acon-3, the Neurospora crassa ortholog of the developmental modifier, medA, complements the conidiation defect of the Aspergillus nidulans mutant

Chung, Dawoon; Greenwald, Charles; Upadhyay, Srijana; Ding, Shengli; Wilkinson, Heather H.; Ebbole, Daniel J.; Shaw, Brian D.

doi:10.1016/j.fgb.2010.12.008

Cited by 21 publications

(23 citation statements)

References 32 publications

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“…Green fluorescent protein (GFP) was visualized using the filter FL filter set 38 HE EGFP (Carl Zeiss Microscopy). Samples were prepared and microscopic observation was performed as previously described (39).…”

Section: Strains and Mediamentioning

confidence: 99%

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Laccases Involved in 1,8-Dihydroxynaphthalene Melanin Biosynthesis in Aspergillus fumigatus Are Regulated by Developmental Factors and Copper Homeostasis

2013

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Aspergillus fumigatus produces heavily melanized infectious conidia. The conidial melanin is associated with fungal virulence and resistance to various environmental stresses. This 1,8-dihydroxynaphthalene (DHN) melanin is synthesized by enzymes encoded in a gene cluster in A. fumigatus, including two laccases, Abr1 and Abr2. Although this gene cluster is not conserved in all aspergilli, laccases are critical for melanization in all species examined. Here we show that the expression of A. fumigatus laccases Abr1/2 is upregulated upon hyphal competency and drastically increased during conidiation. The Abr1 protein is localized at the surface of stalks and conidiophores, but not in young hyphae, consistent with the gene expression pattern and its predicted role. The induction of Abr1/2 upon hyphal competency is controlled by BrlA, the master regulator of conidiophore development, and is responsive to the copper level in the medium. We identified a developmentally regulated putative copper transporter, CtpA, and found that CtpA is critical for conidial melanization under copper-limiting conditions. Accordingly, disruption of CtpA enhanced the induction of abr1 and abr2, a response similar to that induced by copper starvation. Furthermore, nonpigmented ctpA⌬ conidia elicited much stronger immune responses from the infected invertebrate host Galleria mellonella than the pigmented ctpA⌬ or wild-type conidia. Such enhancement in eliciting Galleria immune responses was independent of the ctpA⌬ conidial viability, as previously observed for the DHN melanin mutants. Taken together, our findings indicate that both copper homeostasis and developmental regulators control melanin biosynthesis, which affects conidial surface properties that shape the interaction between this pathogen and its host.A spergillus fumigatus is an opportunistic pathogen that causes life-threatening invasive disease in immunocompromised hosts (1). Its asexual spores, named conidia, are the initial source of inocula for infection and are the vehicles for dispersal and survival. Under favorable conditions, conidia break dormancy and grow as elongated, highly polarized hyaline hyphae. Upon achieving competency and exposure to air, hyphae produce aerial conidiophore stalks and develop elaborate multicellular conidiophores that generate chains of melanized uninucleate conidia (2, 3) (Fig. 1A and B). BrlA, a C 2 H 2 zinc finger transcription factor, is the master regulator that controls the initiation of conidiophore development in Aspergillus (4, 5). AbaA and WetA, two other important regulators that function downstream of BrlA, are required for proper progression of conidiation (6). The abaA gene is activated during the middle stage of conidiophore development, while the wetA gene is required for the activation of late conidiation-specific genes.The 1,8-dihydroxynaphthalene (DHN) melanin coating A. fumigatus conidia gives them their characteristic bluish green color (Fig. 1B). Melanin is an amorphous polymer that is produced by a variety of microbes and ...

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Section: Strains and Mediamentioning

confidence: 99%

“…For gene expression studies, experiments were conducted and samples were collected as previously described (39). The wild-type strain and the ctpA⌬ mutant were grown in 100 ml of complete liquid medium with 1.2 M sorbitol at 30°C with or without the addition of BCS or CuSO 4 .…”

Section: Strains and Mediamentioning

confidence: 99%

Laccases Involved in 1,8-Dihydroxynaphthalene Melanin Biosynthesis in Aspergillus fumigatus Are Regulated by Developmental Factors and Copper Homeostasis

2013

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“…Unlike acon-2, acon-3 or fl, whose mutants displayed complete failure at certain developmental steps in conidiation (Springer and Yanofsky, 1989;Bailey and Ebbole, 1998;Greenwald et al, 2010;Chung et al, 2011), the vad-5 deletion mutant could still produce mature conidia although the degree of conidial production was greatly reduced. Thus, vad-5 might not function as a key regulatory gene governing the switch from vegetative growth to conidiation but, instead influences conidiation by controlling many genes that contribute to conidiation.…”

Section: Discussionmentioning

confidence: 99%

“…crassa has long been used as a model system in studying the regulatory mechanisms of conidiation (Matsuyama et al, 1974;Selitrennikoff et al, 1974;Springer and Yanofsky, 1989;Springer, 1993;Bailey and Ebbole, 1998;Bailey-Shrode and Ebbole, 2004;Banno et al, 2005;Greenwald et al, 2010;Chung et al, 2011). Its genome was sequenced and gene deletion mutants are available from the Fungal Genetics Stock Center for about 70% of the proteinencoding genes in its genome.…”

Section: Introductionmentioning

confidence: 99%

“…Conidiation in N. crassa is also regulated by acon-3 (NCU07617), which is required to form major constriction chains (Springer and Yanofsky, 1989). The gene acon-3 could complement developmental defects in A. nidulans caused by deletion of its homologous gene medA (Chung et al, 2011). Although the medA protein has unknown transcription factor domain, MedA has regulatory function in gene expression (Busby et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the role of transcription factor VAD-5 in conidiation of Neurospora crassa

Sun

et al. 2012

Fungal Genetics and Biology

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The transcription factor FgMed1 is involved in early conidiogenesis and DON biosynthesis in the plant pathogenic fungus Fusarium graminearum

Fan

Zhang

et al. 2019

Appl Microbiol Biotechnol

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acon-3, the Neurospora crassa ortholog of the developmental modifier, medA, complements the conidiation defect of the Aspergillus nidulans mutant

Cited by 21 publications

References 32 publications

Laccases Involved in 1,8-Dihydroxynaphthalene Melanin Biosynthesis in Aspergillus fumigatus Are Regulated by Developmental Factors and Copper Homeostasis

Laccases Involved in 1,8-Dihydroxynaphthalene Melanin Biosynthesis in Aspergillus fumigatus Are Regulated by Developmental Factors and Copper Homeostasis

Analysis of the role of transcription factor VAD-5 in conidiation of Neurospora crassa

The transcription factor FgMed1 is involved in early conidiogenesis and DON biosynthesis in the plant pathogenic fungus Fusarium graminearum

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