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Conidiation in Neurospora crassa: vegetative reproduction by a model fungus. Int Microbiol 2019; 23:97-105. [DOI: 10.1007/s10123-019-00085-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/14/2019] [Accepted: 05/20/2019] [Indexed: 12/13/2022]
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Pengkit A, Jeon SS, Son SJ, Shin JH, Baik KY, Choi EH, Park G. Identification and functional analysis of endogenous nitric oxide in a filamentous fungus. Sci Rep 2016; 6:30037. [PMID: 27425220 PMCID: PMC4948021 DOI: 10.1038/srep30037] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/29/2016] [Indexed: 12/28/2022] Open
Abstract
In spite of its prevalence in animals and plants, endogenous nitric oxide (NO) has been rarely reported in fungi. We present here our observations on production of intracellular NO and its possible roles during development of Neurospora crassa, a model filamentous fungus. Intracellular NO was detected in hypha 8–16 hours after incubation in Vogel’s minimal liquid media and conidiophores during conidiation using a fluorescent indicator (DAF-FM diacetate). Treatment with cPTIO, an NO scavenger, significantly reduced fluorescence levels and hindered hyphal growth in liquid media and conidiation, whereas exogenous NO enhanced hyphal extension on VM agar media and conidia formation. NO scavenging also dramatically diminished transcription of con-10 and con-13, genes preferentially expressed during conidiation. Our results suggest that intracellular NO is generated in young hypha growing in submerged culture and during conidia development and regulate mycelial development and conidia formation.
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Affiliation(s)
- Anchalee Pengkit
- Plasma Bioscience Research Center, Kwangwoon University, Seoul, 01897, Republic of Korea
| | - Seong Sil Jeon
- Department of Electrical and Biological Physics, Kwangwoon University, Seoul, 01897, Republic of Korea
| | - Soo Ji Son
- Department of Chemistry, Kwangwoon University, Seoul, 01897, Republic of Korea
| | - Jae Ho Shin
- Department of Chemistry, Kwangwoon University, Seoul, 01897, Republic of Korea
| | - Ku Yeon Baik
- Plasma Bioscience Research Center, Kwangwoon University, Seoul, 01897, Republic of Korea.,Department of Electrical and Biological Physics, Kwangwoon University, Seoul, 01897, Republic of Korea
| | - Eun Ha Choi
- Plasma Bioscience Research Center, Kwangwoon University, Seoul, 01897, Republic of Korea.,Department of Electrical and Biological Physics, Kwangwoon University, Seoul, 01897, Republic of Korea
| | - Gyungsoon Park
- Plasma Bioscience Research Center, Kwangwoon University, Seoul, 01897, Republic of Korea.,Department of Electrical and Biological Physics, Kwangwoon University, Seoul, 01897, Republic of Korea
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Suzuki S, Sarikaya Bayram Ö, Bayram Ö, Braus GH. conF and conJ contribute to conidia germination and stress response in the filamentous fungus Aspergillus nidulans. Fungal Genet Biol 2013; 56:42-53. [PMID: 23644150 DOI: 10.1016/j.fgb.2013.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 04/08/2013] [Accepted: 04/10/2013] [Indexed: 01/08/2023]
Abstract
Light induces various responses in fungi including formation of asexual and sexual reproductive structures. The formation of conidia in the filamentous fungus Aspergillus nidulans is regulated by red and blue light receptors. Expression of conidia associated con genes, which are widely spread in the fungal kingdom, increases upon exposure to light. We have characterized the light-inducible conF and conJ genes of A. nidulans which are homologs of con-6 and con-10 of Neurospora crassa. con genes are expressed during conidia formation in asexual development. Five minutes light exposure are sufficient to induce conF or conJ expression in vegetative mycelia. Similar to N. crassa there were no significant phenotypes of single con mutations. A double conF and conJ deletion resulted in significantly increased cellular amounts of glycerol or erythritol. This leads to a delayed germination phenotype combined with increased resistance against desiccation. These defects were rescued by complementation of the double mutant strain with either conF or conJ. This suggests that fungal con genes exhibit redundant functions in controlling conidia germination and adjusting cellular levels of substances which protect conidia against dryness.
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Affiliation(s)
- Satoshi Suzuki
- Institute of Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg August University, Grisebachstr. 8, 37077 Göttingen, Germany
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Olmedo M, Ruger-Herreros C, Luque EM, Corrochano LM. A complex photoreceptor system mediates the regulation by light of the conidiation genes con-10 and con-6 in Neurospora crassa. Fungal Genet Biol 2009; 47:352-63. [PMID: 19932184 DOI: 10.1016/j.fgb.2009.11.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 11/13/2009] [Indexed: 11/24/2022]
Abstract
Genes con-10 and con-6 in Neurospora crassa are activated during conidiation or after illumination of vegetative mycelia. Light activation requires the white-collar complex (WCC), a transcription factor complex composed of the photoreceptor WC-1 and its partner WC-2. We have characterized the photoactivation of con-10 and con-6, and we have identified 300bp required for photoactivation in the con-10 promoter. A complex stimulus-response relationship for con-10 and con-6 photoactivation suggested the activity of a complex photoreceptor system. The WCC is the key element for con-10 activation by light, but we suggest that other photoreceptors, the cryptochrome CRY-1, the rhodopsin NOP-1, and the phytochrome PHY-2, modify the activity of the WCC for con-10 photoactivation, presumably through a repressor. In addition we show that the regulatory protein VE-1 is required for full photocarotenogenesis. We propose that these proteins may modulate the WCC in a gene-specific way.
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Affiliation(s)
- María Olmedo
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, E-41080 Sevilla, Spain
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A genetic selection for Neurospora crassa mutants altered in their light regulation of transcription. Genetics 2008; 178:171-83. [PMID: 18202366 DOI: 10.1534/genetics.107.079582] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Transcription of the Neurospora crassa gene con-10 is induced during conidiation and following exposure of vegetative mycelia to light, but light activation is transient due to photoadaptation. We describe mutational analyses of photoadaptation using a N. crassa strain bearing a translational fusion of con-10, including its regulatory region, to a selectable bacterial gene conferring hygromycin resistance (hph). Growth of this strain was sensitive to hygromycin, upon continuous culture in the light. Five mutants were isolated that were resistant to hygromycin when cultured under constant light. Three mutant strains displayed elevated, sustained accumulation of con-10::hph mRNA during continued light exposure, suggesting that they bear mutations that reduce or eliminate the presumed light-dependent repression mechanism that blocks con-10 transcription upon prolonged illumination. These mutations altered photoadaptation for only a specific group of genes (con-10 and con-6), suggesting that regulation of photoadaptation is relatively gene specific. The mutations increased light-dependent mRNA accumulation for genes al-1, al-2, and al-3, each required for carotenoid biosynthesis, resulting in a threefold increase in carotenoid accumulation following continuous light exposure. Identification of the altered gene or genes in these mutants may reveal novel proteins that participate in light regulation of gene transcription in fungi.
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Bailey-Shrode L, Ebbole DJ. The fluffy gene of Neurospora crassa is necessary and sufficient to induce conidiophore development. Genetics 2005; 166:1741-9. [PMID: 15126394 PMCID: PMC1470807 DOI: 10.1534/genetics.166.4.1741] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The fl (fluffy) gene of Neurospora crassa encodes a binuclear zinc cluster protein that regulates the production of asexual spores called macroconidia. Two other genes, acon-2 and acon-3, play major roles in controlling development. fl is induced specifically in differentiating tissue during conidiation and acon-2 plays a role in this induction. We examined the function of fl by manipulating its level of expression in wild-type and developmental mutant strains. Increasing expression of fl from a heterologous promoter in a wild-type genetic background is sufficient to induce conidiophore development. Elevated expression of fl leads to induction of development of the acon-2 mutant in nitrogen-starved cultures, but does not bypass the conidiation defect of the acon-3 mutant. These findings indicate that fl acts downstream of acon-2 and upstream of acon-3 in regulating gene expression during development. The eas, con-6, and con-10 genes are induced at different times during development. Morphological changes induced by artificially elevated fl expression in the absence of environmental cues were correlated with increased expression of eas, but not con-6 or con-10. Thus, although inappropriate expression of fl in vegetative hyphae is sufficient to induce conidial morphogenesis, complete reconstitution of development leading to the formation of mature conidia may require environmental signals to regulate fl activity and/or appropriate induction of fl expression in the developing conidiophore.
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Affiliation(s)
- Lori Bailey-Shrode
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843-2132, USA
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Bailey-Shrode L, Ebbole DJ. The fluffy Gene of Neurospora crassa Is Necessary and Sufficient to Induce Conidiophore Development. Genetics 2004. [DOI: 10.1093/genetics/166.4.1741] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
The fl (fluffy) gene of Neurospora crassa encodes a binuclear zinc cluster protein that regulates the production of asexual spores called macroconidia. Two other genes, acon-2 and acon-3, play major roles in controlling development. fl is induced specifically in differentiating tissue during conidiation and acon-2 plays a role in this induction. We examined the function of fl by manipulating its level of expression in wild-type and developmental mutant strains. Increasing expression of fl from a heterologous promoter in a wild-type genetic background is sufficient to induce conidiophore development. Elevated expression of fl leads to induction of development of the acon-2 mutant in nitrogen-starved cultures, but does not bypass the conidiation defect of the acon-3 mutant. These findings indicate that fl acts downstream of acon-2 and upstream of acon-3 in regulating gene expression during development. The eas, con-6, and con-10 genes are induced at different times during development. Morphological changes induced by artificially elevated fl expression in the absence of environmental cues were correlated with increased expression of eas, but not con-6 or con-10. Thus, although inappropriate expression of fl in vegetative hyphae is sufficient to induce conidial morphogenesis, complete reconstitution of development leading to the formation of mature conidia may require environmental signals to regulate fl activity and/or appropriate induction of fl expression in the developing conidiophore.
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Affiliation(s)
- Lori Bailey-Shrode
- Program for the Biology of Filamentous Fungi, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843-2132
| | - Daniel J Ebbole
- Program for the Biology of Filamentous Fungi, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843-2132
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Ebbole DJ. Carbon catabolite repression of gene expression and conidiation in Neurospora crassa. Fungal Genet Biol 1998; 25:15-21. [PMID: 9806802 DOI: 10.1006/fgbi.1998.1088] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- D J Ebbole
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, 77843-2132, USA.
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Lee K, Ebbole DJ. Analysis of two transcription activation elements in the promoter of the developmentally regulated con-10 gene of Neurospora crassa. Fungal Genet Biol 1998; 23:259-68. [PMID: 9680956 DOI: 10.1006/fgbi.1998.1043] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The con-10 gene of Neurospora crassa is activated during conidiation. CRS-B (conidiation response sequence-B) and CGE (con-10 general enhancer) elements have been proposed to function as sites of transcriptional activation and as possible elements that confer developmental regulation to con-10. In a specific analysis of the roles of these elements we found that two CRS-B elements are necessary for full activation of con-10 during macroconidiation, whereas two CGE elements are functionally redundant, such that a single CGE is sufficient for maximal expression. However, CRS-B and CGE elements are not sufficient for developmental activation of a reporter gene. The CRS-B element was further dissected and one of the CRS-B elements appears to function in repression as well as activation. con-10 is also highly expressed during microconidiation, a different form of asexual sporulation, but we show here that CRS-B elements do not play a significant role in con-10 expression during microconidiation. Both CRS-B elements contribute to basal con-10 expression during mycelial growth. con-10 is also regulated by light, and CRS-B and CGE elements may play minor roles in controlling con-10 expression in response to light.
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Affiliation(s)
- K Lee
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, USA
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Lauter FR, Yamashiro CT, Yanofsky C. Light stimulation of conidiation in Neurospora crassa: Studies with the wild-type strain and mutants wc-1, wc-2 and acon-2. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1997. [DOI: 10.1016/s1011-1344(96)07405-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Yamashiro CT, Ebbole DJ, Lee BU, Brown RE, Bourland C, Madi L, Yanofsky C. Characterization of rco-1 of Neurospora crassa, a pleiotropic gene affecting growth and development that encodes a homolog of Tup1 of Saccharomyces cerevisiae. Mol Cell Biol 1996; 16:6218-28. [PMID: 8887652 PMCID: PMC231625 DOI: 10.1128/mcb.16.11.6218] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The filamentous fungus Neurospora crassa undergoes a well-defined developmental program, conidiation, that culminates in the production of numerous asexual spores, conidia. Several cloned genes, including con-10, are expressed during conidiation but not during mycelial growth. Using a previously described selection strategy, we isolated mutants that express con-10 during mycelial growth. Selection was based on expression of an integrated DNA fragment containing the con-10 promoter-regulatory region followed by the initial segment of the con-10 open reading frame fused in frame with the bacterial hygromycin B phosphotransferase structural gene (con10'-'hph). Resistance to hygromycin results from mutational alterations that allow mycelial expression of the con-10'-'hph gene fusion. A set of drug-resistant mutants were isolated; several of these had abnormal conidiation phenotypes and were trans-acting, i.e., they allowed mycelial expression of the endogenous con-10 gene. Four of these had alterations at a single locus, designated rco-1 (regulation of conidiation). Strains with the rco-1 mutant alleles were aconidial, female sterile, had reduced growth rates, and formed hyphae that coiled in a counterclockwise direction, opposite that of the wild type. The four rco-1 mutants had distinct conidiation morphologies, suggesting that conidiation was blocked at different stages. Wild-type rco-1 was cloned by a novel procedure employing heterokaryon-assisted transformation and ligation-mediated PCR. The predicted RCO1 polypeptide is a homolog of Tup1 of Saccharomyces cerevisiae, a multidomain protein that mediates transcriptional repression of genes concerned with a variety of processes. Like tup1 mutants, null mutants of rco-1 are viable and pleiotropic. A promoter element was identified that could be responsible for RCO1-mediated vegetative repression of con-10 and other conidiation genes.
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Affiliation(s)
- C T Yamashiro
- Department of Biological Sciences, Stanford University, California 94305-5020, USA
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Dearnaley J, Maleszka J, Hardham A. Synthesis of zoospore peripheral vesicles during sporulation of Phytophthora cinnamomi. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0953-7562(96)80098-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Madi L, Ebbole DJ, White BT, Yanofsky C. Mutants of Neurospora crassa that alter gene expression and conidia development. Proc Natl Acad Sci U S A 1994; 91:6226-30. [PMID: 8016143 PMCID: PMC44171 DOI: 10.1073/pnas.91.13.6226] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Several genes have been identified that are highly expressed during conidiation. Inactivation of these genes has no observable phenotypic effect. Transcripts of two such genes, con-6 and con-10, are normally absent from vegetative mycelia. To identify regulatory genes that affect con-6 and/or con-10 expression, strains were prepared in which the regulatory regions for these genes were fused to a gene conferring hygromycin resistance. Mutants were then selected that were resistant to the drug during mycelial growth. Mutations in several of the isolates had trans effects; they activated transcription of the corresponding intact gene and, in most isolates, one or more of the other con genes. Most interestingly, resistant mutants were obtained that were defective at different stages of conidiation. One mutant conidiated under conditions that do not permit conidiation in wild type.
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MESH Headings
- Cinnamates
- Crosses, Genetic
- Drug Resistance, Microbial/genetics
- Gene Expression Regulation, Fungal/radiation effects
- Genes, Fungal
- Genes, Regulator
- Hygromycin B/analogs & derivatives
- Hygromycin B/toxicity
- Mutagenesis
- Neurospora crassa/genetics
- Neurospora crassa/growth & development
- Neurospora crassa/radiation effects
- RNA, Fungal/biosynthesis
- RNA, Fungal/isolation & purification
- RNA, Messenger/biosynthesis
- RNA, Messenger/isolation & purification
- Regulatory Sequences, Nucleic Acid
- Species Specificity
- Spores, Fungal/genetics
- Spores, Fungal/physiology
- Spores, Fungal/radiation effects
- Transcription, Genetic
- Ultraviolet Rays
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Affiliation(s)
- L Madi
- Department of Plant Pathology and Microbiology, Texas A&M University 77843
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Lauter FR, Yanofsky C. Day/night and circadian rhythm control of con gene expression in Neurospora. Proc Natl Acad Sci U S A 1993; 90:8249-53. [PMID: 8367490 PMCID: PMC47326 DOI: 10.1073/pnas.90.17.8249] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In the filamentous fungus Neurospora crassa, several events in the process of conidiation are influenced by light. Two genes, con-6 and con-10, which were previously shown to be transcriptionally activated during conidiation and by exposure to light, were found to be unexpressed in mycelium maintained in constant darkness or in constant light. However, when mycelium was shifted from darkness to light, transcripts of both genes appeared and were abundant. Upon further illumination both transcripts disappeared--i.e., their continued production was light repressed. When dark-grown mycelium was exposed to a light pulse and reincubated in the dark, expression of con-6 and con-10 exhibited a 20-hr circadian periodicity. Both genes were photoinducible throughout the stages of the circadian cycle. In the mutant strains bd and bd;frq9, con-6 and con-10 were light inducible but were not normally light repressible. Mutant genes such as acon-2, acon-3, and fl that block developmental expression of con-6 and/or con-10 did not prevent their photoinduction.
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Affiliation(s)
- F R Lauter
- Department of Biological Sciences, Stanford University, CA 94305
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Springer ML. Genetic control of fungal differentiation: the three sporulation pathways of Neurospora crassa. Bioessays 1993; 15:365-74. [PMID: 8357339 DOI: 10.1002/bies.950150602] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Sporulation in the mold Neurospora crassa can proceed along three very different pathways, leading to the production of three types of spores. Two asexual sporulation pathways that lead to the formation of macroconidia and microconidia involve budding from hyphae by two different mechanisms. A much more complex sexual reproductive pathway involves the formation of a fruiting body called a perithecium, in which meiosis takes place and ascospores are formed in sac-like cells called asci. Numerous mutations exist that affect these developmental pathways and genes have been isolated that are expressed preferentially during sporulation. The Neurospora sporulation pathways offer a simple system with which to study mechanisms and regulation of development that are usually obscured by complex cell-cell interactions involved in animal and plant development.
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Affiliation(s)
- M L Springer
- Department of Biochemistry, Stanford University School of Medicine, CA 94305
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Springer ML, Yanofsky C. Expression of con genes along the three sporulation pathways of Neurospora crassa. Genes Dev 1992; 6:1052-7. [PMID: 1534304 DOI: 10.1101/gad.6.6.1052] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The filamentous fungus Neurospora crassa produces three types of spores by using different developmental pathways: macroconidiation, microconidiation, and sexual spore (ascospore) formation. Several genes of unknown function have been cloned by virtue of their expression during macroconidiation but not during mycelial growth (con genes). It had been postulated that expression of the con genes was specific to macroconidiation. To test this assumption, protein extracts from macroconidia, microconidia, ascospores, and protoperithecia (sexual structures) were analyzed for the product of one of the con genes, con-10, by immunoblotting using a CON10-specific antiserum. CON10 was detected in all of these extracts. An immunologically related protein was detected in an extract from ascospores of a nonconidiating Neurospora species, N. africana. Total RNA isolated from the three types of N. crassa spores was analyzed for con gene mRNA by Northern blotting using five different con genes as probes. Transcripts for four of the genes were detected in all three spore types; mRNA for the fifth gene was detected in macroconidia and microconidia but not in ascospores. Analysis of aconidial and female sterile mutants showed that expression of the con genes along any one developmental pathway occurs when expression along another pathway is genetically blocked.
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Affiliation(s)
- M L Springer
- Department of Biological Sciences, Stanford University, California 94305
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