• Korean Journal of Microbiology
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• v.49 no.4
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• pp.419-423
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• 2013

Three genes, nsdD, nsdC, and veA are known to be necessary for positive regulating sexual development of Aspergillus nidulans. Since the mutants of those genes hardly form fruiting bodies in heterokaryons constructed by cross between two of them, it is difficult to isolate double mutants. In this work, double mutants of ${\Delta}nsdD$ ${\Delta}veA$ and ${\Delta}nsdD$ ${\Delta}nsdC$ were isolated using the characteristic of the nsdD deletion mutant that it could develop mature cleistothecia in hypoxic and low temperature culture condition. According to the phenotypes of double mutants, the nsdD gene controls the apical growth independently with veA or nsdC. Deletion of veA or nsdC was epistatic to nsdD deletion for pigment production. Conidia formation in submerged culture with lactose as sole carbon source was observed in ${\Delta}nsdD$ ${\Delta}nsdC$ double mutant implicating it to be unique phenotype of nsdC deletion.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.1-7
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• 1994

Several mutants which never underwent to sexual development(NSD) of Aspergillus nidulans were analyzed genetically and physiologically. They were divided into two groups according to their characterisitics of asexual development after release from aeration block. The mutants in first group proceeded asexual development immediately after removal of aeration block, while those in second group did 10 hours or more later. The NSD mutants were separated into 4 complementation groups, nsdA, nsdB, nsdC and nsdD. The nsdA and nsdD genes were linked to AcrA1 on linkage groupⅡ and pabaA1 on linkage group I, respectively. The mutant alleles were all recessive to wild type allele in heterokayon state. The mutants did not developed cleistothecia on any of carbon sources, except NSD208 which developed cleistothecia on lactose.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.246-251
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• 2006

A lot of mutants which cannot initiate sexual development were screened and several loci including nsdA, nsdB, nsdC, and nsdD were identified in homothallic ascomycetes Aspergillus nidulans. The NSD206, which has nsdC6 allele, showed typical phenotype of NSD (Never in sexual development) mutants. The nsdC gene was cloned by transforming NSDP697 ($nsdC^-$, $pryG^-$) with AMA1-NotI genomic library. The transforming library DNA recovered from several transformants showing wild phenotype carried about 10 kb genomic DNA insert. The DNA sequence of nsdC was analysed using GPS (Genome priming system). The nsdC gene has an open reading frame (ORF) of 1,929 bp encoding a putative polypeptide of 643 amino acids. The NsdC carries $C_2H_2C_2H_2C_2HC$ type zinc finger DNA binding domains in the middle of the polypeptide. A coiled-coil domain at its C terminus were also found. In nsdC6 allele, a single T insertion was occurred between 407-408 bp leading to the frameshift mutation and early termination of translation producing the truncated protein which has only 139 amino acids.

• The Korean Journal of Mycology
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• v.18 no.4
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• pp.225-232
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• 1990

In order to find an useful condition under which the mutants defective in sexual development could be isolated, the effects of several cultural conditions on the developments of Aspergillus nidulans were examined. Among several conditions found to restrict the asexual sporulation but enhance the sexual process, the interference of aeration by sealing the plates with sealing film was the most useful one for the purpose of mutant isolation. Sealing at any time before 20 hours from inoculation prevented both sexual and asexual process. When the seal was removed after 24 hours, however, the mycelia developed only to sexual organs. Using this properity, the early morphogenic process of sexual development could be easily observed and a number of mutants that showed some defects in the process could be isolated. The mutants were divided into 3 groups, NSD (never in sexual development), BSD (block in sexual development) and ASD (abnormal in sexual development). NSD mutants never produced either the $H{\ddot{u}}lle$ cells or cleistothecia and some produced the asexual organs even when the aeration was restricted. BSD mutants were blocked in the process of $H{\ddot{u}}lle$ cell, cleistothecia, crozier, asci or ascospore formation. ASD mutants had defects in the amount of cleistothecia, time of cleistothecial maturation or color of ascospores.

• Journal of Microbiology
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• v.41 no.3
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• pp.259-261
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• 2003

The nsdD gene has been predicted to encode a GATA type transcription factor with the type IVb zinc finger DNA binding domain functions in activating sexual development of A. nidulans. In several allelic mutants of nsdD producing truncated NsdD polypeptides lacking the C-terminal zinc finger, the transcription level of nsdD gene was greatly increased. Also in an over-expressed mutant, the transcription under its own promoter was reduced. These results suggest that the expression of nsdD is negatively autoregulated. When the nsdD gene was over-expressed, cleistothecia were formed in excess amounts even in the presence of 0.6 M KC1 that inhibited sexual development of the wild type. Northern blot analysis revealed that the expression of nsdD was repressed by 0.6 M KC1. These results strongly suggest that the inhibition of sexual development by salts was carried out via the nsdD involved regulatory network.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.227.3-227
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• 2005