scholarly journals Neurospora crassa Light Signal Transduction Is Affected by ROS

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Tatiana A. Belozerskaya ◽  
Natalia N. Gessler ◽  
Elena P. Isakova ◽  
Yulia I. Deryabina
Keyword(s):  
Neurospora Crassa ◽  
Zinc Fingers ◽  
White Collar ◽  
Photochemical Activity ◽  
Light Signal ◽  
Pas Domain ◽  
Light Responses ◽  
Expression Of Genes ◽  
Heterodimeric Complex ◽  
Light Signals

In the ascomycete fungus Neurospora crassa blue-violet light controls the expression of genes responsible for differentiation of reproductive structures, synthesis of secondary metabolites, and the circadian oscillator activity. A major photoreceptor in Neurospora cells is WCC, a heterodimeric complex formed by the PAS-domain-containing polypeptides WC-1 and WC-2, the products of genes white collar-1 and white collar-2. The photosignal transduction is started by photochemical activity of an excited FAD molecule noncovalently bound by the LOV domain (a specialized variant of the PAS domain). The presence of zinc fingers (the GATA-recognizing sequences) in both WC-1 and WC-2 proteins suggests that they might function as transcription factors. However, a critical analysis of the phototransduction mechanism considers the existence of residual light responses upon absence of WCC or its homologs in fungi. The data presented point at endogenous ROS generated by a photon stimulus as an alternative input to pass on light signals to downstream targets.

White collar proteins: PASsing the light signal in Neurospora crassa

1997 ◽  
Vol 5 (11) ◽  
pp. 458-462 ◽  
Author(s):  
Paola Ballario ◽  
Giuseppe Macino
Keyword(s):  
Neurospora Crassa ◽  
White Collar ◽  
Light Signal

scholarly journals PAS Domain-Mediated WC-1/WC-2 Interaction Is Essential for Maintaining the Steady-State Level of WC-1 and the Function of Both Proteins in Circadian Clock and Light Responses of Neurospora

2002 ◽  
Vol 22 (2) ◽  
pp. 517-524 ◽  
Author(s):  
Ping Cheng ◽  
Yuhong Yang ◽  
Kevin H. Gardner ◽  
Yi Liu
Keyword(s):  
Steady State ◽  
Circadian Clock ◽  
State Level ◽  
White Collar ◽  
Feedback Loops ◽  
Proper Function ◽  
Pas Domain ◽  
Steady State Level ◽  
Light Responses

ABSTRACT In the frq-wc-based circadian feedback loops of Neurospora, two PAS domain-containing transcription factors, WHITE COLLAR-1 (WC-1) and WC-2, form heterodimeric complexes that activate the transcription of frequency (frq). FRQ serves two roles in these feedback loops: repressing its own transcription by interacting with the WC complex and positively upregulating the levels of WC-1 and WC-2 proteins. We report here that the steady-state level of WC-1 protein is independently regulated by both FRQ and WC-2 through different posttranscriptional mechanisms. The WC-1 level is extremely low in wc-2 knockout strains, and this low level of expression is independent of wc-1 transcription and FRQ protein expression. In addition, our data show that the PAS domain of WC-2 mediates the interactions of this protein with both WC-1 and FRQ in vivo. Such interactions are essential for maintaining the steady-state level of WC-1 and the proper function of WC-1 and WC-2 in circadian clock and light responses.

scholarly journals Roles for WHITE COLLAR-1 in Circadian and General Photoperception inNeurospora crassa

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Kwangwon Lee ◽  
Jay C Dunlap ◽  
Jennifer J Loros
Keyword(s):  
Feedback Loop ◽  
White Collar ◽  
Circadian System ◽  
Constant Darkness ◽  
Allelic Series ◽  
Light Responses ◽  
Absolute Requirement ◽  
Heterodimeric Complex ◽  
Multiple Levels ◽  
Inneurospora Crassa

AbstractThe transcription factors WHITE COLLAR-1 (WC-1) and WHITE COLLAR-2 (WC-2) interact to form a heterodimeric complex (WCC) that is essential for most of the light-mediated processes in Neurospora crassa. WCC also plays a distinct non-light-related role as the transcriptional activator in the FREQUENCY (FRQ)/WCC feedback loop that is central to the N. crassa circadian system. Although an activator role was expected for WC-1, unanticipated phenotypes resulting from some wc-1 alleles prompted a closer examination of an allelic series for WC-1 that has uncovered roles for this central regulator in constant darkness and in response to light. We analyzed the phenotypes of five different wc-1 mutants for expression of FRQ and WC-1 in constant darkness and following light induction. While confirming the absolute requirement of WC-1 for light responses, the data suggest multiple levels of control for light-regulated genes.

scholarly journals Physical association of the WC-1 photoreceptor and the histone acetyltransferase NGF-1 is required for blue light signal transduction in Neurospora crassa

2012 ◽  
Vol 23 (19) ◽  
pp. 3863-3872 ◽  
Author(s):  
Andrea Brenna ◽  
Benedetto Grimaldi ◽  
Patrizia Filetici ◽  
Paola Ballario
Keyword(s):  
Signal Transduction ◽  
Neurospora Crassa ◽  
Transcriptional Activation ◽  
Light Signal ◽  
Common Mechanism ◽  
Inducible Promoters ◽  
Lxxll Motif ◽  
Light Stimuli ◽  
Environmental Sensor ◽  
H3 Acetylation

In Neurospora crassa and other filamentous fungi, light-dependent–specific phenomena are regulated by transcription factors WC-1 and WC-2. In addition to its transcriptional activity, WC-1 is able to directly sense light stimuli through a LOV sensor domain. Its location in the nucleus and heterodimerization with WC-2, together with the presence of a zinc-finger DNA-binding domain and an environmental sensor domain, all resemble the functional evolutionary architecture adopted by vertebrate nuclear receptors (NRs). Here we describe a scenario in which WC-1 represents a functional orthologue of NRs and acts through association with the chromatin-modifying coactivator NGF-1, which encodes a homologue of the yeast Gcn5p acetyltransferase. To support this view, we show a direct association between WC-1 and NGF-1 that depends on a WC-1 region containing a conserved functional LXXLL motif, a signature previously described as being an exclusive feature of NR/coactivator interaction. Our data suggest that a WC-1/NGF-1 complex is preassembled in the dark on light-inducible promoters and that, after exposure to light stimulation, NGF-1–associated HAT activity leads to histone H3 acetylation and transcriptional activation. Finally, we provide evidence for a NGF-1–independent acetylated form of WC-1. Overall our data indicate that Neurospora and higher eukaryotes share a common mechanism for the signal transduction of environmental stimuli.

scholarly journals VIB-1 Is Required for Expression of Genes Necessary for Programmed Cell Death in Neurospora crassa

2006 ◽  
Vol 5 (12) ◽  
pp. 2161-2173 ◽  
Author(s):  
Karine Dementhon ◽  
Gopal Iyer ◽  
N. Louise Glass
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Neurospora Crassa ◽  
Filamentous Fungi ◽  
Somatic Growth ◽  
Genetic Differences ◽  
Extracellular Proteases ◽  
Hyphal Fusion ◽  
Expression Of Genes ◽  
Nonself Recognition

ABSTRACT Nonself recognition during somatic growth is an essential and ubiquitous phenomenon in both prokaryotic and eukaryotic species. In filamentous fungi, nonself recognition is also important during vegetative growth. Hyphal fusion between genetically dissimilar individuals results in rejection of heterokaryon formation and in programmed cell death of the fusion compartment. In filamentous fungi, such as Neurospora crassa, nonself recognition and heterokaryon incompatibility (HI) are regulated by genetic differences at het loci. In N. crassa, mutations at the vib-1 locus suppress nonself recognition and HI mediated by genetic differences at het-c/pin-c, mat, and un-24/het-6. vib-1 is a homolog of Saccharomyces cerevisiae NDT80, which is a transcriptional activator of genes during meiosis. For this study, we determined that vib-1 encodes a nuclear protein and showed that VIB-1 localization varies during asexual reproduction and during HI. vib-1 is required for the expression of genes involved in nonself recognition and HI, including pin-c, tol, and het-6; all of these genes encode proteins containing a HET domain. vib-1 is also required for the production of downstream effectors associated with HI, including the production of extracellular proteases upon carbon and nitrogen starvation. Our data support a model in which mechanisms associated with starvation and nonself recognition/HI are interconnected. VIB-1 is a major regulator of responses to nitrogen and carbon starvation and is essential for the expression of genes involved in nonself recognition and death in N. crassa.

Analysis of light signal transduction affecting morphogenesis of perithecia in Neurospora crassa

1997 ◽  
Vol 9 (1) ◽  
pp. 13-22
Author(s):  
Kohji HASUNUMA ◽  
Yasunobu OGURA ◽  
Kazushi ODA ◽  
Naoto YABE
Keyword(s):  
Signal Transduction ◽  
Neurospora Crassa ◽  
Light Signal ◽  
Light Signal Transduction

scholarly journals Dissecting Colony Development of Neurospora crassa Using mRNA Profiling and Comparative Genomics Approaches

2008 ◽  
Vol 7 (9) ◽  
pp. 1549-1564 ◽  
Author(s):  
Takao Kasuga ◽  
N. Louise Glass
Keyword(s):  
Neurospora Crassa ◽  
Transcriptional Profiling ◽  
Fundamental Aspect ◽  
Colony Development ◽  
Published Data ◽  
Middle Section ◽  
Data Set ◽  
Expression Of Genes ◽  
Spatiotemporal Regulation ◽  
Genetic Mechanisms

ABSTRACT Colony development, which includes hyphal extension, branching, anastomosis, and asexual sporulation, is a fundamental aspect of the life cycle of filamentous fungi; genetic mechanisms underlying these phenomena are poorly understood. We conducted transcriptional profiling during colony development of the model filamentous fungus Neurospora crassa, using 70-mer oligonucleotide microarrays. Relative mRNA expression levels were determined for six sections of defined age excised from a 27-h-old N. crassa colony. Functional category analysis showed that the expression of genes involved in cell membrane biosynthesis, polar growth, and cellular signaling was enriched at the periphery of the colony. The relative expression of genes involved in protein synthesis and energy production was enriched in the middle section of the colony, while sections of the colony undergoing asexual development (conidiogenesis) were enriched in expression of genes involved in protein/peptide degradation and unclassified proteins. A cross-examination of the N. crassa data set with a published data set of Aspergillus niger revealed shared patterns in the spatiotemporal regulation of gene orthologs during colony development. At present, less than 50% of genes in N. crassa have functional annotation, which imposes the chief limitation on data analysis. Using an evolutionary approach, we observed that the expression of phylogenetically conserved groups of genes was enriched in the middle section of an N. crassa colony whereas expression of genes unique to euascomycete species and of N. crassa orphan genes was enriched at the colony periphery and in the older, conidiating sections of a fungal colony.

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