scholarly journals The ich1 gene of the mushroom Coprinus cinereus is essential for pileus formation in fruiting

Development ◽  
1998 ◽  
Vol 125 (16) ◽  
pp. 3133-3141 ◽  
Author(s):  
H. Muraguchi ◽  
T. Kamada

The formation of the pileus in homobasidiomycete fungi is essential for sexual reproduction, because the pileus bears the hymenium, a layer of cells that includes the specialised basidia in which nuclear fusion, meiosis and sporulation occur. The developmental mutant ichijiku of Coprinus cinereus fails to develop a differentiated pileus at the apex of the primordial shaft, which is the basal part of the fruit-body primordia and formed in an early stage of fruit-body differentiation. Genetic analysis indicates that this phenotype is caused by a recessive mutation in a single gene (ich1). The ich1 gene was mapped to chromosome XII using restriction fragment length polymorphism markers and the marker chromosome method, and cloned by complementation using a chromosome-XII-specific cosmid library. The ich1 gene encodes a novel protein of 1,353 amino acids. The Ich1 amino-acid sequence contains nuclear targeting signals, suggesting that the Ich1 protein would function in the nucleus. Northern blot analysis indicates that the ich1 gene is specifically expressed in the pileus of the wild-type fruit-body. No ich1 mRNA was detected in the ichijiku mutant, consistent with loss of the promoter region of ich1 in the mutant genome. These data demonstrate that the ich1 gene product is essential for pileus formation.

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1753-1761 ◽  
Author(s):  
Yukio Murata ◽  
Motohiro Fujii ◽  
Miriam E Zolan ◽  
Takashi Kamada

Abstract A homokaryotic strain (5337) in our culture stock of Coprinus cinereus produced fertile fruit bodies after prolonged culture. Microscopic examination revealed that hyphae dedifferentiated from the tissues of one of the fruit bodies, as well as all basidiospore derivatives from the fruit body, exhibited pseudoclamps, whereas vegetative hyphae of 5337, from which the fruit body developed, had no clamp connections. Genetic analysis showed that the formation of pseudoclamps results from a recessive mutation in a gene designated pcc1 (pseudoclamp connection formation), which is distinct from the A and B mating type genes. Cloning and sequencing of the pcc1 gene and cDNA identified an ORF of 1683 bp interrupted by one intron. Database searches revealed that pcc1 encodes an SRY-type HMG protein. The HMG box shared 44, 41, and 29% sequence identities (>80 amino acids) to those of FPR1 of Podospora anserina, MAT-Mc of Schizosaccharomyces pombe, and prf1 of Ustilago maydis, respectively. Northern analysis revealed that the level of pcc1 expression is higher in the dikaryon, in homokaryons in which the A and B mating type developmental sequences are individually activated, than in the homokaryon in which these sequences are not active. Sequencing of the pcc1-1 mutant allele revealed that the mutant carries a nonsense mutation at serine 211, a residue located between the HMG box and the C terminus. Based on these results, possible roles of the pcc1 gene in the sexual development of homobasidiomycetes are discussed.


Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 133-140
Author(s):  
Kazumi Inada ◽  
Yoshinori Morimoto ◽  
Toshihide Arima ◽  
Yukio Murata ◽  
Takashi Kamada

Abstract Sexual development in the mushroom Coprinus cinereus is under the control of the A and B mating-type loci, both of which must be different for a compatible, dikaryotic mycelium to form between two parents. The A genes, encoding proteins with homeodomain motifs, regulate conjugate division of the two nuclei from each mating partner and promote the formation of clamp connections. The latter are hyphal configurations required for the maintenance of the nuclear status in the dikaryotic phase of basidiomycetes. The B genes encode pheromones and pheromone receptors. They regulate the cellular fusions that complete clamp connections during growth, as well as the nuclear migration required for dikaryosis. The AmutBmut strain (326) of C. cinereus, in which both A- and B-regulated pathways are constitutively activated by mutations, produces, without mating, dikaryon-like, fertile hyphae with clamp connections. In this study we isolated and characterized clampless1-1 (clp1-1), a mutation that blocks clamp formation, an essential step in A-regulated sexual development, in the AmutBmut background. A genomic DNA fragment that rescues the clp1-1 mutation was identified by transformations. Sequencing of the genomic DNA, together with RACE experiments, identified an ORF interrupted by one intron, encoding a novel protein of 365 amino acids. The clp1-1 mutant allele carries a deletion of four nucleotides, which is predicted to cause elimination of codon 128 and frameshifts thereafter. The clp1 transcript was normally detected only in the presence of the A protein heterodimer formed when homokaryons with compatible A genes were mated. Forced expression of clp1 by promoter replacements induced clamp development without the need for a compatible A gene combination. These results indicate that expression of clp1 is necessary and sufficient for induction of the A-regulated pathway that leads to clamp development.


Genetics ◽  
1987 ◽  
Vol 116 (4) ◽  
pp. 531-540
Author(s):  
Aileen K W Taguchi ◽  
Elton T Young

ABSTRACT The alcohol dehydrogenase II (ADH2) gene of the yeast, Saccharomyces cerevisiae, is not transcribed during growth on fermentable carbon sources such as glucose. Growth of yeast cells in a medium containing only nonfermentable carbon sources leads to a marked increase or derepression of ADH2 expression. The recessive mutation, adr6-1, leads to an inability to fully derepress ADH2 expression and to an inability to sporulate. The ADR6 gene product appears to act directly or indirectly on ADH2 sequences 3' to or including the presumptive TATAA box. The upstream activating sequence (UAS) located 5' to the TATAA box is not required for the Adr6- phenotype. Here, we describe the isolation of a recombinant plasmid containing the wild-type ADR6 gene. ADR6 codes for a 4.4-kb RNA which is present during growth both on glucose and on nonfermentable carbon sources. Disruption of the ADR6 transcription unit led to viable cells with decreased ADHII activity and an inability to sporulate. This indicates that both phenotypes result from mutations within a single gene and that the adr6-1 allele was representative of mutations at this locus. The ADR6 gene mapped to the left arm of chromosome XVI at a site 18 centimorgans from the centromere.


2014 ◽  
Vol 104 (11) ◽  
pp. 1201-1207 ◽  
Author(s):  
Luca Sella ◽  
Katia Gazzetti ◽  
Carla Castiglioni ◽  
Wilhelm Schäfer ◽  
Francesco Favaron

Fusarium graminearum is a toxigenic fungal pathogen that causes Fusarium head blight (FHB) and crown rot on cereal crops worldwide. This fungus also causes damping-off and crown and root rots at the early stage of crop development in soybean cultivated in North and South America. Several F. graminearum genes were investigated for their contribution to FHB in cereals but no inherent study is reported for the dicotyledonous soybean host. In this study we determined the disease severity on soybean seedlings of five single gene disrupted mutants of F. graminearum, previously characterized in wheat spike infection. Three of these mutants are impaired on a specific function as the production of deoxynivalenol (DON, Δtri5), lipase (ΔFgl1), and xylanase (Δxyl03624), while the remaining two are MAP kinase mutants (ΔFgOS-2, Δgpmk1), which are altered in signaling pathways. The mutants that were reduced in virulence (Δtri5, ΔFgl1, and ΔFgOS-2) or are avirulent (Δgpmk1) on wheat were correspondently less virulent or avirulent in soybean seedlings, as shown by the extension of lesions and seedling lengths. The Δxyl03624 mutant was as virulent as the wild type mirroring the behavior observed in wheat. However, a different ranking of symptom severity occurred in the two hosts: the ΔFgOS-2 mutant, that infects wheat spikelets similarly to Δtri5 and ΔFgl1 mutants, provided much reduced symptoms in soybean. Differently from the other mutants, we observed that the ΔFgOS-2 mutant was several fold more sensitive to the glyceollin phytoalexin suggesting that its reduced virulence may be due to its hypersensitivity to this phytoalexin. In conclusion, lipase and DON seem important for full disease symptom development in soybean seedlings, OS-2 and Gpmk1 MAP kinases are essential for virulence, and OS-2 is involved in conferring resistance to the soybean phytoalexin.


2012 ◽  
Vol 32 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Lu Chen ◽  
Liping Su ◽  
Jianfang Li ◽  
Yanan Zheng ◽  
Beiqin Yu ◽  
...  

Most cases of gastric cancer (GC) are not diagnosed at early stage which can be curable, so it is necessary to identify effective biomarkers for its diagnosis and pre-warning. We have used methylated DNA immunoprecipitation (MeDIP) to identify genes that are frequently methylated in gastric cancer cell lines. Promoter regions hypermethylation of candidate genes were tested by methylation-specific polymerase chain reaction (MSP) in serum samples, including GC (n= 58), gastric precancerous lesions (GPL,n= 46), and normal controls (NC,n= 30). Eighty two hypermethylated genes were acquired by array analysis and 5 genes (BCAS4, CHRM2, FAM5C, PRACandMYLK) were selected as the candidate genes. Three genes (CHRM2, FAM5CandMYLK) were further confirmed to show methylation rates increased with progression from NC to GPL, then to GC. There was obvious decrease in detection ofFAM5CandMYLKhypermethylation, but notCHRM2, from preoperative to postoperative evaluation (P< 0.001). Combined detection of FAM5C and MYLK hypermethylation had a higher sensitivity in GC diagnosis (77.6%,45/58) and pre-warning (30.4%,14/46) than one single gene detection and also had a high specificity of 90%. The combined hypermethylated status ofFAM5CandMYLKcorrelated with tumor size (P< 0.001), tumor invasion depth (P= 0.001) and tumor-node-metastasis (TNM) stage (P= 0.003). HypermethylatedFAM5CandMYLKcan be used as potential biomarkers for diagnosis and pre-warning of GC.


2003 ◽  
Vol 23 (24) ◽  
pp. 9025-9031 ◽  
Author(s):  
Masahito Shimojo ◽  
Louis B. Hersh

ABSTRACT The transcriptional repressor REST/NRSF (RE-1 silencing transcription factor/neuron-restrictive silencer factor) and the transcriptional regulator REST4 share an N-terminal zinc finger domain structure involved in nuclear targeting. Using this domain as bait in a yeast two-hybrid screen, a novel protein that contains three LIM domains, putative nuclear localization sequences, protein kinase A phosphorylation sites, and a CAAX prenylation motif was isolated. This protein, which is localized around the nucleus, is involved in determining the nuclear localization of REST4 and REST/NRSF. We propose the name RILP, for REST/NRSF-interacting LIM domain protein, to label this novel protein. RILP appears to serve as a nuclear receptor for REST/NRSF, REST4, and possibly other transcription factors.


1994 ◽  
Vol 5 (1) ◽  
pp. 57-70 ◽  
Author(s):  
B H Gibbons ◽  
D J Asai ◽  
W J Tang ◽  
T S Hays ◽  
I R Gibbons

Transcripts approximately 14.5 kilobases in length from 14 different genes that encode for dynein heavy chains have been identified in poly(A)+ RNA from sea urchin embryos. Analysis of the changes in level of these dynein transcripts in response to deciliation, together with their sequence relatedness, suggests that 11 or more of these genes encode dynein isoforms that participate in regeneration of external cilia on the embryo, whereas the single gene whose deduced sequence closely resembles that of cytoplasmic dynein in other organisms appears not to be involved in this regeneration. The four consensus motifs for phosphate binding found previously in the beta heavy chain of sea urchin dynein are present in all five additional isoforms for which extended sequences have been obtained, suggesting that these sites play a significant role in dynein function. Sequence analysis of a approximately 400 amino acid region encompassing the putative hydrolytic ATP-binding site shows that the dynein genes fall into at least six distinct classes. Most of these classes in sea urchin have a high degree of sequence identity with one of the dynein heavy chain genes identified in Drosophila, indicating that the radiation of the dynein gene family into the present classes occurred at an early stage in the evolution of eukaryotes. Evolutionary changes in cytoplasmic dynein have been more constrained than those in the axonemal dyneins.


1976 ◽  
Vol 54 (12) ◽  
pp. 1306-1315 ◽  
Author(s):  
Hans E. Gruen

Flammulina velutipes fruit bodies were grown on partly decayed Populus tremuloides sawdust supplemented with wheat bran and malt extract. In each culture there was a gradation in fruit body size, which served to select test specimens at an early stage of growth. Diffusates collected in agar blocks were applied on the apex of decapitated stipes. Plain agar and dilute potato dextrose agar (PDA/2) alone had the same slight effect on growth. Lamellae placed on plain agar caused limited growth promotion. Lamellae on PDA/2 gave 100–150% more growth promotion than on plain agar during early development, but the activity decreased to zero during the middle of the stage of rapid elongation. Lamellae of that age had no effect on young stipes and the older stipes were insensitive to diffusate from young lamellae. Very small amounts of lamellae promoted stipe elongation. Potato extract alone did not stimulate production of the lamellar diffusate and glucose was less effective than the two nutrients combined. A delay of 2 h in applying lamellar diffusate reduced stipe elongation, and there was no response after 12 h delay. Pilear trama did not produce growth-promoting diffusate.


1980 ◽  
Vol 11 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Kauri Mikkola

AbstractThe melanism of Oligia strigilis (L.) occurs in Finland as geugraphical isolates, whereas that of O. latruncula (D. & Sch.) has a continuous distribution. The local populations of O. strigilis differ from each other in the colouration of the melanic moths and in the relationship between the numerical ratio of the colour forms and stage of air pollution. It appears that melanism has arisen independently in several localities, since diffuse gene flow between localities or from outside Finland seems improbable. According to this mosaic distribution and since the oldest melanic moths known from Finland date from 1961, an early stage of industrial melanism might be in evidence. - Two pairings showed that melanic colouration is a dominant character which seems to be controlled by a single gene pair. The role played by multiple allelism and/or incompleteness of the dominance in the variation of the external appearance of the melanics needs further investigation.


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