scholarly journals Zap1p, a metalloregulatory protein involved in zinc-responsive transcriptional regulation in Saccharomyces cerevisiae.

1997 ◽  
Vol 17 (9) ◽  
pp. 5044-5052 ◽  
Author(s):  
H Zhao ◽  
D J Eide
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Regulation ◽  
Sequence Similarity ◽  
Ion Homeostasis ◽  
Zinc Ion ◽  
Cysteine Residue ◽  
Terminal Region ◽  
Zinc Uptake ◽  
Uptake System ◽  
High Level

Zinc ion homeostasis in Saccharomyces cerevisiae is controlled primarily through the transcriptional regulation of zinc uptake systems in response to intracellular zinc levels. A high-affinity uptake system is encoded by the ZRT1 gene, and its expression is induced more than 30-fold in zinc-limited cells. A low-affinity transporter is encoded by the ZRT2 gene, and this system is also regulated by zinc. We used a genetic approach to isolate mutants whose ZRT1 expression is no longer repressed in zinc-replete cells, and a new gene, ZAP1, was identified. ZAP1 encodes a 93-kDa protein with sequence similarity to transcriptional activators; the C-terminal 174 amino acids contains five C2H2 zinc finger domains, and the N terminus (residues 1 to 706) has two potential acidic activation domains. The N-terminal region also contains 12% histidine and cysteine residues. The mutant allele isolated, ZAP1-1up, is semidominant and caused high-level expression of ZRT1 and ZRT2 in both zinc-limited and zinc-replete cells. This phenotype is the result of a mutation that substitutes a serine for a cysteine residue in the N-terminal region. A zap1 deletion mutant grew well on zinc-replete media but poorly on zinc-limiting media. This mutant had low-level ZRT1 and ZRT2 expression in zinc-limited as well as zinc-replete cells. These data indicate that Zap1p plays a central role in zinc ion homeostasis by regulating transcription of the zinc uptake system genes in response to zinc. Finally, we present evidence that Zap1p regulates transcription of its own promoter in response to zinc through a positive autoregulatory mechanism.

scholarly journals Investigation of the zinc uptake system of the human fungal pathogen Candida parapsilosis

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Tamás Takács ◽  
Tibor Mihály Németh ◽  
Zóra Szilovics ◽  
Csaba Vágvölgyi ◽  
Duncan Wilson ◽  
...  
Keyword(s):  
Candida Parapsilosis ◽  
Hydrolytic Enzymes ◽  
Zinc Ion ◽  
Zinc Uptake ◽  
Ion Concentration ◽  
Cell Uptake ◽  
Uptake System ◽  
Fungal Cell ◽  
High Zinc ◽  
Acquisition Processes

Candida parapsilosis is the second or third most commonly isolated Candida species from blood cultures and is frequently associated with infections in neonatal intensive care units. Candida species have several virulence factors enabling them to adapt to host environmental conditions and cause infections. These factors include adhesion, biofilm formation, and secretion of hydrolytic enzymes, such as acidic proteinases and lipases. Candida species also obtain heavy metal ions from their environment, such as zinc. Zinc is a cofactor of several proteins and a vital element in cellular mechanisms of the fungi. On the one hand, the host niche represents a zinc-limited environment, that indirectly inhibits microbial growth. In order to survive in such an environment, these pathogens have evolved a zinc transport system that allows them to access bound zinc ions during infection. On the other hand, high zinc ion concentration within the host can also be toxic to microbes e.g. in the phagosomes of Mycobacterium tuberculosis infected macrophages. In case of C. albicans, zinc acquisition processes are intensively studied, but we lack information of the zinc uptake, transfer and homeostasis mechanisms in C. parapsilosis. Here, predicted potential zinc transporters in C. parapsilosis using in silico analyses, generated homozygous knock out mutants and performed their phenotypical characterization by exposing them to various types of stressors and zinc limiting conditions. Furthermore, we analyzed their virulence traits by examining kinetics of fungal cell uptake by macrophages, their killing efficiency and also investigated zinc ion levels in the phagolysosome during in vitro infections

scholarly journals Saccharomyces cerevisiae responds to cold shock by inducing the transcription of genes required for zinc ion homeostasis

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Kristen M Buckmelter ◽  
Bianca A Infanzon ◽  
Elizabeth M Liu ◽  
Olivia S Sakhon ◽  
Kenny R Rodriguez ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cold Shock ◽  
Ion Homeostasis ◽  
Zinc Ion

scholarly journals Tempo and Mode of Ty Element Evolution in Saccharomyces cerevisiae

Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1341-1351 ◽  
Author(s):  
I King Jordan ◽  
John F McDonald
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Negative Selection ◽  
Sequence Variation ◽  
Size Variation ◽  
Sequence Comparisons ◽  
Ty Elements ◽  
Ty Element ◽  
Amino Acid Sequence Variation ◽  
Element Evolution ◽  
High Level

Abstract The Saccharomyces cerevisiae genome contains five families of long terminal repeat (LTR) retrotransposons, Ty1–Ty5. The sequencing of the S. cerevisiae genome provides an unprecedented opportunity to examine the patterns of molecular variation existing among the entire genomic complement of Ty retrotransposons. We report the results of an analysis of the nucleotide and amino acid sequence variation within and between the five Ty element families of the S. cerevisiae genome. Our results indicate that individual Ty element families tend to be highly homogenous in both sequence and size variation. Comparisons of within-element 5′ and 3′ LTR sequences indicate that the vast majority of Ty elements have recently transposed. Furthermore, intrafamily Ty sequence comparisons reveal the action of negative selection on Ty element coding sequences. These results taken together suggest that there is a high level of genomic turnover of S. cerevisiae Ty elements, which is presumably in response to selective pressure to escape host-mediated repression and elimination mechanisms.

scholarly journals Expression of an ATP-binding cassette transporter-encoding gene (YOR1) is required for oligomycin resistance in Saccharomyces cerevisiae.

1995 ◽  
Vol 15 (12) ◽  
pp. 6875-6883 ◽  
Author(s):  
D J Katzmann ◽  
T C Hallstrom ◽  
M Voet ◽  
W Wysock ◽  
J Golin ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fusion Gene ◽  
Sequence Similarity ◽  
Yeast Cells ◽  
Atp Binding ◽  
Zinc Cluster ◽  
Atp Binding Cassette Transporter ◽  
Transporter Family ◽  
Encoding Gene ◽  
Atp Binding Cassette

Semidominant mutations in the PDR1 or PDR3 gene lead to elevated resistance to cycloheximide and oligomycin. PDR1 and PDR3 have been demonstrated to encode zinc cluster transcription factors. Cycloheximide resistance mediated by PDR1 and PDR3 requires the presence of the PDR5 membrane transporter-encoding gene. However, PDR5 is not required for oligomycin resistance. Here, we isolated a gene that is necessary for PDR1- and PDR3-mediated oligomycin resistance. This locus, designated YOR1, causes a dramatic elevation in oligomycin resistance when present in multiple copies. A yor1 strain exhibits oligomycin hypersensitivity relative to an isogenic wild-type strain. In addition, loss of the YOR1 gene blocks the elevation in oligomycin resistance normally conferred by mutant forms of PDR1 or PDR3. The YOR1 gene product is predicted to be a member of the ATP-binding cassette transporter family of membrane proteins. Computer alignment indicates that Yor1p shows striking sequence similarity with multidrug resistance-associated protein, Saccharomyces cerevisiae Ycf1p, and the cystic fibrosis transmembrane conductance regulator. Use of a YOR1-lacZ fusion gene indicates that YOR1 expression is responsive to PDR1 and PDR3. While PDR5 expression is strictly dependent on the presence of PDR1 or PDR3, control of YOR1 expression has a significant PDR1/PDR3-independent component. Taken together, these data indicate that YOR1 provides the link between transcriptional regulation by PDR1 and PDR3 and oligomycin resistance of yeast cells.

scholarly journals Functional Analysis of the Bacillus subtilis Zur Regulon

2002 ◽  
Vol 184 (23) ◽  
pp. 6508-6514 ◽  
Author(s):  
Ahmed Gaballa ◽  
Tao Wang ◽  
Rick W. Ye ◽  
John D. Helmann
Keyword(s):  
Bacillus Subtilis ◽  
Metal Ion ◽  
Dna Microarrays ◽  
Optimal Growth ◽  
Zinc Uptake ◽  
Uptake System ◽  
Mobility Shift ◽  
Transport Pathway ◽  
Dnase I Footprinting ◽  
Transporter Family

ABSTRACT The Bacillus subtilis zinc uptake repressor (Zur) regulates genes involved in zinc uptake. We have used DNA microarrays to identify genes that are derepressed in a zur mutant. In addition to members of the two previously identified Zur-regulated operons (yciC and ycdHI-yceA), we identified two other genes, yciA and yciB, as targets of Zur regulation. Electrophoretic mobility shift experiments demonstrated that all three operons are direct targets of Zur regulation. Zur binds to an ∼28-bp operator upstream of the yciA gene, as judged by DNase I footprinting, and similar operator sites are found preceding each of the previously described target operons, yciC and ycdHI-yceA. Analysis of a yciA-lacZ fusion indicates that this operon is induced under zinc starvation conditions and derepressed in the zur mutant. Phenotypic analyses suggest that the YciA, YciB, and YciC proteins may function as part of the same Zn(II) transport pathway. Mutation of yciA or yciC, singly or in combination, had little effect on growth of the wild-type strain but significantly impaired the growth of the ycdH mutant under conditions of zinc limitation. Since the YciA, YciB, and YciC proteins are not obviously related to any known transporter family, they may define a new class of metal ion uptake system. Mutant strains lacking all three identified zinc uptake systems (yciABC, ycdHI-yceA, and zosA) are dependent on micromolar levels of added zinc for optimal growth.

Functional domains of SIR4, a gene required for position effect regulation in Saccharomyces cerevisiae

1987 ◽  
Vol 7 (12) ◽  
pp. 4441-4452
Author(s):  
M Marshall ◽  
D Mahoney ◽  
A Rose ◽  
J B Hicks ◽  
J R Broach
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Position Effect ◽  
Protein Activity ◽  
Multicomponent Complex ◽  
Mating Type Genes ◽  
Chromosome Iii ◽  
Covalently Linked ◽  
High Level ◽  
Mat Locus

The product of the Saccharomyces cerevisiae SIR4 gene, in conjunction with at least three other gene products, prevents expression of mating-type genes resident at loci at either end of chromosome III, but not of the same genes resident at the MAT locus in the middle of the chromosome. To address the mechanism of this novel position effect regulation, we have conducted a structural and genetic analysis of the SIR4 gene. We have determined the nucleotide sequence of the gene and found that it encodes a lysine-rich, serine-rich protein of 152 kilodaltons. Expression of the carboxy half of the protein complements a chromosomal nonsense mutation of sir4 but not a complete deletion of the gene. These results suggest that SIR4 protein activity resides in two portions of the molecule, but that these domains need not be covalently linked to execute their biological function. We also found that high-level expression of the carboxy domain of the protein yields dominant derepression of the silent loci. This anti-Sir activity can be reversed by increased expression of the SIR3 gene, whose product is normally also required for maintaining repression of the silent loci. These results are consistent with the hypothesis that SIR3 and SIR4 proteins physically associate to form a multicomponent complex required for repression of the silent mating-type loci.

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