloci conflicts with results of population genetic analyses, which have demonstrated that three subloci segregate in natural populations.…”

“…We recovered recombinant A mating type loci from two different crosses and calculated recombination frequencies. The positions of recombination events were then mapped using probes derived from the A mating type region (MAY et al 1991). All recombination events occurred in only one, noncoding region of the A mating type locus between the alpha and beta gene clusters.…”

Development of a Basic Biosensor System for Wood Degradation using Volatile Organic Compounds

“…C. cinerea strain AmutBmut (A43mut, B43mut, pab1), a self-compatible homokaryon that forms fruiting body and oidia in a light-regulated manner (Swamy et al 1984;May et al 1991;Kertesz-Chaloupková et al 1998;, was used for investigating VOCs released during life cycle development.…”

Analise genomica do sistema mating type de Crinipellis perniciosa, fungo causador da vassoura-de-bruxa em Theobroma cacao

“…Da mesma forma que em S. commune, em Coprinus cinereus foram identificados no locus A (HD) dois sub loci, o sub locus A alfa e o sub locus A beta Sua organização molecular é mais conhecida devido ao fato desse sub-loci estarem muito próximos, o que permitiu o seu isolamento molecular como um todo (Mutasa et al 1990;May et al 1991;Pardo et al 1996).…”