The CHY-type zinc finger protein FgChy1 regulates polarized growth, pathogenicity, and microtubule assembly in Fusarium graminearum

Microtubules, as transport tracks, play important roles in hyphal tip growth in filamentous fungi, but microtubule-associated proteins involved in polarized growth remain unknown. Here, we found that one novel zinc finger protein, FgChy1, is required for microtubule morphology and polarized growth in Fusarium graminearum. The Fgchy1 mutant presented curved and directionless growth of hyphae. Importantly, the conidia and germ tubes of the Fgchy1 mutant exhibited badly damaged and less organized beta-tubulin cytoskeletons. Compared with the wild type, the Fgchy1 mutant lost the ability to maintain polarity and was also more sensitive to the anti-microtubule drugs carbendazim and nocodazole, likely due to the impaired microtubule cytoskeleton. Indeed, the hyphae of the wild type treated with nocodazole exhibited a morphology consistent with that of the Fgchy1 mutant. Interestingly, the disruption of FgChy1 resulted in the off-center localization of actin patches and the polarity-related polarisome protein FgSpa2 from the hyphal tip axis. A similar defect in FgSpa2 localization was also observed in the nocodazole-treated wild-type strain. In addition, FgChy1 is also required for conidiogenesis, septation, sexual reproduction, pathogenicity and deoxynivalenol production. Overall, this study provides the first demonstrations of the functions of the novel zinc finger protein FgChy1 in polarized growth, development and virulence in filamentous fungi.

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Disruption of a Locus Encoding a Nucleolar Zinc Finger Protein Decreases Tachyzoite-to-Bradyzoite Differentiation in Toxoplasma gondii

Infection and Immunity ◽

10.1128/iai.73.10.6680-6688.2005 ◽

2005 ◽

Vol 73 (10) ◽

pp. 6680-6688 ◽

Cited By ~ 26

Author(s):

Padmini Vanchinathan ◽

Jeremy L. Brewer ◽

Omar S. Harb ◽

John C. Boothroyd ◽

Upinder Singh

Keyword(s):

Toxoplasma Gondii ◽

Zinc Finger ◽

Insertional Mutagenesis ◽

Zinc Finger Protein ◽

Chemical Mutagenesis ◽

Selection Strategy ◽

Wild Type ◽

Altered Expression ◽

Finger Protein ◽

Bradyzoite Differentiation

ABSTRACT During its life cycle in intermediate hosts, Toxoplasma gondii exists in two interconverting developmental stages: tachyzoites and bradyzoites. This interconversion is essential for the survival and pathogenicity of the parasite, but little is known about the genetic mechanisms that control this process. We have previously generated tachyzoite-to-bradyzoite differentiation (Tbd−) mutants using chemical mutagenesis and a green fluorescent protein-based selection strategy. The genetic loci responsible for the Tbd− phenotype, however, could not be identified. We have now used an insertional mutagenesis strategy to generate two differentiation mutants: TBD-5 and TBD-6 that switch to bradyzoites at 10 and 50% of wild-type levels, respectively. In TBD-6 there is a single insertion of the mutagenesis vector 164 bp upstream of the transcription start site of a gene encoding a zinc finger protein (ZFP1). Disruption of this locus in wild-type parasites reproduces the decreased stage conversion phenotype. ZFP1 is targeted to the parasite nucleolus by CCHC motifs and significantly altered expression levels are toxic to the parasites. This represents the first identification of a gene necessary for efficient conversion of tachyzoites to bradyzoites.

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MHY1 Encodes a C2H2-Type Zinc Finger Protein That Promotes Dimorphic Transition in the Yeast Yarrowia lipolytica

Journal of Bacteriology ◽

10.1128/jb.181.10.3051-3057.1999 ◽

1999 ◽

Vol 181 (10) ◽

pp. 3051-3057 ◽

Cited By ~ 33

Author(s):

Cleofe A. R. Hurtado ◽

Richard A. Rachubinski

Keyword(s):

Yarrowia Lipolytica ◽

Zinc Finger ◽

Zinc Finger Protein ◽

Pathogenic Fungi ◽

Response Elements ◽

Dimorphic Transition ◽

Adverse Conditions ◽

Finger Protein ◽

Yeast Yarrowia Lipolytica ◽

Hyphal Tip

ABSTRACT The yeast-to-hypha morphological transition (dimorphism) is typical of many pathogenic fungi. Dimorphism has been attributed to changes in temperature and nutritional status and is believed to constitute a mechanism of response to adverse conditions. We have isolated and characterized a gene, MHY1, whose transcription is dramatically increased during the yeast-to-hypha transition inYarrowia lipolytica. Deletion of MHY1 is viable and has no effect on mating, but it does result in a complete inability of cells to undergo mycelial growth. MHY1 encodes a C2H2-type zinc finger protein, Mhy1p, which can bind putative cis-acting DNA stress response elements, suggesting that Mhy1p may act as a transcription factor. Interestingly, Mhy1p tagged with a hemagglutinin epitope was concentrated in the nuclei of actively growing cells found at the hyphal tip.

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Functional importance of Myc-associated zinc finger protein for the human parathyroid hormone (PTH)/PTH-related peptide receptor-1 P2 promoter constitutive activity

Journal of Molecular Endocrinology ◽

10.1677/jme.0.0320099 ◽

2004 ◽

Vol 32 (1) ◽

pp. 99-113 ◽

Cited By ~ 9

Author(s):

C Leroy ◽

D Manen ◽

R Rizzoli ◽

M Lombes ◽

C Silve

Keyword(s):

Parathyroid Hormone ◽

Zinc Finger ◽

Complex I ◽

Promoter Activity ◽

Zinc Finger Protein ◽

Constitutive Activity ◽

Wild Type ◽

Functional Importance ◽

Finger Protein ◽

P2 Promoter

The aim of the present study was to analyze the functional importance for the parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor (PTHR1) gene P2 promoter activity of the putative proximal Myc-associated zinc finger protein (MAZ) site localized at position bp -45 to -39 bp, taking advantage of a G/A mutation identified at position -40 in the human sequence. Wild-type 'full-length' (1285P2) and truncated (760P2) promoter sequences were inserted upstream to the luciferase basic (pLucB) and enhancer (pLucE) reporter gene expression vectors. Transient transfections in osteoblast-like SaOS-2 cells and renal cells (RC.SV3A2) showed that the -40 G/A mutation significantly impaired transcriptional activity of wild-type 1285P2-pLucB and 760P2-pLucE promoter constructs. Further truncation of the P2 sequence demonstrated that the sequence -109/-37 bp was essential for promoter activity. Co-transfection with a MAZ expression vector did not modify the wild-type 1285P2-pLucB construct reporter activity but significantly increased 2-fold the mutated construction activity (P<0.05). Electrophoretic mobility shift assays using SaOS-2 nuclear extracts and a double-stranded DNA fragment encompassing the -45 to -39 putative MAZ site (ds-MAZ-oligo) disclosed two specific DNA-protein complexes. Complex II (fast moving) had a lower affinity for the mutated MAZ motif than for the wild-type MAZ motif while complex I (slow moving) had the same affinity for both wild-type or mutated MAZ sequences. Competition studies with Sp1 consensus oligonucleotide (ds-Sp1-oligo) markedly reduced complex I intensity, with a concomitant increase in that of complex II. Finally, ribonuclease protection assays showed that P2-specific PTHR1 mRNA transcript expression was significantly decreased in SaOS-2 cells transfected with ds-MAZ-oligo as compared with that for control (P<0.001) and ds-Sp1-oligo (P<0.05). Taken together, our studies suggest that the putative -45 to -39 MAZ-binding site regulates the constitutive activity of human PTHR1 P2 promoter.

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