The mating-type locus B alpha 1 of Schizophyllum commune contains a pheromone receptor gene and putative pheromone genes.

The B mating-type locus of Lentinula edodes, a representative edible mushroom, is highly complex because of allelic variations in the mating pheromone receptors (RCBs) and the mating pheromones (PHBs) in both the Bα and Bβ subloci. The complexity of the B mating-type locus, five Bα subloci with five alleles of RCB1 and nine PHBs and three Bβ subloci with 3 alleles of RCB2 and five PHBs, has led us to investigate the specificity of the PHB–RCB interaction because the interaction plays a key role in non-self-recognition. In this study, the specificities of PHBs to RCB1-2 and RCB1-4 from the Bα sublocus and RCB2-1 from the Bb sublocus were investigated using recombinant yeast strains generated by replacing STE2, an endogenous yeast mating pheromone receptor, with the L. edodes RCBs. Fourteen synthetic PHBs with C-terminal carboxymethylation but without farnesylation were added to the recombinant yeast cells and the PHB–RCB interaction was monitored by the expression of the FUS1 gene—a downstream gene of the yeast mating signal pathway. RCB1-2 (Bα2) was activated by PHB1 (4.3-fold) and PHB2 (2.1-fold) from the Bα1 sublocus and RCB1-4 (Bα4) was activated by PHB5 (3.0-fold) and PHB6 (2.7-fold) from the Bα2 sublocus and PHB13 (3.0-fold) from the Bα5 sublocus. In particular, PHB3 from Bβ2 and PHB9 from Bβ3 showed strong activation of RCB2-1 of the Bβ1 sublocus by 59-fold. The RCB–PHB interactions were confirmed in the monokaryotic S1–10 strain of L. edodes by showing increased expression of clp1, a downstream gene of the mating signal pathway and the occurrence of clamp connections after the treatment of PHBs. These results indicate that a single PHB can interact with a non-self RCB in a sublocus-specific manner for the activation of the mating pheromone signal pathways in L. edodes.

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What Role Might Non-Mating Receptors Play in Schizophyllum commune?

Journal of Fungi ◽

10.3390/jof7050399 ◽

2021 ◽

Vol 7 (5) ◽

pp. 399

Author(s):

Sophia Wirth ◽

Daniela Freihorst ◽

Katrin Krause ◽

Erika Kothe

Keyword(s):

Mating Type ◽

Developmental Stages ◽

Functional Characterization ◽

Schizophyllum Commune ◽

Growth Direction ◽

Type Locus ◽

Mating Type Locus ◽

High Level ◽

New Evidence

The B mating-type locus of the tetrapolar basidiomycete Schizophyllum commune encodes pheromones and pheromone receptors in multiple allelic specificities. This work adds substantial new evidence into the organization of the B mating-type loci of distantly related S. commune strains showing a high level of synteny in gene order and neighboring genes. Four pheromone receptor-like genes were found in the genome of S. commune with brl1, brl2 and brl3 located at the B mating-type locus, whereas brl4 is located separately. Expression analysis of brl genes in different developmental stages indicates a function in filamentous growth and mating. Based on the extensive sequence analysis and functional characterization of brl-overexpression mutants, a function of Brl1 in mating is proposed, while Brl3, Brl4 and Brl2 (to a lower extent) have a role in vegetative growth, possible determination of growth direction. The brl3 and brl4 overexpression mutants had a dikaryon-like, irregular and feathery phenotype, and they avoided the formation of same-clone colonies on solid medium, which points towards enhanced detection of self-signals. These data are supported by localization of Brl fusion proteins in tips, at septa and in not-yet-fused clamps of a dikaryon, confirming their importance for growth and development in S. commune.

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Transcriptome and Functional Analysis of Mating in the Basidiomycete Schizophyllum commune

Eukaryotic Cell ◽

10.1128/ec.05214-11 ◽

2011 ◽

Vol 11 (5) ◽

pp. 571-589 ◽

Cited By ~ 27

Author(s):

Susann Erdmann ◽

Daniela Freihorst ◽

Marjatta Raudaskoski ◽

Wolfgang Schmidt-Heck ◽

Elke-Martina Jung ◽

...

Keyword(s):

Mating Type ◽

Fluorescent Protein ◽

Expression Patterns ◽

Functional Characterization ◽

Schizophyllum Commune ◽

Northern Hybridization ◽

Cell Periphery ◽

Dependent Manner ◽

Type Locus ◽

Mating Type Locus

ABSTRACTIn this study, we undertook a functional characterization and transcriptome analysis that enabled a comprehensive study of the mating type loci of the mushroomSchizophyllum commune. Induced expression of both thebar2receptor and thebap2(2)pheromone gene within 6 to 12 h after mates' contact was demonstrated by quantitative real-time PCR. Similar temporal expression patterns were confirmed for the allelicbbr1receptor andbbp1pheromone-encoding genes by Northern hybridization. Interestingly, the fusion of clamp connections to the subterminal cell was delayed in mating interactions in which one of the compatible partners expressed thebar2receptor with a truncated C terminus. This developmental delay allowed the visualization of a green fluorescent protein (Gfp)-labeled truncated receptor at the cell periphery, consistent with a localization in the plasma membrane of unfused pseudoclamps. This finding does not support hypotheses envisioning a receptor localization to the nuclear membrane facilitating recognition between the two different nuclei present in each dikaryotic cell. Rather, Gfp fluorescence observed in such pseudoclamps indicated a role of receptor-pheromone interaction in clamp fusion. Transcriptome changes associated with mating interactions were analyzed in order to identify a role for pheromone-receptor interactions. We detected a total of 89 genes that were transcriptionally regulated in a mating type locusA-dependent manner, employing a cutoff of 5-fold changes in transcript abundance. Upregulation in cell cycle-related genes and downregulation of genes involved in metabolism were seen with this set of experiments. In contrast, mating type locusB-dependent transcriptome changes were observed in 208 genes, with a specific impact on genes related to cell wall and membrane metabolism, stress response, and the redox status of the cell.

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

Genetics ◽

10.1093/genetics/148.3.1081 ◽

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.

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