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 Mating Type Protein Mat1-2 from Asexual Aspergillus fumigatus Drives Sexual Reproduction in Fertile Aspergillus nidulans

2008 ◽  
Vol 7 (6) ◽  
pp. 1029-1040 ◽  
Author(s):  
Wioletta Pyrzak ◽  
Karen Y. Miller ◽  
Bruce L. Miller
Keyword(s):  
Aspergillus Fumigatus ◽  
Aspergillus Nidulans ◽  
Mating Type ◽  
Sexual Development ◽  
Genetic System ◽  
Gene Replacement ◽  
Sexual Cycle ◽  
Homologous Gene ◽  
Gene Exchange ◽  
First Report

ABSTRACT The lack of an experimentally amenable sexual genetic system in Aspergillus fumigatus is a major limitation in the study of the organism's pathogenesis. A recent comparative genome analysis revealed evidence for potential sexuality in A. fumigatus. Homologs of mating type genes as well as other genes of the “sexual machinery” have been identified in anamorphic A. fumigatus. The mat1-2 gene encodes a homolog of MatA, an HMG box mating transcriptional factor (MatHMG) that regulates sexual development in fertile Aspergillus nidulans. In this study, the functionalities of A. fumigatus mat1-2 and the Mat1-2 protein were determined by interspecies gene exchange between sterile A. fumigatus and fertile A. nidulans. Ectopically integrated A. fumigatus mat1-2 (driven by its own promoter) was not functional in a sterile A. nidulans ΔmatA strain, and no sexual development was observed. In contrast, the A. fumigatus mat1-2 open reading frame driven by the A. nidulans matA promoter and integrated by homologous gene replacement at the matA locus was functional and conferred full fertility. This is the first report showing that cross species mating type gene exchange between closely related Ascomycetes did not function in sexual development. This is also the first report demonstrating that a MatHMG protein from an asexual species is fully functional, with viable ascospore differentiation, in a fertile homothallic species. The expression of mat1-2 was assessed in A. fumigatus and A. nidulans. Our data suggest that mat1-2 may not be properly regulated to allow sexuality in A. fumigatus. This study provides new insights about A. fumigatus asexuality and also suggests the possibility for the development of an experimentally amenable sexual cycle.

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  +.

scholarly journals Mating-Type-Specific and Nonspecific PAK Kinases Play Shared and Divergent Roles in Cryptococcus neoformans

2002 ◽  
Vol 1 (2) ◽  
pp. 257-272 ◽  
Author(s):  
Ping Wang ◽  
Connie B. Nichols ◽  
Klaus B. Lengeler ◽  
Maria E. Cardenas ◽  
Gary M. Cox ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Mating Type ◽  
Fungal Pathogen ◽  
Sexual Cycle ◽  
Type Locus ◽  
Serotype A ◽  
A Cells ◽  
Genes Encoding ◽  
Opportunistic Fungal Pathogen ◽  
Synthetically Lethal

ABSTRACT Cryptococcus neoformans is an opportunistic fungal pathogen with a defined sexual cycle involving fusion of haploid MATα and MATa cells. Virulence has been linked to the mating type, and MATα cells are more virulent than congenic MATa cells. To study the link between the mating type and virulence, we functionally analyzed three genes encoding homologs of the p21-activated protein kinase family: STE20α, STE20a, and PAK1. In contrast to the STE20 genes that were previously shown to be in the mating-type locus, the PAK1 gene is unlinked to the mating type. The STE20α, STE20a, and PAK1 genes were disrupted in serotype A and D strains of C. neoformans, revealing central but distinct roles in mating, differentiation, cytokinesis, and virulence. ste20α pak1 and ste20a pak1 double mutants were synthetically lethal, indicating that these related kinases share an essential function. In summary, our studies identify an association between the STE20α gene, the MATα locus, and virulence in a serotype A clinical isolate and provide evidence that PAK kinases function in a MAP kinase signaling cascade controlling the mating, differentiation, and virulence of 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 Elucidation of the determinant for orchestration of solo unisexual cycle in an important human fungal pathogen

2019 ◽  
Author(s):  
Pengjie Hu ◽  
Huimin Liu ◽  
Lei Chen ◽  
Guang-Jun He ◽  
Xiuyun Tian ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sexual Development ◽  
Fungal Pathogen ◽  
Model Organism ◽  
Sexual Cycle ◽  
Critical Determinant ◽  
Human Fungal Pathogen ◽  
Alternative Approach ◽  
Sexual Determination ◽  
Functional Profiling

AbstractIn fungi, the sex-determination program universally directs sexual development and syngamy (the fusion of gametes) that underlies pre-meiotic diploidization. However, the contribution of sex-determination to syngamy-independent sexual cycle, which requires autopolyploidization as an alternative approach to elevate ploidy before meiosis, remains unclear in fungi and other eukaryotes. The human fungal pathogen Cryptococcus neoformans, as a model organism for studying fungal sexual reproduction, can undergo syngamy-dependent bisexual and syngamy-independent solo unisexual reproduction, in which endoreplication is considered to enable pre-meiotic self-diploidization. Here, by characterizing a mutant lacking all the core sex-determination factors, we show that sex-determination plays a central role in bisexual syngamy but is not strictly required for unisexual development and self-diploidization. This implies an unknown circuit, rather than the sex-determination program, for specifically coordinating Cryptococcus unisexual cycle. We reveal that syngamy and self-diploidization are both governed by the Qsp1-directed paracrine system via two regulatory branches, Vea2 and Cqs2. Vea2 directs bisexual syngamy through the sex-determination program; conversely, Cqs2 is dispensable for bisexual syngamy but activates unisexual endoreplication. Through functional profiling of 41 transcription factors documented to regulate Cryptococcus sexual development, we reveal that only Cqs2 can drive and integrate all unisexual phases and ensure the production of meiospore progenies. Furthermore, ChIP-seq analysis together with genetic evaluation indicate that Cqs2 induces unisexual self-diploidization through its direct control of PUM1, whose expression is sufficient to drive autopolyploidization. Therefore, Cqs2 serves as the critical determinant that orchestrates Cryptococcus multistage unisexual cycle that does not strictly require the sexual-determination program.

Sign in / Sign up

Export Citation Format

Share Document