The Aspergillus nidulans xprG (phoG) gene encodes a putative transcriptional activator involved in the response to nutrient limitation

Katz, Margaret; Gray, Karen-Ann; Cheetham, Brian F.

doi:10.1016/j.fgb.2005.12.001

Cited by 52 publications

(71 citation statements)

References 31 publications

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“…Interestingly, ndt80D mutants that are blocked in pachytene can revert to mitotic growth if nutrients are replenished (Xu et al 1995). These data are consistent with the hypothesis that sensing nutritional signals may be a conserved feature of Ndt80 and its homologs (Katz et al 2006). In addition to the effects on the initiation of protoperithecial development, both vib-1 and fsd-1 mutants showed a significant decrease in numbers of protoperithecia produced per colony, particularly Dvib-1 mutants, suggesting that VIB-1 and FSD-1 are also involved in the development of female reproductive structures (Figure 9).…”

Section: Discussionsupporting

confidence: 82%

“…S. cerevisiae NDT80 forms an outgroup to other NDT80 homologs, but groups more closely with the clade containing NCU09915. Of these homologs, only vib-1 (NCU03725) and an Aspergillus nidulans homolog of vib-1, xprG (Katz et al 2006;ANID_01414;Figure 2), have been characterized. vib-1 mutants suppress HI and display altered conidiation patterns, and, similar to the xprG mutant, vib-1 mutants are deficient in protease secretion under nutrient-limited conditions (Dementhon et al 2006).…”

Section: Resultsmentioning

confidence: 99%

“…Like many other NDT80 homologs, including those in N. crassa, the DNA-binding domain of CaNdt80 is similar to Ndt80, but the rest of the protein is divergent (Wang et al 2006). In A. nidulans, the NDT80 homolog xprG (ANID_01414; Figure 2) controls the production of proteases upon nutrient starvation (Katz et al 2006), similar to vib-1 (Dementhon et al 2006). xprG is regulated by two hexokinases; it is unknown whether these kinases have a regulatory role for other NDT80 homologs (Katz et al 2000;Bernardo et al 2007).…”

Section: Discussionmentioning

confidence: 99%

“…For example, the Neurospora crassa genome contains homologs of S. cerevisiae meiotic regulators such as IME2, RAD17, and two of the CLB genes, yet homologs to IME1, IME4, UME6, and SUM1 are absent (Borkovich et al 2004). Further, even though homologs to meiotic genes are conserved, their functions have diverged (Xiang and Glass 2002;Chen et al 2004;Katz et al 2006;Bayram et al 2009). …”

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confidence: 99%

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Meiotic Regulators Ndt80 and Ime2 Have Different Roles in Saccharomyces and Neurospora

Hutchison

Glass

2010

Genetics

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Meiosis is a highly regulated process in eukaryotic species. The filamentous fungus Neurospora crassa has been shown to be missing homologs of a number of meiotic initiation genes conserved in Saccharomyces cerevisiae, but has three homologs of the well-characterized middle meiotic transcriptional regulator NDT80. In this study, we evaluated the role of all three NDT80 homologs in the formation of female reproductive structures, sexual development, and meiosis. We found that none of the NDT80 homologs were required for meiosis and that even the triple mutant was unaffected. However, strains containing mutations in NCU09915 (fsd-1) were defective in female sexual development and ascospore maturation. vib-1 was a major regulator of protoperithecial development in N. crassa, and double mutants carrying deletions of both vib-1 (NCU03725) and fsd-1 exhibited a synergistic effect on the timing of female reproductive structure (protoperithecia) formation. We further evaluated the role of the N. crassa homolog of IME2, a kinase involved in initiation of meiosis in S. cerevisiae. Strains containing mutations in ime-2 showed unregulated development of protoperithecia. Genetic analysis indicated that mutations in vib-1 were epistatic to ime-2, suggesting that IME-2 may negatively regulate VIB-1 activity. Our data indicate that the IME2/NDT80 pathway is not involved in meiosis in N. crassa, but rather regulates the formation of female reproductive structures.

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Section: Discussionsupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Meiotic Regulators Ndt80 and Ime2 Have Different Roles in Saccharomyces and Neurospora

Hutchison

Glass

2010

Genetics

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“…NDT80 is present in all fungi examined (152), yet it appears to have duplicated, evolved additional functions, and lost its connection to meiosis. For example, in Aspergillus nidulans, the NDT80 homolog (xprG) is not required for meiosis but is required for nutritional responses (79). In Neurospora crassa, several meiotic genes, including IME1, UME6, and SUM1, are absent, yet there are three NDT80 family members.…”

Section: Sum1/ndt80 Switchmentioning

confidence: 99%

The Sum1/Ndt80 Transcriptional Switch and Commitment to Meiosis in Saccharomyces cerevisiae

Winter

2012

Microbiol Mol Biol Rev

105

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SUMMARY Cells encounter numerous signals during the development of an organism that induce division, differentiation, and apoptosis. These signals need to be present for defined intervals in order to induce stable changes in the cellular phenotype. The point after which an inducing signal is no longer needed for completion of a differentiation program can be termed the “commitment point.” Meiotic development in the yeast Saccharomyces cerevisiae (sporulation) provides a model system to study commitment. Similar to differentiation programs in multicellular organisms, the sporulation program in yeast is regulated by a transcriptional cascade that produces early, middle, and late sets of sporulation-specific transcripts. Although critical meiosis-specific events occur as early genes are expressed, commitment does not take place until middle genes are induced. Middle promoters are activated by the Ndt80 transcription factor, which is produced and activated shortly before most middle genes are expressed. In this article, I discuss the connection between Ndt80 and meiotic commitment. A transcriptional regulatory pathway makes NDT80 transcription contingent on the prior expression of early genes. Once Ndt80 is produced, the recombination (pachytene) checkpoint prevents activation of the Ndt80 protein. Upon activation, Ndt80 triggers a positive autoregulatory loop that leads to the induction of genes that promote exit from prophase, the meiotic divisions, and spore formation. The pathway is controlled by multiple feed-forward loops that give switch-like properties to the commitment transition. The conservation of regulatory components of the meiotic commitment pathway and the recently reported ability of Ndt80 to increase replicative life span are discussed.

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Extracellular proteinase formation in carbon starving Aspergillus nidulans cultures – physiological function and regulation

Szilágyi

Kwon

Bakti

et al. 2011

J. Basic Microbiol.

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Extracellular proteinase formation in carbon depleted cultures of the model filamentous fungus Aspergillus nidulans was studied to elucidate its regulation and possible physiological function. As demonstrated by gene deletion, culture optimization, microbial physiological and enzymological experiments, the PrtA and PepJ proteinases of A. nidulans did not appear to play a decisive role in the autolytic decomposition of fungal cells under the conditions we tested. However, carbon starvation induced formation of the proteinases observable in autolytic cultures. Similar to other degradative enzymes, production of proteinase was regulated by FluG-BrlA asexual developmental signaling and modulated by PacC-dependent pH-responsive signaling. Under the same carbon starved culture conditions, alterations of CreA, MeaB or heterotrimeric G protein mediated signaling pathways caused less significant changes in the formation of extracellular proteinases. Taken together, these results indicate that while the accumulation of PrtA and PepJ is tightly coupled to the initiation of autolysis, they are not essential for autolytic cell wall degradation in A. nidulans. Thus, as Aspergillus genomes contain a large group of genes encoding proteinases with versatile physiological functions, selective control of proteinase production in fungal cells is needed for the improved industrial use of fungi.

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The Aspergillus nidulans xprG (phoG) gene encodes a putative transcriptional activator involved in the response to nutrient limitation

Cited by 52 publications

References 31 publications

Meiotic Regulators Ndt80 and Ime2 Have Different Roles in Saccharomyces and Neurospora

Meiotic Regulators Ndt80 and Ime2 Have Different Roles in Saccharomyces and Neurospora

The Sum1/Ndt80 Transcriptional Switch and Commitment to Meiosis in Saccharomyces cerevisiae

Extracellular proteinase formation in carbon starving Aspergillus nidulans cultures – physiological function and regulation

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