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

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1471-1477 ◽  
Author(s):  
Lewis Lukens ◽  
Huang Yicun ◽  
Georgiana May
Keyword(s):  
Mating Type ◽  
Natural Populations ◽  
Gene Clusters ◽  
Coprinus Cinereus ◽  
Noncoding Dna ◽  
Type Locus ◽  
Coding Regions ◽  
Mating Type Locus ◽  
Physical Maps ◽  
Genetic And Physical Maps

The A mating type locus of Coprinus cinereus is remarkable for its extreme diversity, with over 100 different alleles in natural populations. Classical genetic studies have demonstrated that this hypervariability arises in part from recombination between two subloci of A, alpha and beta, although more recent population genetic data have indicated a third segregating sublocus. In this study, we characterized the molecular basis by which recombination generates nonparental A mating types. We mapped the frequency and location of all recombination events in two crosses and correlated the genetic and physical maps of A. We found that all recombination events were located in 6 kb of noncoding DNA between the alpha and beta subloci and that the rate of recombination in this noncoding region matched that generally observed for this genome. No recombination within gene clusters or within coding regions was observed, and the two alpha and beta subloci described in genetic analyses correlated with the previously characterized alpha and beta gene clusters. We propose that pairs of genes constitute both the sex determining and the hereditary unit of A.

scholarly journals Multiple Versions of the A Mating Type Locus of Coprinus cinereus are Generated by Three Paralogous Pairs of Multiallelic Homeobox Genes

Genetics ◽  
1996 ◽  
Vol 144 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Eneida H Pardo ◽  
Suzanne F O'Shea ◽  
Lorna A Casselton
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Host Gene ◽  
Coprinus Cinereus ◽  
Type Locus ◽  
Multiple Alleles ◽  
Combined Analysis ◽  
Paralogous Genes ◽  
Mating Type Locus ◽  
Mating Compatibility

Abstract The A mating type locus of Coprinus cinereus determines mating compatibility by regulating essential steps in sexual development. Each A locus contains several genes separated into two functionally independent complexes termed Aα and Aβ, and the multiple alleles of these genes generate an estimated 160 A mating specificities. The genes encode two classes of homeodomain-containing proteins designated HD1 and HD2. In this report we describe two newly cloned loci, A2 and A5, and compare them with A42, A43 and A6 that we have described previously. An Aβ-null locus, retaining just a single active HD1 gene from the α-complex, was generated by mutation. Using this as a transformation host, gene combinations that promote A-regulated development were identified. We demonstrate that each A locus contains members of three paralogous pairs of HD1 and HD2 genes. Different allelic versions of gene pairs are compatible but paralogous genes are incompatible. The genes present in four uncloned A loci were deduced using Southern analyses and transformations with available cloned genes. The combined analysis of nine A factors identifies sufficient A gene alleles to generate at least 72 A mating specificities.

scholarly journals Variation at the b Mating Type Locus of Ustilago maydis

1997 ◽  
Vol 87 (12) ◽  
pp. 1233-1239 ◽  
Author(s):  
Paul Zambino ◽  
James V. Groth ◽  
Lewis Lukens ◽  
James R. Garton ◽  
Georgiana May
Keyword(s):  
Mating Type ◽  
Natural Populations ◽  
Agricultural Practices ◽  
Population Level ◽  
Ustilago Maydis ◽  
Rapid Identification ◽  
Type Locus ◽  
Mating Type Locus ◽  
B Locus ◽  
Pcr Method

Population level diversity at the Ustilago maydis b mating type locus was determined in samples from four Minnesota locations using a combination of plate mating techniques and a polymerase chain reaction (PCR)-based assay. The PCR method allows rapid identification of b types from samples of natural populations and utilizes the hypervariable regions of the b locus that determine mating type specificity. Results demonstrated high levels of b diversity within populations, with one population yielding 17 of the total 18 b types found in the study. Pairwise GST values were in the range of 0.02 to 0.05, and common b mating types were found across broad geographic distances. These data demonstrated that very low levels of differentiation among U. maydis populations occur with respect to b locus variation. Consistent with frequency-dependent selection models, b types were represented at approximately equal frequencies within the entire Minnesota population. However, neutral evolutionary models for patterns of geographic distribution and variation at b cannot be entirely excluded. The importance to agricultural practices of understanding population genetic processes is discussed.

A Large Pheromone and Receptor Gene Complex Determines Multiple B Mating Type Specificities in Coprinus cinereus

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 1081-1090
Author(s):  
Suzanne F O'Shea ◽  
Pushpalata T Chaure ◽  
John R Halsall ◽  
Natalie S Olesnicky ◽  
Andreas Leibbrandt ◽  
...  
Keyword(s):  
Mating Type ◽  
Receptor Gene ◽  
Transmembrane Helix ◽  
Coprinus Cinereus ◽  
Specific Sequence ◽  
Cross Hybridization ◽  
Type Locus ◽  
Mating Type Locus ◽  
Pheromone Signaling ◽  
Genes Encoding

Abstract Pheromone signaling plays an essential role in the mating and sexual development of mushroom fungi. Multiallelic genes encoding the peptide pheromones and their cognate 7-transmembrane helix (7-TM) receptors are sequestered in the B mating type locus. Here we describe the isolation of the B6 mating type locus of Coprinus cinereus. DNA sequencing and transformation analysis identified nine genes encoding three 7-TM receptors and six peptide pheromone precursors embedded within 17 kb of mating type-specific sequence. The arrangement of the nine genes suggests that there may be three functionally independent subfamilies of genes each comprising two pheromone genes and one receptor gene. None of the nine B6 genes showed detectable homology to corresponding B gene sequences in the genomic DNA from a B3 strain, and each of the B6 genes independently alter B mating specificity when introduced into a B3 host strain. However, only genes in two of the B6 groups were able to activate B-regulated development in a B42 host. Southern blot analysis showed that these genes failed to cross-hybridize to corresponding genes in the B42 host, whereas the three genes of the third subfamily, which could not activate development in the B42 host, did cross-hybridize. We conclude that cross-hybridization identifies the same alleles of a particular subfamily of genes in different B loci and that B6 and B42 share alleles of one subfamily. There are an estimated 79 B mating specificities: we suggest that it is the different allele combinations of gene subfamilies that generate these large numbers.

scholarly journals rme1 Mutation of Saccharomyces cerevisiae: map position and bypass of mating type locus control of sporulation.

1981 ◽  
Vol 1 (10) ◽  
pp. 958-960 ◽  
Author(s):  
J Rine ◽  
G F Sprague ◽  
I Herskowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Type Locus ◽  
Mating Type Locus ◽  
Type Information

Sporulation in Saccharomyces cerevisiae normally occurs only in MATa/MAT alpha diploids. We show that mutations in RME1 bypassed the requirements for both a and alpha mating type information in sporulation and therefore allowed MATa/MATa and MAT alpha/MAT alpha diploids to sporulate. RME1 was located on chromosome VII, between LEU1 and ADE6.

Transformation of protoplasted yeast cells is directly associated with cell fusion

1984 ◽  
Vol 4 (4) ◽  
pp. 771-778
Author(s):  
S Harashima ◽  
A Takagi ◽  
Y Oshima
Keyword(s):  
Cell Fusion ◽  
Mating Type ◽  
Nuclear Fusion ◽  
Yeast Cells ◽  
Nuclear Markers ◽  
Type Locus ◽  
Mating Type Locus ◽  
Yeast Protoplasts ◽  
Yeast Plasmids ◽  
Binominal Distribution

The frequency of cell fusion during transformation of yeast protoplasts with various yeast plasmids with a chromosome replicon (YRp or YCp) or 2 mu DNA (YEp) was estimated by two methods. In one method, a mixture of protoplasts of two haploid strains with identical mating type and complementary auxotrophic nuclear markers with or without cytoplasmic markers was transformed. When the number of various phenotypic classes of transformants for the nuclear markers was analyzed by equations derived from binominal distribution theory, the frequency of nuclear fusion among the transformants was 42 to 100% in transformations with the YRp or YCp plasmids and 28 to 39% with the YEp plasmids. In another method, a haploid bearing the sir mutation, which allows a diploid (or polyploid) homozygous for the MAT (mating type) locus to sporulate by the expression of the silent mating-type loci HML and HMR, was transformed with the plasmids. Sporulation ability was found in 43 to 95% of the transformants with the YRp or YCp plasmids, and 26 to 31% of the YEp transformants. When cytoplasmic mixing was included with the nuclear fusion, 96 to 100% of the transformants were found to be cell fusants. Based upon these observations, we concluded that transformation of yeast protoplasts is directly associated with cell fusion.

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