hex-1, a Gene Unique to Filamentous Fungi, Encodes the Major Protein of the Woronin Body and Functions as a Plug for Septal Pores

Tenney, Karen; Hunt, Ian; Sweigard, James A.; Pounder, June I.; McClain, Chadonna; Bowman, Emma Jean; Bowman, Barry J.

doi:10.1006/fgbi.2000.1230

Cited by 138 publications

(162 citation statements)

References 38 publications

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“…A probe corresponding to the second exon of hex-1 ( Figure 1A, 3Ј probe) reveals two transcripts (T1 and T2), where T1 is the major transcript and T2 the minor transcript ( Figure 1B). Examination of the 5Ј-ends of hex-1 expressed sequence tags (ESTs) confirmed that T1 is the major transcript and defined its 5Ј end (Figure 1; Tenney et al, 2000). An additional EST (a3f07np) mapped upstream of the T1 start site, suggesting that it might be derived from the longer T2 transcript.…”

Section: Structure and Expression Of The Neurospora Crassa Hex-1 Genementioning

confidence: 87%

“…hex-1 expression in yeast produces intraperoxisomal protein assemblies and recombinant HEX-1 spontaneously crystallizes in vitro, suggesting that HEX-1 is a self-assembling structural protein responsible for formation of the crystalline core of the WB (Jedd and Chua, 2000). Consistently, a Neurospora hex-1 mutant is devoid of the refractive core of the WB and mutant hyphae bleed protoplasm through septal pores after cellular damage, defining a function in septal pore sealing (Jedd and Chua, 2000;Tenney et al, 2000). In the plant pathogen Magnaporthe grisea, a hex-1 mutant is also defective in cell damage-induced septal pore sealing (Soundararajan et al, 2004).…”

Section: Introductionmentioning

confidence: 92%

“…The WB is centered on an oval or hexagonal core, which is surrounded by a closely associated unit membrane and these organelles have been observed by electron microscopy in many Euascomycetes, including plant and human pathogens (Markham and Collinge, 1987). The WB was first purified from Neurospora crassa, and this allowed the identification of a key WBassociated protein, HEX-1 (Jedd and Chua, 2000;Tenney et al, 2000), which uses a peroxisome-targeting signal-1 (PTS1) for vesicular localization (Jedd and Chua, 2000). hex-1 expression in yeast produces intraperoxisomal protein assemblies and recombinant HEX-1 spontaneously crystallizes in vitro, suggesting that HEX-1 is a self-assembling structural protein responsible for formation of the crystalline core of the WB (Jedd and Chua, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…Interestingly, hex-1 shares significant sequence and structural homology with the ancient eIF-5a proteins, suggesting that hex-1 evolved after eIF-5a gene duplication in the ancestral Euascomycete (Yuan et al, 2003). Thus, the WB is a specialized peroxisome, which performs an adaptive function in the maintenance of organismal integrity (Jedd and Chua, 2000;Tenney et al, 2000;Yuan et al, 2003;Soundararajan et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Polarized Gene Expression Determines Woronin Body Formation at the Leading Edge of the Fungal Colony

Tey

North

Reyes

et al. 2005

MBoC

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The Woronin body (WB) is a peroxisome-related organelle that is centered on a crystalline core of the HEX-1 protein, which functions to seal septal pores of filamentous ascomycetes in response to cellular damage. Here, we investigate the cellular and genetic control of WB-formation and show that polarized hex-1 gene expression determines WB-biogenesis at the growing hyphal apex. We find that intron splicing is coupled to efficient hex-1 gene expression and strikingly, when the yellow fluorescent protein was expressed from hex-1 regulatory sequences, we observed a fluorescent gradient that was maximal in apical cells. Moreover, endogenous hex-1 transcripts were specifically enriched at the leading edge of the fungal colony, whereas other transcripts accumulated in basal regions. Time-lapse confocal microscopy showed that HEX-1 crystals normally formed in the vicinity of the hyphal apex in large peroxisomes, which matured and were immobilized at the cell periphery as cells underwent septation. When the hex-1 structural gene was expressed from regulatory sequences of an abundant, basally localized transcript, WB-core formation was redetermined to basal regions of the colony, and these strains displayed loss-of-function phenotypes specifically in apical hyphal compartments. These results show that apically localized gene expression is a key determinant of spatially restricted WB-assembly. We suggest that this type of regulation may be widely used to determine cellular activity in apical regions of the fungal hypha.

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Section: Structure and Expression Of The Neurospora Crassa Hex-1 Genementioning

confidence: 87%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polarized Gene Expression Determines Woronin Body Formation at the Leading Edge of the Fungal Colony

Tey

North

Reyes

et al. 2005

MBoC

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“…5b). Woronin bodies are membrane-bound modified peroxisomes found in the cytoplasm of filamentous ascomycete species and which plug the septal pore following catastrophic injury (Jedd & Chua, 2000;Markham & Collinge, 1987;Tenney et al, 2000); previous studies have associated an unknown peroxidase/catalase activity with Woronin bodies (Schliebs et al, 2006;Tenney et al, 2000). In HI, septal plugging is a rapid response during het-c pin-c incompatibility that occurs less than 5 min post-fusion (Glass & Kaneko, 2003).…”

Section: Ros Are Induced During Himentioning

confidence: 99%

Transcriptional profiling and functional analysis of heterokaryon incompatibility in Neurospora crassa reveals that reactive oxygen species, but not metacaspases, are associated with programmed cell death

et al. 2009

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Heterokaryon incompatibility (HI) is a nonself recognition phenomenon occurring in filamentous fungi that is important for limiting resource plundering and restricting viral transfer between strains. Nonself recognition and HI occurs during hyphal fusion between strains that differ at het loci. If two strains undergo hyphal fusion, but differ in allelic specificity at a het locus, the fusion cell is compartmentalized and undergoes a rapid programmed cell death (PCD). Incompatible heterokaryons show a macroscopic phenotype of slow growth and diminished conidiation, and a microscopic phenotype of hyphal compartmentation and cell death. To understand processes associated with HI and PCD, we used whole-genome microarrays for Neurospora crassa to assess transcriptional differences associated with induction of HI mediated by differences in het-c pin-c haplotype. Our data show that HI is a dynamic and transcriptionally active process. The production of reactive oxygen species is implicated in the execution of HI and PCD in N. crassa, as are several genes involved in phosphatidylinositol and calcium signalling pathways. However, genes encoding mammalian homologues of caspases or apoptosis-inducing factor (AIF) are not required for HI or programmed cell death. These data indicate that PCD during HI occurs via a novel and possibly fungal-specific mechanism, making this pathway an attractive drug target for control of fungal infections.

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Woronin Bodies

2004

Encyclopedic Dictionary of Genetics, Genomics and Proteomics

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hex-1, a Gene Unique to Filamentous Fungi, Encodes the Major Protein of the Woronin Body and Functions as a Plug for Septal Pores

Cited by 138 publications

References 38 publications

Polarized Gene Expression Determines Woronin Body Formation at the Leading Edge of the Fungal Colony

Polarized Gene Expression Determines Woronin Body Formation at the Leading Edge of the Fungal Colony

Transcriptional profiling and functional analysis of heterokaryon incompatibility in Neurospora crassa reveals that reactive oxygen species, but not metacaspases, are associated with programmed cell death

Woronin Bodies

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