scholarly journals MATING-TYPE MUTATIONS IN SCHIZOSACCHAROMYCES POMBE: ISOLATION OF MUTANTS AND ANALYSIS OF STRAINS WITH AN h  - or h  + PHENOTYPE

Genetics ◽  
1976 ◽  
Vol 83 (2) ◽  
pp. 259-273
Author(s):  
James H Meade ◽  
Herbert Gutz
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Gene Product ◽  
Mating Type ◽  
Sexual Cycle ◽  
Type Region ◽  
Type Allele ◽  
Mating Type Gene ◽  
Auxiliary Gene ◽  
Type Gene

ABSTRACT Mutants defective in various steps of the sexual cycle have been isolated from homothallic strains of Schizosaccharomyces pombe by Bresch, Müller and Egel (1968). These mutants include heterothallic h  + and h  - strains. We have isolated additional h  + and h  -mutants from homothallic strains. Those mutants which are due to mutations in the mating-type region were analyzed in detail. Our results show that the mating-type gene mat2 not only has a function in copulation and meiosis, but that it also regulates the formation of the map1 gene product (map1 is a mating-type auxiliary gene). Some of the h  - mutants have lost only one of the three functions while others are defective in at least two, and perhaps all three, functions. Further, we show that the mat1  - allele of h90 strains can mutate to mat1  + but that mutations in mat2 appear to affect the mutational behavior of mat1. Finally, we describe a new inactive mating-type allele, mat2*, which is different from mat2  0 in that it can mutate to mat2  +.

BEHAVIOUR OF NEUROSPORA TETRASPERMA MATING-TYPE GENES INTROGRESSED INTO N. CRASSA

1973 ◽  
Vol 15 (3) ◽  
pp. 571-576 ◽  
Author(s):  
Robert L. Metzenberg ◽  
Sandra K. Ahlgren
Keyword(s):  
Mating Type ◽  
Genetic Background ◽  
Opposite Mating Type ◽  
Type Allele ◽  
Mating Type Gene ◽  
Mating Type Genes ◽  
Type Gene ◽  
Neurospora Tetrasperma ◽  
Do So

The two alleles of the mating-type gene of Neurospora tetrasperma have been introgressed into a largely N. crassa genetic background. Under these circumstances, they are no longer able to coexist without inhibition in heterocaryons, nor can they do so with their opposite mating-type allele from N. crassa. Neither are they compatible with the latter in partial diploids heterozygous for the mating-type alleles. The implications of this are briefly discussed.

scholarly journals The Asexual Pathogen Aspergillus fumigatus Expresses Functional Determinants of Aspergillus nidulans Sexual Development

2008 ◽  
Vol 7 (10) ◽  
pp. 1724-1732 ◽  
Author(s):  
Verena Große ◽  
Sven Krappmann
Keyword(s):  
Aspergillus Fumigatus ◽  
Aspergillus Nidulans ◽  
Gene Product ◽  
Mating Type ◽  
Sexual Development ◽  
Fungal Pathogen ◽  
Sexual Cycle ◽  
Genes Encoding ◽  
Type Gene ◽  
High Level

ABSTRACT The major fungal pathogen of humans, Aspergillus fumigatus, lacks a defined sexual cycle, although the presence of genes encoding putative mating type idiomorphs and regulators of Aspergillus sexual development heightens the potential for cryptic sexuality in this deuteromycete. To test the functionality of these genetic determinants, we transferred the alpha box-encoding mat1-1 idiomorph from an A. fumigatus isolate to the homothallic fertile species Aspergillus nidulans. Abundant formation of fruiting bodies (cleistothecia) containing viable ascospores establishes functionality of this mating type gene product in the transgenic strain. Using a similar approach, we also established that the conserved transcriptional regulator from A. fumigatus, the nsdD gene product, can act as a functional, positively acting factor for A. nidulans cleistothecium development; moreover, high-level expression of NsdD in the endogenous host A. fumigatus profoundly alters hyphal development by triggering the formation of coiled hyphae. Our findings demonstrate that the presumably asexual pathogen A. fumigatus encodes functional regulators of mating and sexual development, thereby potentiating the case for cryptic sexuality in this fungal pathogen.

scholarly journals Deletion of the Schizophyllum commune Aα Locus: The Roles of Aα Y and Z Mating-Type Genes

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1437-1444
Author(s):  
C Ian Robertson ◽  
Kirk A Bartholomew ◽  
Charles P Novotny ◽  
Robert C Ullrich
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Schizophyllum Commune ◽  
Mating Types ◽  
Developmental Pathway ◽  
Mating Type Gene ◽  
Mating Type Genes ◽  
Regulatory Loci ◽  
Type Gene

The Aα locus is one of four master regulatory loci that determine mating type and regulate sexual development in Schizophyllum commune. We have made a plasmid containing a URA1 gene disruption of the Aα Y1 gene. Y1 is the sole Aα gene in Aα1 strains. We used the plasmid construction to produce an Aα null (i.e., AαΔ) strain by replacing the genomic Y1 gene with URA1 in an Aα1 strain. To characterize the role of the Aα genes in the regulation of sexual development, we transformed various Aα Y and Z alleles into AαΔ strains and examined the acquired mating types and mating abilities of the transformants. These experiments demonstrate that the Aα Y gene is not essential for fungal viability and growth, that a solitary Z Aα mating-type gene does not itself activate development, that Aβ proteins are sufficient to activate the A developmental pathway in the absence of Aα proteins and confirm that Y and Z genes are the sole determinants of Aα mating type. The data from these experiments support and refine our model of the regulation of A-pathway events by Y and Z proteins.

scholarly journals The sum1-1 mutation affects silent mating-type gene transcription in Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (1) ◽  
pp. 409-412 ◽  
Author(s):  
G P Livi ◽  
J B Hicks ◽  
A J Klar
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Transcriptional Control ◽  
Gene Mutations ◽  
State Level ◽  
Mating Type Gene ◽  
Gene Transcripts ◽  
Mating Type Genes ◽  
Type Gene ◽  
Type Information

The silent mating-type genes (HML and HMR) of Saccharomyces cerevisiae are kept under negative transcriptional control by the trans-acting products of the four MAR/SIR loci. MAR/SIR gene mutations result in the simultaneous derepression of HML and HMR gene expression. The sum1-1 mutation was previously identified as an extragenic suppressor of mutations in MAR1 (SIR2) and MAR2 (SIR3). As assayed genetically, sum1-1 is capable of restoring repression of silent mating-type information in cells containing mar1 or mar2 null mutations. We show here that the mating-type phenotype associated with sum1-1 results from a dramatic reduction in the steady-state level of HML and HMR gene transcripts. At the same time, the sum1-1 mutation has no significant effect on the level of each of the four MAR/SIR mRNAs.

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