1
|
Ó Cinnéide E, Scaife C, Dillon ET, Wolfe KH. Evolution of the Genetic Code in the Ascoideales (CUG-Ser2) Yeast Clade: The Ancestral tRNA-Leu(CAG) Gene Is Retained in Most Saccharomycopsis Species but Is Nonessential and Not Used for Translation. Genome Biol Evol 2024; 16:evae166. [PMID: 39081261 PMCID: PMC11342251 DOI: 10.1093/gbe/evae166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2024] [Indexed: 08/24/2024] Open
Abstract
In the yeast genera Saccharomycopsis and Ascoidea, which comprise the taxonomic order Ascoideales, nuclear genes use a nonstandard genetic code in which CUG codons are translated as serine instead of leucine, due to a tRNA-Ser with the unusual anticodon CAG. However, some species in this clade also retain an ancestral tRNA-Leu gene with the same anticodon. One of these species, Ascoidea asiatica, has been shown to have a stochastic proteome in which proteins contain ∼50% Ser and 50% Leu at CUG codon sites, whereas previously examined Saccharomycopsis species translate CUG only as Ser. Here, we investigated the presence, conservation, and possible functionality of the tRNA-Leu(CAG) gene in the genus Saccharomycopsis. We sequenced the genomes of 23 strains that, together with previously available data, include almost every known species of this genus. We found that most Saccharomycopsis species have genes for both tRNA-Leu(CAG) and tRNA-Ser(CAG). However, tRNA-Leu(CAG) has been lost in Saccharomycopsis synnaedendra and Saccharomycopsis microspora, and its predicted cloverleaf structure is aberrant in all the other Saccharomycopsis species. We deleted the tRNA-Leu(CAG) gene of Saccharomycopsis capsularis and found that it is not essential. Proteomic analyses in vegetative and sporulating cultures of S. capsularis and Saccharomycopsis fermentans showed only translation of CUG as Ser. Despite its unusual structure, the tRNA-Leu(CAG) gene shows evidence of sequence conservation among Saccharomycopsis species, particularly in its acceptor stem and leucine identity elements, which suggests that it may have been retained in order to carry out an unknown nontranslational function.
Collapse
Affiliation(s)
- Eoin Ó Cinnéide
- UCD Conway Institute and School of Medicine, University College Dublin, Dublin, Ireland
| | - Caitriona Scaife
- Mass Spectrometry Core Facility, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Eugène T Dillon
- Mass Spectrometry Core Facility, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Kenneth H Wolfe
- UCD Conway Institute and School of Medicine, University College Dublin, Dublin, Ireland
| |
Collapse
|
2
|
Salman A, Biziaev N, Shuvalova E, Alkalaeva E. mRNA context and translation factors determine decoding in alternative nuclear genetic codes. Bioessays 2024; 46:e2400058. [PMID: 38724251 DOI: 10.1002/bies.202400058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 06/27/2024]
Abstract
The genetic code is a set of instructions that determine how the information in our genetic material is translated into amino acids. In general, it is universal for all organisms, from viruses and bacteria to humans. However, in the last few decades, exceptions to this rule have been identified both in pro- and eukaryotes. In this review, we discuss the 16 described alternative eukaryotic nuclear genetic codes and observe theories of their appearance in evolution. We consider possible molecular mechanisms that allow codon reassignment. Most reassignments in nuclear genetic codes are observed for stop codons. Moreover, in several organisms, stop codons can simultaneously encode amino acids and serve as termination signals. In this case, the meaning of the codon is determined by the additional factors besides the triplets. A comprehensive review of various non-standard coding events in the nuclear genomes provides a new insight into the translation mechanism in eukaryotes.
Collapse
Affiliation(s)
- Ali Salman
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Nikita Biziaev
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina Shuvalova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| |
Collapse
|
3
|
Saeed N, Valiante V, Kufs JE, Hillmann F. The isoprenyl chain length of coenzyme Q mediates the nutritional resistance of fungi to amoeba predation. mBio 2024; 15:e0034224. [PMID: 38747615 PMCID: PMC11237637 DOI: 10.1128/mbio.00342-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/09/2024] [Indexed: 06/13/2024] Open
Abstract
Amoebae are environmental predators feeding on bacteria, fungi, and other eukaryotic microbes. Predatory interactions alter microbial communities and impose selective pressure toward phagocytic resistance or escape which may, in turn, foster virulence attributes. The ubiquitous fungivorous amoeba Protostelium aurantium has a wide prey spectrum in the fungal kingdom but discriminates against members of the Saccharomyces clade, such as Saccharomyces cerevisiae and Candida glabrata. Here, we show that this prey discrimination among fungi is solely based on the presence of ubiquinone as an essential cofactor for the predator. While the amoeba readily fed on fungi with CoQ presenting longer isoprenyl side chain variants CoQ8-10, such as those from the Candida clade, it failed to proliferate on those with shorter CoQ variants, specifically from the Saccharomyces clade (CoQ6). Supplementing non-edible yeast with CoQ9 or CoQ10 rescued the growth of P. aurantium, highlighting the importance of a long isoprenyl side chain. Heterologous biosynthesis of CoQ9 in S. cerevisiae by introducing genes responsible for CoQ9 production from the evolutionary more basic Yarrowia lipolytica complemented the function of the native CoQ6. The results suggest that the use of CoQ6 among members of the Saccharomyces clade might have originated as a predatory escape strategy in fungal lineages and could be retained in organisms that were able to thrive by fermentation. IMPORTANCE Ubiquinones (CoQ) are universal electron carriers in the respiratory chain of all aerobic bacteria and eukaryotes. Usually 8-10 isoprenyl units ensure their localization within the lipid bilayer. Members of the Saccharomyces clade among fungi are unique in using only 6. The reason for this is unclear. Here we provide evidence that the use of CoQ6 efficiently protects these fungi from predation by the ubiquitous fungivorous amoeba Protostelium aurantium which lacks its own biosynthetic pathway for this vitamin. The amoebae were starving on a diet of CoQ6 yeasts which could be complemented by either the addition of longer CoQs or the genetic engineering of a CoQ9 biosynthetic pathway.
Collapse
Affiliation(s)
- Nauman Saeed
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
- Biochemistry/Biotechnology, Faculty of Engineering, Wismar University of Applied Sciences Technology, Business and Design, Wismar, Germany
| | - Vito Valiante
- Biobricks of Microbial Natural Product Syntheses, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
| | - Johann E Kufs
- Genome Engineering and Editing, Faculty of Technology, Bielefeld University, Bielefeld, Germany
| | - Falk Hillmann
- Biochemistry/Biotechnology, Faculty of Engineering, Wismar University of Applied Sciences Technology, Business and Design, Wismar, Germany
| |
Collapse
|
4
|
Zavala B, Dineen L, Fisher KJ, Opulente DA, Harrison MC, Wolters JF, Shen XX, Zhou X, Groenewald M, Hittinger CT, Rokas A, LaBella AL. Genomic factors shaping codon usage across the Saccharomycotina subphylum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.23.595506. [PMID: 38826271 PMCID: PMC11142207 DOI: 10.1101/2024.05.23.595506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Codon usage bias, or the unequal use of synonymous codons, is observed across genes, genomes, and between species. The biased use of synonymous codons has been implicated in many cellular functions, such as translation dynamics and transcript stability, but can also be shaped by neutral forces. The Saccharomycotina, the fungal subphylum containing the yeasts Saccharomyces cerevisiae and Candida albicans , has been a model system for studying codon usage. We characterized codon usage across 1,154 strains from 1,051 species to gain insight into the biases, molecular mechanisms, evolution, and genomic features contributing to codon usage patterns across the subphylum. We found evidence of a general preference for A/T-ending codons and correlations between codon usage bias, GC content, and tRNA-ome size. Codon usage bias is also distinct between the 12 orders within the subphylum to such a degree that yeasts can be classified into orders with an accuracy greater than 90% using a machine learning algorithm trained on codon usage. We also characterized the degree to which codon usage bias is impacted by translational selection. Interestingly, the degree of translational selection was influenced by a combination of genome features and assembly metrics that included the number of coding sequences, BUSCO count, and genome length. Our analysis also revealed an extreme bias in codon usage in the Saccharomycodales associated with a lack of predicted arginine tRNAs. The order contains 24 species, and 23 are computationally predicted to lack tRNAs that decode CGN codons, leaving only the AGN codons to encode arginine. Analysis of Saccharomycodales gene expression, tRNA sequences, and codon evolution suggests that extreme avoidance of the CGN codons is associated with a decline in arginine tRNA function. Codon usage bias within the Saccharomycotina is generally consistent with previous investigations in fungi, which show a role for both genomic features and GC bias in shaping codon usage. However, we find cases of extreme codon usage preference and avoidance along yeast lineages, suggesting additional forces may be shaping the evolution of specific codons.
Collapse
|
5
|
Silva PA, Souza AA, de Oliveira GM, Ramada MHS, Hernández NV, Mora-Montes HM, Bueno RV, Martins-de-Sa D, de Freitas SM, Felipe MSS, Barbosa JARG. An improved expression and purification protocol enables the structural characterization of Mnt1, an antifungal target from Candida albicans. Fungal Biol Biotechnol 2024; 11:5. [PMID: 38715132 PMCID: PMC11077754 DOI: 10.1186/s40694-024-00174-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/22/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Candida albicans is one of the most prevalent fungi causing infections in the world. Mnt1 is a mannosyltransferase that participates in both the cell wall biogenesis and biofilm growth of C. albicans. While the cell wall performs crucial functions in pathogenesis, biofilm growth is correlated with sequestration of drugs by the extracellular matrix. Therefore, antifungals targeting CaMnt1 can compromise fungal development and potentially also render Candida susceptible to drug therapy. Despite its importance, CaMnt1 has not yet been purified to high standards and its biophysical properties are lacking. RESULTS We describe a new protocol to obtain high yield of recombinant CaMnt1 in Komagataella phaffii using methanol induction. The purified protein's identity was confirmed by MALDI-TOF/TOF mass spectroscopy. The Far-UV circular dichroism (CD) spectra demonstrate that the secondary structure of CaMnt1 is compatible with a protein formed by α-helices and β-sheets at pH 7.0. The fluorescence spectroscopy results show that the tertiary structure of CaMnt1 is pH-dependent, with a greater intensity of fluorescence emission at pH 7.0. Using our molecular modeling protocol, we depict for the first time the ternary complex of CaMnt1 bound to its two substrates, which has enabled the identification of residues involved in substrate specificity and catalytic reaction. Our results corroborate the hypothesis that Tyr209 stabilizes the formation of an oxocarbenium ion-like intermediate during nucleophilic attack of the acceptor sugar, opposing the double displacement mechanism proposed by other reports. CONCLUSIONS The methodology presented here can substantially improve the yield of recombinant CaMnt1 expressed in flask-grown yeasts. In addition, the structural characterization of the fungal mannosyltransferase presents novelties that can be exploited for new antifungal drug's development.
Collapse
Affiliation(s)
- Patrícia Alves Silva
- Laboratório de Biofísica Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, 70910-900, Brazil
| | - Amanda Araújo Souza
- Laboratório de Biofísica Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, 70910-900, Brazil
| | - Gideane Mendes de Oliveira
- Laboratório de Biofísica Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, 70910-900, Brazil
| | - Marcelo Henrique Soller Ramada
- Programa de Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, 70790-160, Brazil
| | - Nahúm Valente Hernández
- Departmento de Biologia, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, 36050, Mexico
| | - Héctor Manuel Mora-Montes
- Departmento de Biologia, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, 36050, Mexico
| | - Renata Vieira Bueno
- Laboratório de Biofísica Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, 70910-900, Brazil
| | - Diogo Martins-de-Sa
- Laboratório de Biofísica Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, 70910-900, Brazil
- Genesilico Biotech, Brasília, DF, Brazil
| | - Sonia Maria de Freitas
- Laboratório de Biofísica Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, 70910-900, Brazil
| | - Maria Sueli Soares Felipe
- Programa de Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, 70790-160, Brazil
| | | |
Collapse
|
6
|
Joshi K, Luisi B, Wunderlin G, Saleh S, Lilly A, Okusolubo T, Farabaugh PJ. An evolutionarily conserved phosphoserine-arginine salt bridge in the interface between ribosomal proteins uS4 and uS5 regulates translational accuracy in Saccharomyces cerevisiae. Nucleic Acids Res 2024; 52:3989-4001. [PMID: 38340338 DOI: 10.1093/nar/gkae053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 01/08/2024] [Accepted: 02/08/2024] [Indexed: 02/12/2024] Open
Abstract
Protein-protein and protein-rRNA interactions at the interface between ribosomal proteins uS4 and uS5 are thought to maintain the accuracy of protein synthesis by increasing selection of cognate aminoacyl-tRNAs. Selection involves a major conformational change-domain closure-that stabilizes aminoacyl-tRNA in the ribosomal acceptor (A) site. This has been thought a constitutive function of the ribosome ensuring consistent accuracy. Recently, the Saccharomyces cerevisiae Ctk1 cyclin-dependent kinase was demonstrated to ensure translational accuracy and Ser238 of uS5 proposed as its target. Surprisingly, Ser238 is outside the uS4-uS5 interface and no obvious mechanism has been proposed to explain its role. We show that the true target of Ctk1 regulation is another uS5 residue, Ser176, which lies in the interface opposite to Arg57 of uS4. Based on site specific mutagenesis, we propose that phospho-Ser176 forms a salt bridge with Arg57, which should increase selectivity by strengthening the interface. Genetic data show that Ctk1 regulates accuracy indirectly; the data suggest that the kinase Ypk2 directly phosphorylates Ser176. A second kinase pathway involving TORC1 and Pkc1 can inhibit this effect. The level of accuracy appears to depend on competitive action of these two pathways to regulate the level of Ser176 phosphorylation.
Collapse
Affiliation(s)
- Kartikeya Joshi
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore 21250, USA
| | - Brooke Luisi
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore 21250, USA
| | - Grant Wunderlin
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore 21250, USA
| | - Sima Saleh
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore 21250, USA
| | - Anna Lilly
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore 21250, USA
| | - Temiloluwa Okusolubo
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore 21250, USA
| | - Philip J Farabaugh
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore 21250, USA
| |
Collapse
|
7
|
Devos J, Van Dijck P, Van Genechten W. A multi-colour fluorogenic tag and its application in Candida albicans. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001451. [PMID: 38535895 PMCID: PMC10995450 DOI: 10.1099/mic.0.001451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 03/13/2024] [Indexed: 04/07/2024]
Abstract
Fluorescent proteins (FPs) have always been a crucial part of molecular research in life sciences, including the research into the human fungal pathogen Candida albicans, but have obvious shortcomings such as their relatively large size and long maturation time. However, the next generation of FPs overcome these issues and rely on the binding of a fluorogen for the protein to become fluorescently active. This generation of FPs includes the improved version of Fluorescence activating and Absorption Shifting Tag (iFAST). The binding between the fluorogen and the iFAST protein is reversible, thus resulting in reversible fluorescence. The fluorogens of iFAST are analogues of 4-hydroxylbenzylidene-rhodanine (HBR). These HBR analogues differ in spectral properties depending on functional group substitutions, which gives the iFAST system flexibility in terms of absorbance and emission maxima. In this work we describe and illustrate the application of iFAST as a protein tag and its reversible multi-colour characteristics in C. albicans.
Collapse
Affiliation(s)
- Jonas Devos
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3001 Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3001 Leuven, Belgium
| | - Wouter Van Genechten
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3001 Leuven, Belgium
| |
Collapse
|
8
|
Teli BB, Nagar P, Priyadarshini Y, Poonia P, Natarajan K. A CUG codon-adapted anchor-away toolkit for functional analysis of genes in Candida albicans. mSphere 2024; 9:e0070323. [PMID: 38251906 PMCID: PMC10900876 DOI: 10.1128/msphere.00703-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 12/11/2023] [Indexed: 01/23/2024] Open
Abstract
Promoter shutoff of essential genes in the diploid Candida albicans has often been insufficient to create tight, conditional null alleles due to leaky expression and has been a stumbling block in pathogenesis research. Moreover, homozygous deletion of non-essential genes has often been problematic due to the frequent aneuploidy in the mutant strains. Rapid, conditional depletion of essential genes by the anchor-away strategy has been successfully employed in Saccharomyces cerevisiae and other model organisms. Here, rapamycin mediates the dimerization of human FK506-binding protein (FKBP12) and FKBP12-rapamycin-binding (FRB) domain-containing target protein, resulting in relocalization to altered sub-cellular locations. In this work, we used the ribosomal protein Rpl13 as the anchor and took two nuclear proteins as targets to construct a set of mutants in a proof-of-principle approach. We first constructed a rapamycin-resistant C. albicans strain by introducing a dominant mutation in the CaTOR1 gene and a homozygous deletion of RBP1, the ortholog of FKBP12, a primary target of rapamycin. The FKBP12 and the FRB coding sequences were then CUG codon-adapted for C. albicans by site-directed mutagenesis. Anchor-away strains expressing the essential TBP1 gene or the non-essential SPT8 gene as FRB fusions were constructed. We found that rapamycin caused rapid cessation of growth of the TBP-AA strain within 15 minutes and the SPT8-AA strain phenocopied the constitutive filamentous phenotype of the spt8Δ/spt8Δ mutant. Thus, the anchor-away toolbox for C. albicans developed here can be employed for genome-wide analysis to identify gene function in a rapid and reliable manner, further accelerating anti-fungal drug development in C. albicans. IMPORTANCE Molecular genetic studies thus far have identified ~27% open-reading frames as being essential for the vegetative growth of Candida albicans in rich medium out of a total 6,198 haploid set of open reading frames. However, a major limitation has been to construct rapid conditional alleles of essential C. albicans genes with near quantitative depletion of encoded proteins. Here, we have developed a toolbox for rapid and conditional depletion of genes that would aid studies of gene function of both essential and non-essential genes.
Collapse
Affiliation(s)
- Basharat Bashir Teli
- Laboratory of Eukaryotic Gene Regulation, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Priyanka Nagar
- Laboratory of Eukaryotic Gene Regulation, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Yumnam Priyadarshini
- Laboratory of Eukaryotic Gene Regulation, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Poonam Poonia
- Laboratory of Eukaryotic Gene Regulation, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Krishnamurthy Natarajan
- Laboratory of Eukaryotic Gene Regulation, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| |
Collapse
|
9
|
Lyu Z, Wilson C, Ling J. Translational Fidelity during Bacterial Stresses and Host Interactions. Pathogens 2023; 12:383. [PMID: 36986305 PMCID: PMC10057733 DOI: 10.3390/pathogens12030383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
Translational fidelity refers to accuracy during protein synthesis and is maintained in all three domains of life. Translational errors occur at base levels during normal conditions and may rise due to mutations or stress conditions. In this article, we review our current understanding of how translational fidelity is perturbed by various environmental stresses that bacterial pathogens encounter during host interactions. We discuss how oxidative stress, metabolic stresses, and antibiotics affect various types of translational errors and the resulting effects on stress adaption and fitness. We also discuss the roles of translational fidelity during pathogen-host interactions and the underlying mechanisms. Many of the studies covered in this review will be based on work with Salmonella enterica and Escherichia coli, but other bacterial pathogens will also be discussed.
Collapse
Affiliation(s)
| | | | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| |
Collapse
|
10
|
Genetic Diversity of Human Fungal Pathogens. CURRENT CLINICAL MICROBIOLOGY REPORTS 2023. [DOI: 10.1007/s40588-023-00188-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
|
11
|
Brown AJP. Fungal resilience and host-pathogen interactions: Future perspectives and opportunities. Parasite Immunol 2023; 45:e12946. [PMID: 35962618 PMCID: PMC10078341 DOI: 10.1111/pim.12946] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 01/31/2023]
Abstract
We are constantly exposed to the threat of fungal infection. The outcome-clearance, commensalism or infection-depends largely on the ability of our innate immune defences to clear infecting fungal cells versus the success of the fungus in mounting compensatory adaptive responses. As each seeks to gain advantage during these skirmishes, the interactions between host and fungal pathogen are complex and dynamic. Nevertheless, simply compromising the physiological robustness of fungal pathogens reduces their ability to evade antifungal immunity, their virulence, and their tolerance against antifungal therapy. In this article I argue that this physiological robustness is based on a 'Resilience Network' which mechanistically links and controls fungal growth, metabolism, stress resistance and drug tolerance. The elasticity of this network probably underlies the phenotypic variability of fungal isolates and the heterogeneity of individual cells within clonal populations. Consequently, I suggest that the definition of the fungal Resilience Network represents an important goal for the future which offers the clear potential to reveal drug targets that compromise drug tolerance and synergise with current antifungal therapies.
Collapse
Affiliation(s)
- Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, UK
| |
Collapse
|
12
|
Rabaan AA, Eljaaly K, Alfouzan WA, Mutair AA, Alhumaid S, Alfaraj AH, Aldawood Y, Alsaleh AA, Albayat H, Azmi RA, AlKaabi N, Alzahrani SJ, AlBahrani S, Sulaiman T, Alshukairi AN, Abuzaid AA, Garout M, Ahmad R, Muhammad J. Psychogenetic, genetic and epigenetic mechanisms in Candida auris: Role in drug resistance. J Infect Public Health 2023; 16:257-263. [PMID: 36608452 DOI: 10.1016/j.jiph.2022.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/28/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
In recent years, we are facing the challenge of drug resistance emergence in fungi. The availability of limited antifungals and development of multi-drug resistance in fungal pathogens has become a serious concern in the past years in the health sector. Although several cellular, molecular, and genetic mechanisms have been proposed to explain the drug resistance mechanism in fungi, but a complete understanding of the molecular and genetic mechanisms is still lacking. Besides the genetic mechanism, epigenetic mechanisms are pivotal in the fungal lifecycle and disease biology. However, very little is understood about the role of epigenetic mechanisms in the emergence of multi-drug resistance in fungi, especially in Candida auris (C. auris). The current narrative review summaries the clinical characteristics, genomic organization, and molecular/genetic/epigenetic mechanisms underlying the emergence of drug resistance in C. auris. A very few studies have attempted to evaluate the role of epigenetic mechanisms in C. auris. Furthermore, advanced genetic tools such as the CRISP-Cas9 system can be utilized to elucidate the epigenetic mechanisms and their role in the emergence of multi-drug resistance in C. auris.
Collapse
Affiliation(s)
- Ali A Rabaan
- Molecular Diagnostic Laboratory, Johns Hopkins Aramco Healthcare, Dhahran 31311, Saudi Arabia; College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; Department of Public Health and Nutrition, The University of Haripur, Haripur 22610, Pakistan.
| | - Khalid Eljaaly
- Department of Pharmacy Practice, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Pharmacy Practice and Science Department, College of Pharmacy, University of Arizona, Tucson, AZ, USA
| | - Wadha A Alfouzan
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat 13110, Kuwait; Microbiology Unit, Department of Laboratories, Farwania Hospital, Farwania 85000, Kuwait
| | - Abbas Al Mutair
- Research Center, Almoosa Specialist Hospital, Al-Ahsa 36342, Saudi Arabia; College of Nursing, Princess Norah Bint Abdulrahman University, Riyadh 11564, Saudi Arabia; School of Nursing, Wollongong University, Wollongong, NSW 2522, Australia; Nursing Department, Prince Sultan Military College of Health Sciences, Dhahran 33048, Saudi Arabia
| | - Saad Alhumaid
- Administration of Pharmaceutical Care, Al-Ahsa Health Cluster, Ministry of Health, Al-Ahsa 31982, Saudi Arabia
| | - Amal H Alfaraj
- Pediatric Department, Abqaiq General Hospital, First Eastern Health Cluster, Abqaiq 33261, Saudi Arabia
| | - Yahya Aldawood
- Clinical Laboratory Science Department, Mohammed Al-Mana College for Medical Sciences, Dammam 34222, Saudi Arabia
| | - Abdulmonem A Alsaleh
- Clinical Laboratory Science Department, Mohammed Al-Mana College for Medical Sciences, Dammam 34222, Saudi Arabia
| | - Hawra Albayat
- Infectious Disease Department, King Saud Medical City, Riyadh 7790, Saudi Arabia
| | - Reyouf Al Azmi
- Infection Prevention and Control, Eastern Health Cluster, Dammam 32253, Saudi Arabia
| | - Nawal AlKaabi
- Sheikh Khalifa Medical City, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, 51900, United Arab Emirates; College of Medicine and Health Science, Khalifa University, Abu Dhabi, 127788, United Arab Emirates
| | - Samira J Alzahrani
- Molecular Diagnostic Laboratory, King Fahd Military Medical Complex, Dhahran 31932, Saudi Arabia
| | - Salma AlBahrani
- Infectious Disease Unit, Specialty Internal Medicine, King Fahd Military Medical Complex, Dhahran 31932, Saudi Arabia
| | - Tarek Sulaiman
- Infectious Diseases Section, Medical Specialties Department, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Abeer N Alshukairi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; Department of Medicine, King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia
| | - Abdulmonem A Abuzaid
- Medical Microbiology Department, Security Forces Hospital Programme, Dammam 32314, Saudi Arabia
| | - Mohammed Garout
- Department of Community Medicine and Health Care for Pilgrims, Faculty of Medicine, Umm Al-Qura University, Makkah 21955, Saudi Arabia
| | - Rafiq Ahmad
- Department of Microbiology, The University of Haripur, Haripur 22610, Pakistan
| | - Javed Muhammad
- Department of Microbiology, The University of Haripur, Haripur 22610, Pakistan.
| |
Collapse
|
13
|
Chloroplasts evolved an additional layer of translational regulation based on non-AUG start codons for proteins with different turnover rates. Sci Rep 2023; 13:896. [PMID: 36650197 PMCID: PMC9845219 DOI: 10.1038/s41598-022-27347-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 12/30/2022] [Indexed: 01/18/2023] Open
Abstract
Chloroplasts have evolved from photosynthetic cyanobacteria-like progenitors through endosymbiosis. The chloroplasts of present-day land plants have their own transcription and translation systems that show several similarities with prokaryotic organisms. A remarkable feature of the chloroplast translation system is the use of non-AUG start codons in the protein synthesis of certain genes that are evolutionarily conserved from Algae to angiosperms. However, the biological significance of such use of non-AUG codons is not fully understood. The present study was undertaken to unravel the significance of non-AUG start codons in vivo using the chloroplast genetic engineering approach. For this purpose, stable transplastomic tobacco plants expressing a reporter gene i.e. uidA (GUS) under four different start codons (AUG/UUG/GUG/CUG) were generated and β-glucuronidase (GUS) expression was compared. To investigate further the role of promoter sequences proximal to the start codon, uidA was expressed under two different chloroplast gene promoters psbA and psbC that use AUG and a non-AUG (GUG) start codons, respectively, and also showed significant differences in the DNA sequence surrounding the start codon. Further, to delineate the role of RNA editing that creates AUG start codon by editing non-AUG codons, if any, which is another important feature of the chloroplast transcription and translation system, transcripts were sequenced. In addition, a proteomic approach was used to identify the translation initiation site(s) of GUS and the N-terminal amino acid encoded when expressed under different non-AUG start codons. The results showed that chloroplasts use non-AUG start codons in combination with the translation initiation site as an additional layer of gene regulation to over-express proteins that are required at high levels due to their high rates of turnover.
Collapse
|
14
|
CRISPR-Cas9 Editing Induces Loss of Heterozygosity in the Pathogenic Yeast Candida parapsilosis. mSphere 2022; 7:e0039322. [PMID: 36416551 PMCID: PMC9769790 DOI: 10.1128/msphere.00393-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Genetic manipulation is often used to study gene function. However, unplanned genome changes (including single nucleotide polymorphisms [SNPs], aneuploidy, and loss of heterozygosity [LOH]) can affect the phenotypic traits of the engineered strains. Here, we compared the effect of classical deletion methods (replacing target alleles with selectable markers by homologous recombination) with CRISPR-Cas9 editing in the diploid human-pathogenic yeast Candida parapsilosis. We sequenced the genomes of 9 isolates that were modified using classic recombination methods and 12 that were edited using CRISPR-Cas9. As a control, the genomes of eight isolates that were transformed with a Cas9-expressing plasmid in the absence of a guide RNA were also sequenced. Following gene manipulation using classic homologous recombination, only one strain exhibited extensive LOH near the targeted gene (8.9 kb), whereas another contained multiple LOH events not associated with the intended modification. In contrast, large regions of LOH (up to >1,100 kb) were observed in most CRISPR-Cas9-edited strains. LOH most commonly occurred adjacent to the Cas9 cut site and extended to the telomere in four isolates. In two isolates, we observed LOH on chromosomes that were not targeted by CRISPR-Cas9. Among the CRISPR-edited isolates, two exhibited cysteine and methionine auxotrophy caused by LOH at a heterozygous site in MET10, approximately 11 and 157 kb downstream from the Cas9 target site, respectively. C. parapsilosis isolates have relatively low levels of heterozygosity. However, our results show that mutation complementation to confirm observed phenotypes is required when using CRISPR-Cas9. IMPORTANCE CRISPR-Cas9 has greatly streamlined gene editing and is now the gold standard and first choice for genetic engineering. However, we show that in diploid species, extra care should be taken in confirming the cause of any phenotypic changes observed. We show that the Cas9-induced double-strand break is often associated with loss of heterozygosity in the asexual diploid human fungal pathogen Candida parapsilosis. This can result in deleterious heterozygous variants (e.g., stop gain in one allele) becoming homozygous, resulting in unplanned phenotypic changes. Our results stress the importance of mutation complementation even when using CRISPR-Cas9.
Collapse
|
15
|
Analyzing the human gut mycobiome – a short guide for beginners. Comput Struct Biotechnol J 2022; 20:608-614. [PMID: 35116136 PMCID: PMC8790610 DOI: 10.1016/j.csbj.2022.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/04/2022] [Accepted: 01/08/2022] [Indexed: 12/30/2022] Open
Abstract
The human body is a dynamic ecosystem consisting of millions of microbes which are often comprised under the term microbiome. Compared to bacteria, which count for the overwhelming majority of the microbiome, the number of human-associated fungi is small and often underestimated. Nonetheless, they can be found in different host niches such as the gut, the oral cavity and the skin. The fungal community has several potential roles in health and disease of the human host. In this review we will focus on intestinal fungi and their interaction with the host as well as bacteria. We also summarize technical challenges and possible biases researchers must be aware of when conducting mycobiome analysis.
Collapse
|
16
|
Interactions of Both Pathogenic and Nonpathogenic CUG Clade Candida Species with Macrophages Share a Conserved Transcriptional Landscape. mBio 2021; 12:e0331721. [PMID: 34903044 PMCID: PMC8669484 DOI: 10.1128/mbio.03317-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Candida species are a leading cause of opportunistic, hospital-associated bloodstream infections with high mortality rates, typically in immunocompromised patients. Several species, including Candida albicans, the most prevalent cause of infection, belong to the monophyletic CUG clade of yeasts. Innate immune cells such as macrophages are crucial for controlling infection, and C. albicans responds to phagocytosis by a coordinated induction of pathways involved in catabolism of nonglucose carbon sources, termed alternative carbon metabolism, which together are essential for virulence. However, the interactions of other CUG clade species with macrophages have not been characterized. Here, we analyzed transcriptional responses to macrophage phagocytosis by six Candida species across a range of virulence and clinical importance. We define a core induced response common to pathogenic and nonpathogenic species alike, heavily weighted to alternative carbon metabolism. One prominent pathogen, Candida parapsilosis, showed species-specific expansion of phagocytosis-responsive genes, particularly metabolite transporters. C. albicans and Candida tropicalis, the other prominent pathogens, also had species-specific responses, but these were largely comprised of functionally uncharacterized genes. Transcriptional analysis of macrophages also demonstrated highly correlated proinflammatory transcriptional responses to different Candida species that were largely independent of fungal viability, suggesting that this response is driven by recognition of conserved cell wall components. This study significantly broadens our understanding of host interactions in CUG clade species, demonstrating that although metabolic plasticity is crucial for virulence in Candida, it alone is not sufficient to confer pathogenicity. Instead, we identify sets of mostly uncharacterized genes that may explain the evolution of pathogenicity.
Collapse
|
17
|
Zhang H, Wu J, Lyu Z, Ling J. Impact of alanyl-tRNA synthetase editing deficiency in yeast. Nucleic Acids Res 2021; 49:9953-9964. [PMID: 34500470 PMCID: PMC8464055 DOI: 10.1093/nar/gkab766] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 11/12/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that provide the ribosome with aminoacyl-tRNA substrates for protein synthesis. Mutations in aaRSs lead to various neurological disorders in humans. Many aaRSs utilize editing to prevent error propagation during translation. Editing defects in alanyl-tRNA synthetase (AlaRS) cause neurodegeneration and cardioproteinopathy in mice and are associated with microcephaly in human patients. The cellular impact of AlaRS editing deficiency in eukaryotes remains unclear. Here we use yeast as a model organism to systematically investigate the physiological role of AlaRS editing. Our RNA sequencing and quantitative proteomics results reveal that AlaRS editing defects surprisingly activate the general amino acid control pathway and attenuate the heatshock response. We have confirmed these results with reporter and growth assays. In addition, AlaRS editing defects downregulate carbon metabolism and attenuate protein synthesis. Supplying yeast cells with extra carbon source partially rescues the heat sensitivity caused by AlaRS editing deficiency. These findings are in stark contrast with the cellular effects caused by editing deficiency in other aaRSs. Our study therefore highlights the idiosyncratic role of AlaRS editing compared with other aaRSs and provides a model for the physiological impact caused by the lack of AlaRS editing.
Collapse
Affiliation(s)
- Hong Zhang
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Jiang Wu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| |
Collapse
|
18
|
Hsu IS, Strome B, Lash E, Robbins N, Cowen LE, Moses AM. A functionally divergent intrinsically disordered region underlying the conservation of stochastic signaling. PLoS Genet 2021; 17:e1009629. [PMID: 34506483 PMCID: PMC8457507 DOI: 10.1371/journal.pgen.1009629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/22/2021] [Accepted: 08/06/2021] [Indexed: 12/18/2022] Open
Abstract
Stochastic signaling dynamics expand living cells' information processing capabilities. An increasing number of studies report that regulators encode information in their pulsatile dynamics. The evolutionary mechanisms that lead to complex signaling dynamics remain uncharacterized, perhaps because key interactions of signaling proteins are encoded in intrinsically disordered regions (IDRs), whose evolution is difficult to analyze. Here we focused on the IDR that controls the stochastic pulsing dynamics of Crz1, a transcription factor in fungi downstream of the widely conserved calcium signaling pathway. We find that Crz1 IDRs from anciently diverged fungi can all respond transiently to calcium stress; however, only Crz1 IDRs from the Saccharomyces clade support pulsatility, encode extra information, and rescue fitness in competition assays, while the Crz1 IDRs from distantly related fungi do none of the three. On the other hand, we find that Crz1 pulsing is conserved in the distantly related fungi, consistent with the evolutionary model of stabilizing selection on the signaling phenotype. Further, we show that a calcineurin docking site in a specific part of the IDRs appears to be sufficient for pulsing and show evidence for a beneficial increase in the relative calcineurin affinity of this docking site. We propose that evolutionary flexibility of functionally divergent IDRs underlies the conservation of stochastic signaling by stabilizing selection.
Collapse
Affiliation(s)
- Ian S. Hsu
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
| | - Bob Strome
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
| | - Emma Lash
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Alan M. Moses
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
- Department of Computer Science, University of Toronto, Toronto, Canada
- * E-mail:
| |
Collapse
|
19
|
Guimarães AR, Correia I, Sousa I, Oliveira C, Moura G, Bezerra AR, Santos MAS. tRNAs as a Driving Force of Genome Evolution in Yeast. Front Microbiol 2021; 12:634004. [PMID: 33776966 PMCID: PMC7990762 DOI: 10.3389/fmicb.2021.634004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/01/2021] [Indexed: 11/29/2022] Open
Abstract
Transfer RNAs (tRNAs) are widely known for their roles in the decoding of the linear mRNA information into amino acid sequences of proteins. They are also multifunctional platforms in the translation process and have other roles beyond translation, including sensing amino acid abundance, interacting with the general stress response machinery, and modulating cellular adaptation, survival, and death. In this mini-review, we focus on the emerging role of tRNA genes in the organization and modification of the genomic architecture of yeast and the role of tRNA misexpression and decoding infidelity in genome stability, evolution, and adaption. We discuss published work showing how quickly tRNA genes can mutate to meet novel translational demands, how tRNAs speed up genome evolution, and how tRNA genes can be sites of genomic instability. We highlight recent works showing that loss of tRNA decoding fidelity and small alterations in tRNA expression have unexpected and profound impacts on genome stability. By dissecting these recent evidence, we hope to lay the groundwork that prompts future investigations on the mechanistic interplay between tRNAs and genome modification that likely triggers genome evolution.
Collapse
Affiliation(s)
- Ana Rita Guimarães
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Inês Correia
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Inês Sousa
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Carla Oliveira
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Gabriela Moura
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Ana Rita Bezerra
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Manuel A S Santos
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| |
Collapse
|
20
|
What do we know about the biology of the emerging fungal pathogen of humans Candida auris? Microbiol Res 2020; 242:126621. [PMID: 33096325 DOI: 10.1016/j.micres.2020.126621] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/25/2020] [Accepted: 10/04/2020] [Indexed: 02/07/2023]
Abstract
Candida auris is a worrisome fungal pathogen of humans which emerged merely about a decade ago. Ever since then the scientific community worked hard to understand clinically relevant traits, such as virulence factors, antifungal resistance mechanisms, and its ability to adhere to human skin and medical devices. Whole-genome sequencing of clinical isolates and epidemiological studies outlining the path of nosocomial outbreaks have been the focus of research into this pathogenic and multidrug-resistant yeast since its first description in 2009. More recently, work was started by several laboratories to explore the biology of C. auris. Here, we review the insights of studies characterizing the mechanisms underpinning antifungal drug resistance, biofilm formation, morphogenetic switching, cell aggregation, virulence, and pathogenicity of C. auris. We conclude that, although some progress has been made, there is still a long journey ahead of us, before we fully understand this novel pathogen. Critically important is the development of molecular tools for C. auris to make this fungus genetically tractable and traceable. This will allow an in-depth molecular dissection of the life cycle of C. auris, of its characteristics while interacting with the human host, and the mechanisms it employs to avoid being killed by antifungals and the immune system.
Collapse
|
21
|
Maxwell PH. Diverse transposable element landscapes in pathogenic and nonpathogenic yeast models: the value of a comparative perspective. Mob DNA 2020; 11:16. [PMID: 32336995 PMCID: PMC7175516 DOI: 10.1186/s13100-020-00215-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/16/2020] [Indexed: 12/14/2022] Open
Abstract
Genomics and other large-scale analyses have drawn increasing attention to the potential impacts of transposable elements (TEs) on their host genomes. However, it remains challenging to transition from identifying potential roles to clearly demonstrating the level of impact TEs have on genome evolution and possible functions that they contribute to their host organisms. I summarize TE content and distribution in four well-characterized yeast model systems in this review: the pathogens Candida albicans and Cryptococcus neoformans, and the nonpathogenic species Saccharomyces cerevisiae and Schizosaccharomyces pombe. I compare and contrast their TE landscapes to their lifecycles, genomic features, as well as the presence and nature of RNA interference pathways in each species to highlight the valuable diversity represented by these models for functional studies of TEs. I then review the regulation and impacts of the Ty1 and Ty3 retrotransposons from Saccharomyces cerevisiae and Tf1 and Tf2 retrotransposons from Schizosaccharomyces pombe to emphasize parallels and distinctions between these well-studied elements. I propose that further characterization of TEs in the pathogenic yeasts would enable this set of four yeast species to become an excellent set of models for comparative functional studies to address outstanding questions about TE-host relationships.
Collapse
|
22
|
Correlating Genotype and Phenotype in the Asexual Yeast Candida orthopsilosis Implicates ZCF29 in Sensitivity to Caffeine. G3-GENES GENOMES GENETICS 2019; 9:3035-3043. [PMID: 31352406 PMCID: PMC6723125 DOI: 10.1534/g3.119.400348] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Candida orthopsilosis is diploid asexual yeast that causes human disease. Most C. orthopsilosis isolates arose from at least four separate hybridizations between related, but not identical, parents. Here, we used population genomics data to correlate genotypic and phenotypic variation in 28 C. orthopsilosis isolates. We used cosine similarity scores to identify 65 variants with potential high-impact (deleterious effects) that correlated with specific phenotypes. Of these, 19 were Single Nucleotide Polymorphisms (SNPs) that changed stop or start codons, or splice sites. One variant resulted in a premature stop codon in both alleles of the gene ZCF29 in C. orthopsilosis isolate 185, which correlated with sensitivity to nystatin and caffeine. We used CRISPR-Cas9 editing to introduce this polymorphism into two resistant C. orthopsilosis isolates. Introducing the stop codon resulted in sensitivity to caffeine and to ketoconazole, but not to nystatin. Our analysis shows that it is possible to associate genomic variants with phenotype in asexual Candida species, but that only a small amount of genomic variation can be easily explored.
Collapse
|
23
|
A new toolkit for gene tagging in Candida albicans containing recyclable markers. PLoS One 2019; 14:e0219715. [PMID: 31295309 PMCID: PMC6622542 DOI: 10.1371/journal.pone.0219715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 06/28/2019] [Indexed: 12/20/2022] Open
Abstract
Gene manipulation and epitope tagging are essential tools for understanding the molecular function of specific genes. The opportunistic human pathogen Candida albicans is a diploid fungus that utilizes a non-canonical genetic code. Since selection markers available in this organism are scarce, several tools based on recyclable markers have been developed for gene disruption, such as the Clox system. This system relies on the Cre recombinase, which recycles selection markers flanked by loxP sites with high efficiency, facilitating single marker or multi-marker recycling. However, PCR-based modules for epitope tagging, such the pFA-modules, mainly use limited non-recyclable auxotrophic markers. To solve this problem, we have used a Gibson assembly strategy to construct a set of new plasmids where the auxotrophic markers of the pFA vectors were swapped with five recyclable marker modules of the Clox system, enhancing the versatility of the pFA plasmids. This new toolkit, named pFA-Clox, is composed of 36 new vectors for gene disruption and epitope tagging (GFP, 3xGFP, mCherry, 3xHA, 5xmyc and TAP). These plasmids contain the dominant NAT1 marker, as well as URA3, HIS1 and ARG4 cassettes, thereby permitting functional analysis of laboratory strains as well as clinical isolates of C. albicans. In summary, we have adapted the Clox system to the pFA-backbone vectors. Thus, the set of primers used for the amplification of previously published pFA modules can also be utilized in this new pFA-Clox system. Therefore, this new toolkit harbors the advantages of both systems, allowing accelerated gene modification strategies that could reduce time and costs in strain construction for C. albicans.
Collapse
|
24
|
Screening of Candida albicans GRACE library revealed a unique pattern of biofilm formation under repression of the essential gene ILS1. Sci Rep 2019; 9:9187. [PMID: 31235750 PMCID: PMC6591175 DOI: 10.1038/s41598-019-45624-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 06/06/2019] [Indexed: 01/19/2023] Open
Abstract
Candida albicans biofilm formation is governed by a regulatory circuit comprising nine transcription factors which control a network of target genes. However, there are still unknown genes contributing to biofilm features. Thus, the GRACE library was screened to identify genes involved in mature biofilm development. Twenty-nine conditional mutants were selected for a second screening revealing three groups of genes: twenty- two conditional mutants were defective for normal growth and unable to form biofilms; six strains, conditionally defective in genes ARC40, ARC35, ORF19.2438, SKP1, ERG6, and ADE5,7 that are likely essential or involved in general cell processes, grew normally as free-floating cells but produced less biofilm; finally, the conditional strain for a putative essential isoleucyl- tRNA synthetase gene, ILS1, was unable to grow as yeast-phase cells but was capable of producing a tridimensional biofilm structure in spite of reduced metabolic activity. This unique biofilm still relied on the classical biofilm genes, while it differentially induced groups of genes involved in adhesion, protein synthesis, cell wall organization, and protein folding. Although the conditional mutant repressed genes annotated for morphology and homeostasis processes affecting morphology and metabolism, the dynamic cell growth enabled the formation of a complex biofilm community independent of ILS1.
Collapse
|
25
|
Hasegawa S, Yamada Y, Iwanami N, Nakayama Y, Nakayama H, Iwatani S, Oura T, Kajiwara S. Identification and functional characterization of Candida albicans mannose-ethanolamine phosphotransferase (Mcd4p). Curr Genet 2019; 65:1251-1261. [PMID: 31073667 DOI: 10.1007/s00294-019-00987-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 11/28/2022]
Abstract
Glycosylphosphatidylinositol (GPI) is an important compound for the growth of fungi, because GPI-anchored proteins including glycosyltransferases and adhesins are involved in cell-wall integrity, adhesion, and nutrient uptake in this organism. In this study, we examined orf19.5244 in the genome database of the pathogenic fungus Candida albicans, a homologue of the Saccharomyces cerevisiae mannose-ethanolamine phosphotransferase gene, MCD4, which plays a role in GPI synthesis. Expression of this homologue, designated CaMCD4, restored cell growth in a defective conditional mcd4 mutant of S. cerevisiae, Scmcd4t, in which expression of native MCD4 was repressed in the presence of doxycycline (Dox). Analysis of radiolabeled lipids showed that the accumulation of abnormal GPI anchor precursors in Scmcd4t decreased markedly upon expression of CaMCD4. Moreover, we constructed a single mutant (Camcd4/CaMCD4) and a conditional double mutant (Camcd4/Camcd4t) at the MCD4 locus of C. albicans. Repression of CaMCD4 expression by Dox led to a decrease in growth and appearance of abnormal morphology in C. albicans, both in vitro and in a silkworm infection model. These results suggest that CaMcd4p is indispensable for growth of C. albicans both in vitro and in infected hosts and a candidate target for the development of new antifungals.
Collapse
Affiliation(s)
- Satoru Hasegawa
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J3-07 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Yuimi Yamada
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J3-07 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Noboru Iwanami
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J3-07 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Yusuke Nakayama
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J3-07 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Hironobu Nakayama
- Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Minami-Tamagakicho, 3500-3, Suzuka, Mie, 513-8670, Japan
| | - Shun Iwatani
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J3-07 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Takahiro Oura
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J3-07 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Susumu Kajiwara
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J3-07 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan.
| |
Collapse
|
26
|
Abstract
Candida species are a major cause of infection worldwide. The species associated with infection vary with geographical location and with patient population. Infection with Candida tropicalis is particularly common in South America and Asia, and Candida parapsilosis infections are more common in the very young. Molecular methods for manipulating the genomes of these species are still lacking. We describe a simple and efficient CRISPR-based gene editing system that can be applied in the C. parapsilosis species group, including the sister species Candida orthopsilosis and Candida metapsilosis. We have also constructed a separate system for gene editing in C. tropicalis. Many Candida species that cause infection have diploid genomes and do not undergo classical meiosis. The application of clustered regularly interspaced short palindromic repeat-Cas9 (CRISPR-Cas9) gene editing systems has therefore greatly facilitated the generation of gene disruptions and the introduction of specific polymorphisms. However, CRISPR methods are not yet available for all Candida species. We describe here an adaption of a previously developed CRISPR system in Candida parapsilosis that uses an autonomously replicating plasmid. Guide RNAs can be introduced in a single cloning step and are released by cleavage between a tRNA and a ribozyme. The plasmid also contains CAS9 and a selectable nourseothricin SAT1 marker. It can be used for markerless editing in C. parapsilosis, C. orthopsilosis, and C. metapsilosis. We also show that CRISPR can easily be used to introduce molecular barcodes and to reintroduce wild-type sequences into edited strains. Heterozygous mutations can be generated, either by careful selection of the distance between the polymorphism and the Cas9 cut site or by providing two different repair templates at the same time. In addition, we have constructed a different autonomously replicating plasmid for CRISPR-Cas9 editing in Candida tropicalis. We show that editing can easily be carried out in multiple C. tropicalis isolates. Nonhomologous end joining (NHEJ) repair occurs at a high level in C. metapsilosis and C. tropicalis. IMPORTANCECandida species are a major cause of infection worldwide. The species associated with infection vary with geographical location and with patient population. Infection with Candida tropicalis is particularly common in South America and Asia, and Candida parapsilosis infections are more common in the very young. Molecular methods for manipulating the genomes of these species are still lacking. We describe a simple and efficient CRISPR-based gene editing system that can be applied in the C. parapsilosis species group, including the sister species Candida orthopsilosis and Candida metapsilosis. We have also constructed a separate system for gene editing in C. tropicalis.
Collapse
|
27
|
Fraga JS, Sárkány Z, Silva A, Correia I, Pereira PJB, Macedo-Ribeiro S. Genetic code ambiguity modulates the activity of a C. albicans MAP kinase linked to cell wall remodeling. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:654-661. [PMID: 30797104 DOI: 10.1016/j.bbapap.2019.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/13/2019] [Accepted: 02/18/2019] [Indexed: 12/28/2022]
Abstract
The human fungal pathogen Candida albicans ambiguously decodes the universal leucine CUG codon predominantly as serine but also as leucine. C. albicans has a high capacity to survive and proliferate in adverse environments but the rate of leucine incorporation fluctuates in response to different stress conditions. C. albicans is adapted to tolerate this ambiguous translation through a mechanism that combines drastic decrease in CUG usage and reduction of CUG-encoded residues in conserved positions in the protein sequences. However, in a few proteins, the residues encoded by CUG codons are found in strictly conserved positions, suggesting that this genetic code alteration might have a functional impact. One such example is Cek1, a central signaling protein kinase that contains a single CUG-encoded residue at a conserved position, whose identity might regulate the correct flow of information across the MAPK cascade. Here we show that insertion of a leucine at the CUG-encoded position decreases the stability of Cek1, apparently without major structural alterations. In contrast, incorporation of a serine residue at the CUG position induces the autophosphorylation of the conserved tyrosine residue of the Cek1 231TEY233 motif, and increases its intrinsic kinase activity in vitro. These findings show that CUG ambiguity modulates the activity of Cek1, a key kinase directly linked to morphogenesis and virulence in C. albicans.
Collapse
Affiliation(s)
- Joana S Fraga
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Zsuzsa Sárkány
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Alexandra Silva
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Inês Correia
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Pedro José Barbosa Pereira
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Sandra Macedo-Ribeiro
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
| |
Collapse
|
28
|
Abstract
CRISPR technology is a new and efficient way to edit genomes, but it is also an appealing way to regulate gene expression. We have implemented CRISPR as a gene expression platform in Candida albicans using fusions between a Cas9 inactive enzyme and specific repressors or activators and demonstrated its functionality. This will allow future manipulation of complex virulence pathways in this important fungal pathogen. Clustered regularly interspaced short palindromic repeat (CRISPR) methodology is not only an efficient tool in gene editing but also an attractive platform to facilitate DNA, RNA, and protein interactions. We describe here the implementation of a CRISPR-based system to regulate expression in the clinically important yeast Candida albicans. By fusing an allele of Streptococcus pyogenes Cas9 devoid of nuclease activity to a transcriptional repressor (Nrg1) or activator (Gal4), we were able to show specific repression or activation of the tester gene CAT1, encoding the cytosolic catalase. We generated strains where a 1.6-kbp upstream regulatory region of CAT1 controls the expression of the green fluorescent protein (GFP) and demonstrated the functionality of the constructs by quantitative PCR (qPCR), flow cytometry, and analysis of sensitivity/resistance to hydrogen peroxide. Activation and repression were strongly dependent on the position of the complex in this regulatory region. We also improved transcriptional activation using an RNA scaffolding strategy to allow interaction of inactive variants of Cas9 (dCas9) with the RNA binding protein MCP (monocyte chemoattractant protein) fused to the VP64 activator. The strategy shown here may facilitate the analysis of complex regulatory traits in this fungal pathogen. IMPORTANCE CRISPR technology is a new and efficient way to edit genomes, but it is also an appealing way to regulate gene expression. We have implemented CRISPR as a gene expression platform in Candida albicans using fusions between a Cas9 inactive enzyme and specific repressors or activators and demonstrated its functionality. This will allow future manipulation of complex virulence pathways in this important fungal pathogen.
Collapse
|
29
|
Frazer C, Hernday AD, Bennett RJ. Monitoring Phenotypic Switching in Candida albicans and the Use of Next-Gen Fluorescence Reporters. ACTA ACUST UNITED AC 2019; 53:e76. [PMID: 30747494 DOI: 10.1002/cpmc.76] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Candida albicans is an opportunistic human fungal pathogen that is able to cause both mucosal and systemic infections. It is also a frequent human commensal, where it is typically found inhabiting multiple niches including the gastrointestinal tract. One of the most remarkable features of C. albicans biology is its ability to undergo heritable and reversible switching between different phenotypic states, a phenomenon known as phenotypic switching. This is best exemplified by the white-opaque switch, in which cells undergo epigenetic transitions between two alternative cellular states. Here, we describe assays to quantify the frequency of switching between states, as well as methods to help identify cells in different phenotypic states. We also describe the use of environmental cues that can induce switching into either the white or opaque state. Finally, we introduce the use of mNeonGreen and mScarlet fluorescent proteins that have been optimized for use in C. albicans and which outperform commonly used fluorescent proteins for both fluorescence microscopy and flow cytometry. © 2019 by John Wiley & Sons, Inc.
Collapse
Affiliation(s)
- Corey Frazer
- Molecular Microbiology and Immunology Department, Brown University, Providence, Rhode Island
| | - Aaron D Hernday
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, Merced, California.,Quantitative and Systems Biology Graduate Program, School of Natural Sciences, University of California, Merced, Merced, California
| | - Richard J Bennett
- Molecular Microbiology and Immunology Department, Brown University, Providence, Rhode Island
| |
Collapse
|
30
|
Abstract
The concept of the species ‘pan-genome’, the union of ‘core’ conserved genes and all ‘accessory’ non-conserved genes across all strains of a species, was first proposed in prokaryotes to account for intraspecific variability. Species pan-genomes have been extensively studied in prokaryotes, but evidence of species pan-genomes has also been demonstrated in eukaryotes such as plants and fungi. Using a previously published methodology based on sequence homology and conserved microsynteny, in addition to bespoke pipelines, we have investigated the pan-genomes of four model fungal species: Saccharomyces cerevisiae, Candida albicans, Cryptococcus neoformans var. grubii and Aspergillus fumigatus. Between 80 and 90 % of gene models per strain in each of these species are core genes that are highly conserved across all strains of that species, many of which are involved in housekeeping and conserved survival processes. In many of these species, the remaining ‘accessory’ gene models are clustered within subterminal regions and may be involved in pathogenesis and antimicrobial resistance. Analysis of the ancestry of species core and accessory genomes suggests that fungal pan-genomes evolve by strain-level innovations such as gene duplication as opposed to wide-scale horizontal gene transfer. Our findings lend further supporting evidence to the existence of species pan-genomes in eukaryote taxa.
Collapse
Affiliation(s)
- Charley G P McCarthy
- 1Genome Evolution Laboratory, Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.,2Human Health Research Institute, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - David A Fitzpatrick
- 1Genome Evolution Laboratory, Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.,2Human Health Research Institute, Maynooth University, Maynooth, Co. Kildare, Ireland
| |
Collapse
|
31
|
Van Ende M, Wijnants S, Van Dijck P. Sugar Sensing and Signaling in Candida albicans and Candida glabrata. Front Microbiol 2019; 10:99. [PMID: 30761119 PMCID: PMC6363656 DOI: 10.3389/fmicb.2019.00099] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/16/2019] [Indexed: 12/30/2022] Open
Abstract
Candida species, such as Candida albicans and Candida glabrata, cause infections at different host sites because they adapt their metabolism depending on the available nutrients. They are able to proliferate under both nutrient-rich and nutrient-poor conditions. This adaptation is what makes these fungi successful pathogens. For both species, sugars are very important nutrients and as the sugar level differs depending on the host niche, different sugar sensing systems must be present. Saccharomyces cerevisiae has been used as a model for the identification of these sugar sensing systems. One of the main carbon sources for yeast is glucose, for which three different pathways have been described. First, two transporter-like proteins, ScSnf3 and ScRgt2, sense glucose levels resulting in the induction of different hexose transporter genes. This situation is comparable in C. albicans and C. glabrata, where sensing of glucose by CaHgt4 and CgSnf3, respectively, also results in hexose transporter gene induction. The second glucose sensing mechanism in S. cerevisiae is via the G-protein coupled receptor ScGpr1, which causes the activation of the cAMP/PKA pathway, resulting in rapid adaptation to the presence of glucose. The main components of this glucose sensing system are also conserved in C. albicans and C. glabrata. However, it seems that the ligand(s) for CaGpr1 are not sugars but lactate and methionine. In C. glabrata, this pathway has not yet been investigated. Finally, the glucose repression pathway ensures repression of respiration and repression of the use of alternative carbon sources. This pathway is not well characterized in Candida species. It is important to note that, apart from glucose, other sugars and sugar-analogs, such as N-acetylglucosamine in the case of C. albicans, are also important carbon sources. In these fungal pathogens, sensing sugars is important for a number of virulence attributes, including adhesion, oxidative stress resistance, biofilm formation, morphogenesis, invasion, and antifungal drug tolerance. In this review, the sugar sensing and signaling mechanisms in these Candida species are compared to S. cerevisiae.
Collapse
Affiliation(s)
- Mieke Van Ende
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Stefanie Wijnants
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| |
Collapse
|
32
|
Linder T. Phenotypical characterisation of a putative ω-amino acid transaminase in the yeast Scheffersomyces stipitis. Arch Microbiol 2018; 201:185-192. [PMID: 30519708 PMCID: PMC6514085 DOI: 10.1007/s00203-018-1608-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 01/05/2023]
Abstract
Phylogenetic analysis of class III transaminases in the budding yeasts Lachancea kluyveri, Saccharomyces cerevisiae and Scheffersomyces stipitis identified a hitherto uncharacterised Sch. stipitis transaminase encoded by the PICST_54153 gene, which clustered with previously described γ-amino butyric acid (GABA) and β-alanine transaminases. Deletion of the PICST_54153 gene in Sch. stipitis resulted in a complete loss in the utilisation of β-alanine and β-ureidopropionic acid as nitrogen sources, while growth on 1,3-diaminopropane displayed a significant lag phase compared to the wild-type control. It was therefore concluded that the Sch. stipitis PICST_54153 gene likely encodes a β-alanine transaminase. However, minor growth defects when 1,4-diaminobutane or 1,5-diaminopentane was provided as the nitrogen source suggested that the Picst_54153 transaminase may also participate in the catabolism of other diamine-derived ω-amino acids. Unexpectedly, the ∆picst_54153 deletion mutant failed to grow on solid minimal medium in the presence of 5 mM β-alanine even if a preferred nitrogen source was provided.
Collapse
Affiliation(s)
- Tomas Linder
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07, Uppsala, Sweden.
| |
Collapse
|
33
|
Manohar K, Peroumal D, Acharya N. TLS dependent and independent functions of DNA polymerase eta (Polη/Rad30) from Pathogenic Yeast Candida albicans. Mol Microbiol 2018; 110:707-727. [PMID: 29907984 DOI: 10.1111/mmi.14004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 06/03/2018] [Accepted: 06/06/2018] [Indexed: 02/06/2023]
Abstract
Polη, a unique TLS DNA polymerase that promotes efficient bypass of UV-induced CPDs and cisplatin adducts, has not been explored in Candida species yet. Here, we show that CaPolη plays a vital role in protecting Candida albicans genome from diverse array of DNA damaging agents, not limited to UV and cisplatin. Polη deficient strain did not exhibit any hyphal development in the presence of UV and cisplatin while the wild type strain profusely developed DNA damage induced filamentation. The polarized growth induced by HU and MMS was found to be Polη independent. No common regulatory pathway of morphogenesis operates in C. albicans due to genomic stress, rather Polη branches away from RAD53 dependent pathway to be specific to UV/cisplatin. Interestingly, serum that does not inflict any DNA damage also induces hyphal growth in C. albicans, and requires a functionally active Polη. Importantly, deletion of RAD30 sensitized the strain to amphotericin B; but its presence resulted in azole drug tolerance only in DNA damaging conditions. We suggest that the roles of CaPolη in genome stability and genotoxins induced filamentation are due to its TLS activities; whereas its TLS independent functions play a vital role in serum induced morphogenesis and amphotericin B resistance.
Collapse
Affiliation(s)
- Kodavati Manohar
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Doureradjou Peroumal
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| |
Collapse
|
34
|
Zimmerman SM, Kon Y, Hauke AC, Ruiz BY, Fields S, Phizicky EM. Conditional accumulation of toxic tRNAs to cause amino acid misincorporation. Nucleic Acids Res 2018; 46:7831-7843. [PMID: 30007351 PMCID: PMC6125640 DOI: 10.1093/nar/gky623] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 06/22/2018] [Accepted: 07/01/2018] [Indexed: 12/16/2022] Open
Abstract
To develop a system for conditional amino acid misincorporation, we engineered tRNAs in the yeast Saccharomyces cerevisiae to be substrates of the rapid tRNA decay (RTD) pathway, such that they accumulate when RTD is turned off. We used this system to test the effects on growth of a library of tRNASer variants with all possible anticodons, and show that many are lethal when RTD is inhibited and the tRNA accumulates. Using mass spectrometry, we measured serine misincorporation in yeast containing each of six tRNA variants, and for five of them identified hundreds of peptides with serine substitutions at the targeted amino acid sites. Unexpectedly, we found that there is not a simple correlation between toxicity and the level of serine misincorporation; in particular, high levels of serine misincorporation can occur at cysteine residues without obvious growth defects. We also showed that toxic tRNAs can be used as a tool to identify sequence variants that reduce tRNA function. Finally, we generalized this method to another tRNA species, and generated conditionally toxic tRNATyr variants in a similar manner. This method should facilitate the study of tRNA biology and provide a tool to probe the effects of amino acid misincorporation on cellular physiology.
Collapse
Affiliation(s)
| | - Yoshiko Kon
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Alayna C Hauke
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Bianca Y Ruiz
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Stanley Fields
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY 14642, USA
| |
Collapse
|
35
|
Legrand M, Bachellier-Bassi S, Lee KK, Chaudhari Y, Tournu H, Arbogast L, Boyer H, Chauvel M, Cabral V, Maufrais C, Nesseir A, Maslanka I, Permal E, Rossignol T, Walker LA, Zeidler U, Znaidi S, Schoeters F, Majgier C, Julien RA, Ma L, Tichit M, Bouchier C, Van Dijck P, Munro CA, d’Enfert C. Generating genomic platforms to study Candida albicans pathogenesis. Nucleic Acids Res 2018; 46:6935-6949. [PMID: 29982705 PMCID: PMC6101633 DOI: 10.1093/nar/gky594] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/19/2018] [Accepted: 06/25/2018] [Indexed: 12/19/2022] Open
Abstract
The advent of the genomic era has made elucidating gene function on a large scale a pressing challenge. ORFeome collections, whereby almost all ORFs of a given species are cloned and can be subsequently leveraged in multiple functional genomic approaches, represent valuable resources toward this endeavor. Here we provide novel, genome-scale tools for the study of Candida albicans, a commensal yeast that is also responsible for frequent superficial and disseminated infections in humans. We have generated an ORFeome collection composed of 5099 ORFs cloned in a Gateway™ donor vector, representing 83% of the currently annotated coding sequences of C. albicans. Sequencing data of the cloned ORFs are available in the CandidaOrfDB database at http://candidaorfeome.eu. We also engineered 49 expression vectors with a choice of promoters, tags and selection markers and demonstrated their applicability to the study of target ORFs transferred from the C. albicans ORFeome. In addition, the use of the ORFeome in the detection of protein-protein interaction was demonstrated. Mating-compatible strains as well as Gateway™-compatible two-hybrid vectors were engineered, validated and used in a proof of concept experiment. These unique and valuable resources should greatly facilitate future functional studies in C. albicans and the elucidation of mechanisms that underlie its pathogenicity.
Collapse
Affiliation(s)
- Mélanie Legrand
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Sophie Bachellier-Bassi
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Keunsook K Lee
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Yogesh Chaudhari
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Hélène Tournu
- VIB-KU Leuven Center for Microbiology, Leuven 3001, Belgium
- Laboratory of Molecular Cell Biology, KU Leuven, Leuven 3001, Belgium
| | - Laurence Arbogast
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Hélène Boyer
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Murielle Chauvel
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Vitor Cabral
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
- Univ. Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris 75015, France
| | - Corinne Maufrais
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
- Institut Pasteur-Bioinformatics and Biostatistics Hub-C3BI, USR 3756 IP CNRS-Paris 75015, France
| | - Audrey Nesseir
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
- Univ. Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris 75015, France
| | - Irena Maslanka
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Emmanuelle Permal
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Tristan Rossignol
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Louise A Walker
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Ute Zeidler
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Sadri Znaidi
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| | - Floris Schoeters
- VIB-KU Leuven Center for Microbiology, Leuven 3001, Belgium
- Laboratory of Molecular Cell Biology, KU Leuven, Leuven 3001, Belgium
| | - Charlotte Majgier
- Modul-Bio, Parc Scientifique Luminy Biotech II, Marseille 13009, France
| | - Renaud A Julien
- Modul-Bio, Parc Scientifique Luminy Biotech II, Marseille 13009, France
| | - Laurence Ma
- Institut Pasteur-Biomics Pole-CITECH-Paris 75015, France
| | - Magali Tichit
- Institut Pasteur-Biomics Pole-CITECH-Paris 75015, France
| | | | - Patrick Van Dijck
- VIB-KU Leuven Center for Microbiology, Leuven 3001, Belgium
- Laboratory of Molecular Cell Biology, KU Leuven, Leuven 3001, Belgium
| | - Carol A Munro
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Christophe d’Enfert
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris 75015, France
| |
Collapse
|
36
|
Abstract
The pool of transfer RNA (tRNA) molecules in cells allows the ribosome to decode genetic information. This repertoire of molecular decoders is positioned in the crossroad of the genome, the transcriptome, and the proteome. Omics and systems biology now allow scientists to explore the entire repertoire of tRNAs of many organisms, revealing basic exciting biology. The tRNA gene set of hundreds of species is now characterized, in addition to the tRNA genes of organelles and viruses. Genes encoding tRNAs for certain anticodon types appear in dozens of copies in a genome, while others are universally absent from any genome. Transcriptome measurement of tRNAs is challenging, but in recent years new technologies have allowed researchers to determine the dynamic expression patterns of tRNAs. These advances reveal that availability of ready-to-translate tRNA molecules is highly controlled by several transcriptional and posttranscriptional regulatory processes. This regulation shapes the proteome according to the cellular state. The tRNA pool profoundly impacts many aspects of cellular and organismal life, including protein expression level, translation accuracy, adequacy of folding, and even mRNA stability. As a result, the shape of the tRNA pool affects organismal health and may participate in causing conditions such as cancer and neurological conditions.
Collapse
Affiliation(s)
- Roni Rak
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
| | - Orna Dahan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
| | - Yitzhak Pilpel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
| |
Collapse
|
37
|
Mielich K, Shtifman-Segal E, Golz JC, Zeng G, Wang Y, Berman J, Kunze R. Maize Transposable Elements Ac/ Ds as Insertion Mutagenesis Tools in Candida albicans. G3 (BETHESDA, MD.) 2018; 8:1139-1145. [PMID: 29378819 PMCID: PMC5873905 DOI: 10.1534/g3.117.300388] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/26/2018] [Indexed: 12/23/2022]
Abstract
In nonmodel systems, genetic research is often limited by the lack of techniques for the generation and identification of gene mutations. One approach to overcome this bottleneck is the application of transposons for gene tagging. We have established a two-element transposon tagging system, based on the transposable elements Activator (Ac)/Dissociation (Ds) from maize, for in vivo insertion mutagenesis in the fungal human pathogen Candida albicans A nonautonomous Ds transposon carrying a selectable marker was constructed into the ADE2 promoter on chromosome 3 and a codon usage-adapted Ac transposase gene was inserted into the neutral NEUT5L locus on chromosome 5. In C. albicans cells expressing the transposase, the Ds element efficiently excised and reintegrated elsewhere in the genome, which makes the Ac/Ds transposons promising tools for saturating insertion mutagenesis in clinical strains of C. albicans.
Collapse
Affiliation(s)
- Kevin Mielich
- Institute of Biology, Dahlem Centre of Plant Sciences, Free University pf Berlin, 14195, Germany
| | - Ella Shtifman-Segal
- Department of Molecular Microbiology and Biotechnology, George Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Julia C Golz
- Institute of Biology, Dahlem Centre of Plant Sciences, Free University pf Berlin, 14195, Germany
| | - Guisheng Zeng
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, 138673, Singapore
| | - Yue Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, 138673, Singapore
| | - Judith Berman
- Department of Molecular Microbiology and Biotechnology, George Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Reinhard Kunze
- Institute of Biology, Dahlem Centre of Plant Sciences, Free University pf Berlin, 14195, Germany
| |
Collapse
|
38
|
A CTG Clade Candida Yeast Genetically Engineered for the Genotype-Phenotype Characterization of Azole Antifungal Resistance in Human-Pathogenic Yeasts. Antimicrob Agents Chemother 2017; 62:AAC.01483-17. [PMID: 29038279 DOI: 10.1128/aac.01483-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/12/2017] [Indexed: 11/20/2022] Open
Abstract
A strain of the opportunistic pathogenic yeast Candida lusitaniae was genetically modified for use as a cellular model for assessing by allele replacement the impact of lanosterol C14α-demethylase ERG11 mutations on azole resistance. Candida lusitaniae was chosen because it is susceptible to azole antifungals, it belongs to the CTG clade of yeast, which includes most of the Candida species pathogenic for humans, and it is haploid and easily amenable to genetic transformation and molecular modeling. In this work, allelic replacement is targeted at the ERG11 locus by the reconstitution of a functional auxotrophic marker in the 3' intergenic region of ERG11 Homologous and heterologous ERG11 alleles are expressed from the resident ERG11 promoter of C. lusitaniae, allowing accurate comparison of the phenotypic change in azole susceptibility. As a proof of concept, we successfully expressed in C. lusitaniae different ERG11 alleles, either bearing or not bearing mutations retrieved from a clinical context, from two phylogenetically distant yeasts, C. albicans and Kluyveromyces marxianusCandida lusitaniae constitutes a high-fidelity expression system, giving specific Erg11p-dependent fluconazole MICs very close to those observed with the ERG11 donor strain. This work led us to characterize the phenotypic effect of two kinds of mutation: mutation conferring decreased fluconazole susceptibility in a species-specific manner and mutation conferring fluconazole resistance in several yeast species. In particular, a missense mutation affecting amino acid K143 of Erg11p in Candida species, and the equivalent position K151 in K. marxianus, plays a critical role in fluconazole resistance.
Collapse
|
39
|
A Bimolecular Fluorescence Complementation Tool for Identification of Protein-Protein Interactions in Candida albicans. G3-GENES GENOMES GENETICS 2017; 7:3509-3520. [PMID: 28860184 PMCID: PMC5633398 DOI: 10.1534/g3.117.300149] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Investigation of protein-protein interactions (PPI) in Candida albicans is essential for understanding the regulation of the signal transduction network that triggers its pathogenic lifestyle. Unique features of C. albicans, such as its alternative codon usage and incomplete meiosis, have enforced the optimization of standard genetic methods as well as development of novel approaches. Since the existing methods for detection of PPI are limited for direct visualization of the interacting complex in vivo, we have established a bimolecular fluorescence complementation (BiFC) assay in C. albicans, a powerful technique for studying PPI. We have developed an optimized set of plasmids that allows for N- and C-terminal tagging of proteins with split yeast-enhanced monomeric Venus fragments, so that all eight combinations of fusion orientations can be analyzed. With the use of our BiFC assay we demonstrate three interaction complexes in vivo, which were also confirmed by two-hybrid analysis. Our Candida-optimized BiFC assay represents a useful molecular tool for PPI studies and shows great promise in expanding our knowledge of molecular mechanisms of protein functions.
Collapse
|
40
|
Affiliation(s)
- Kenneth H. Wolfe
- School of Medicine, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Geraldine Butler
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| |
Collapse
|
41
|
Gow NAR, Yadav B. Microbe Profile: Candida albicans: a shape-changing, opportunistic pathogenic fungus of humans. MICROBIOLOGY-SGM 2017; 163:1145-1147. [PMID: 28809155 DOI: 10.1099/mic.0.000499] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Candida albicans is normally a harmless commensal of human beings, but it can cause superficial infections of the mucosa (oral/vaginal thrush) in healthy individuals and (rarely) infections of the skin or nails. It can also become invasive, causing life-threatening systemic and bloodstream infections in immunocompromised hosts, where the mortality rate can be as high as 50 %. It is the most common cause of serious fungal infection and is a common cause of nosocomial infections in hospitals. Some strains have been recognized that are resistant to azoles or echinocandins, which are the first-line antifungals for treatment of C. albicans infections.
Collapse
Affiliation(s)
- Neil A R Gow
- The Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Science and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB252ZD, UK
| | - Bhawna Yadav
- The Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Science and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB252ZD, UK
| |
Collapse
|
42
|
Lombardi L, Turner SA, Zhao F, Butler G. Gene editing in clinical isolates of Candida parapsilosis using CRISPR/Cas9. Sci Rep 2017; 7:8051. [PMID: 28808289 PMCID: PMC5556056 DOI: 10.1038/s41598-017-08500-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/10/2017] [Indexed: 01/04/2023] Open
Abstract
Candida parapsilosis is one of the most common causes of candidiasis, particularly in the very young and the very old. Studies of gene function are limited by the lack of a sexual cycle, the diploid genome, and a paucity of molecular tools. We describe here the development of a plasmid-based CRISPR-Cas9 system for gene editing in C. parapsilosis. A major advantage of the system is that it can be used in any genetic background, which we showed by editing genes in 20 different isolates. Gene editing is carried out in a single transformation step. The CAS9 gene is expressed only when the plasmid is present, and it can be removed easily from transformed strains. There is theoretically no limit to the number of genes that can be edited in any strain. Gene editing is increased by homology-directed repair in the presence of a repair template. Editing by non-homologous end joining (NHEJ) also occurs in some genetic backgrounds. Finally, we used the system to introduce unique tags at edited sites.
Collapse
Affiliation(s)
- Lisa Lombardi
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Siobhán A Turner
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Fang Zhao
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Geraldine Butler
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
| |
Collapse
|
43
|
Abstract
We focus this article on turning a biofilm inside out. The "inside" of the biofilm comprises the individual biofilm-related phenotypes, their environmental drivers and genetic determinants, and the coordination of gene functions through transcriptional regulators. Investigators have viewed the inside of the biofilm through diverse approaches, and this article will attempt to capture the essence of many. The ultimate goal is to connect the inside to the "outside," which we view as biofilm structure, development, pharmacological attributes, and medical impact.
Collapse
|
44
|
Dujon BA, Louis EJ. Genome Diversity and Evolution in the Budding Yeasts (Saccharomycotina). Genetics 2017; 206:717-750. [PMID: 28592505 PMCID: PMC5499181 DOI: 10.1534/genetics.116.199216] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 04/03/2017] [Indexed: 12/15/2022] Open
Abstract
Considerable progress in our understanding of yeast genomes and their evolution has been made over the last decade with the sequencing, analysis, and comparisons of numerous species, strains, or isolates of diverse origins. The role played by yeasts in natural environments as well as in artificial manufactures, combined with the importance of some species as model experimental systems sustained this effort. At the same time, their enormous evolutionary diversity (there are yeast species in every subphylum of Dikarya) sparked curiosity but necessitated further efforts to obtain appropriate reference genomes. Today, yeast genomes have been very informative about basic mechanisms of evolution, speciation, hybridization, domestication, as well as about the molecular machineries underlying them. They are also irreplaceable to investigate in detail the complex relationship between genotypes and phenotypes with both theoretical and practical implications. This review examines these questions at two distinct levels offered by the broad evolutionary range of yeasts: inside the best-studied Saccharomyces species complex, and across the entire and diversified subphylum of Saccharomycotina. While obviously revealing evolutionary histories at different scales, data converge to a remarkably coherent picture in which one can estimate the relative importance of intrinsic genome dynamics, including gene birth and loss, vs. horizontal genetic accidents in the making of populations. The facility with which novel yeast genomes can now be studied, combined with the already numerous available reference genomes, offer privileged perspectives to further examine these fundamental biological questions using yeasts both as eukaryotic models and as fungi of practical importance.
Collapse
Affiliation(s)
- Bernard A Dujon
- Department Genomes and Genetics, Institut Pasteur, Centre National de la Recherche Scientifique UMR3525, 75724-CEDEX15 Paris, France
- Université Pierre et Marie Curie UFR927, 75005 Paris, France
| | - Edward J Louis
- Centre for Genetic Architecture of Complex Traits, University of Leicester, LE1 7RH, United Kingdom
- Department of Genetics, University of Leicester, LE1 7RH, United Kingdom
| |
Collapse
|
45
|
Abstract
We focus this article on turning a biofilm inside out. The "inside" of the biofilm comprises the individual biofilm-related phenotypes, their environmental drivers and genetic determinants, and the coordination of gene functions through transcriptional regulators. Investigators have viewed the inside of the biofilm through diverse approaches, and this article will attempt to capture the essence of many. The ultimate goal is to connect the inside to the "outside," which we view as biofilm structure, development, pharmacological attributes, and medical impact.
Collapse
Affiliation(s)
- Katherine Lagree
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Aaron P Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| |
Collapse
|
46
|
Mistranslation: from adaptations to applications. Biochim Biophys Acta Gen Subj 2017; 1861:3070-3080. [PMID: 28153753 DOI: 10.1016/j.bbagen.2017.01.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND The conservation of the genetic code indicates that there was a single origin, but like all genetic material, the cell's interpretation of the code is subject to evolutionary pressure. Single nucleotide variations in tRNA sequences can modulate codon assignments by altering codon-anticodon pairing or tRNA charging. Either can increase translation errors and even change the code. The frozen accident hypothesis argued that changes to the code would destabilize the proteome and reduce fitness. In studies of model organisms, mistranslation often acts as an adaptive response. These studies reveal evolutionary conserved mechanisms to maintain proteostasis even during high rates of mistranslation. SCOPE OF REVIEW This review discusses the evolutionary basis of altered genetic codes, how mistranslation is identified, and how deviations to the genetic code are exploited. We revisit early discoveries of genetic code deviations and provide examples of adaptive mistranslation events in nature. Lastly, we highlight innovations in synthetic biology to expand the genetic code. MAJOR CONCLUSIONS The genetic code is still evolving. Mistranslation increases proteomic diversity that enables cells to survive stress conditions or suppress a deleterious allele. Genetic code variants have been identified by genome and metagenome sequence analyses, suppressor genetics, and biochemical characterization. GENERAL SIGNIFICANCE Understanding the mechanisms of translation and genetic code deviations enables the design of new codes to produce novel proteins. Engineering the translation machinery and expanding the genetic code to incorporate non-canonical amino acids are valuable tools in synthetic biology that are impacting biomedical research. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
Collapse
|
47
|
Multiple Origins of the Pathogenic Yeast Candida orthopsilosis by Separate Hybridizations between Two Parental Species. PLoS Genet 2016; 12:e1006404. [PMID: 27806045 PMCID: PMC5091853 DOI: 10.1371/journal.pgen.1006404] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 10/04/2016] [Indexed: 01/02/2023] Open
Abstract
Mating between different species produces hybrids that are usually asexual and stuck as diploids, but can also lead to the formation of new species. Here, we report the genome sequences of 27 isolates of the pathogenic yeast Candida orthopsilosis. We find that most isolates are diploid hybrids, products of mating between two unknown parental species (A and B) that are 5% divergent in sequence. Isolates vary greatly in the extent of homogenization between A and B, making their genomes a mosaic of highly heterozygous regions interspersed with homozygous regions. Separate phylogenetic analyses of SNPs in the A- and B-derived portions of the genome produces almost identical trees of the isolates with four major clades. However, the presence of two mutually exclusive genotype combinations at the mating type locus, and recombinant mitochondrial genomes diagnostic of inter-clade mating, shows that the species C. orthopsilosis does not have a single evolutionary origin but was created at least four times by separate interspecies hybridizations between parents A and B. Older hybrids have lost more heterozygosity. We also identify two isolates with homozygous genomes derived exclusively from parent A, which are pure non-hybrid strains. The parallel emergence of the same hybrid species from multiple independent hybridization events is common in plant evolution, but is much less documented in pathogenic fungi. The genus Candida is one of the leading causes of fungal morbidity in humans. Many pathogenic Candida species are diploid, and do not have have a full sexual cycle. The evolutionary origin of Candida orthopsilosis is unclear. Here, we use whole genome sequencing of 27 C. orthopsilosis isolates from around the world to show that C. orthopsilosis arose from hybridization (or mating) of two distinct parental species. Unusually, the hybridization event did not occur only once; we identify at least four events, and we suggest that hybridization is ongoing. The “species” C. orthopsilosis therefore does not have one single origin. We have identified one of the parental lineages involved, but the other remains elusive. Our results suggest that inter-species hybridization has an evolutionary advantage. However, unlike in plant pathogens, it does not appear to result in increased virulence of C. orthopsilosis.
Collapse
|
48
|
Donovan PD, Schröder MS, Higgins DG, Butler G. Identification of Non-Coding RNAs in the Candida parapsilosis Species Group. PLoS One 2016; 11:e0163235. [PMID: 27658249 PMCID: PMC5033589 DOI: 10.1371/journal.pone.0163235] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/06/2016] [Indexed: 01/08/2023] Open
Abstract
The Candida CTG clade is a monophyletic group of fungal species that translates CTG as serine, and includes the pathogens Candida albicans and Candida parapsilosis. Research has typically focused on identifying protein-coding genes in these species. Here, we use bioinformatic and experimental approaches to annotate known classes of non-coding RNAs in three CTG-clade species, Candida parapsilosis, Candida orthopsilosis and Lodderomyces elongisporus. We also update the annotation of ncRNAs in the C. albicans genome. The majority of ncRNAs identified were snoRNAs. Approximately 50% of snoRNAs (including most of the C/D box class) are encoded in introns. Most are within mono- and polycistronic transcripts with no protein coding potential. Five polycistronic clusters of snoRNAs are highly conserved in fungi. In polycistronic regions, splicing occurs via the classical pathway, as well as by nested and recursive splicing. We identified spliceosomal small nuclear RNAs, the telomerase RNA component, signal recognition particle, RNase P RNA component and the related RNase MRP RNA component in all three genomes. Stem loop IV of the U2 spliceosomal RNA and the associated binding proteins were lost from the ancestor of C. parapsilosis and C. orthopsilosis, following the divergence from L. elongisporus. The RNA component of the MRP is longer in C. parapsilosis, C. orthopsilosis and L. elongisporus than in S. cerevisiae, but is substantially shorter than in C. albicans.
Collapse
Affiliation(s)
- Paul D. Donovan
- School of Biomedical and Biomolecular Science and UCD Conway Institute of Biomolecular and Biomedical Research, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Markus S. Schröder
- School of Biomedical and Biomolecular Science and UCD Conway Institute of Biomolecular and Biomedical Research, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Desmond G. Higgins
- School of Medicine and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Geraldine Butler
- School of Biomedical and Biomolecular Science and UCD Conway Institute of Biomolecular and Biomedical Research, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
- * E-mail:
| |
Collapse
|
49
|
Stress sensitivity of a fission yeast strain lacking histidine kinases is rescued by the ectopic expression of Chk1 from Candida albicans. Curr Genet 2016; 63:343-357. [PMID: 27613427 PMCID: PMC5383687 DOI: 10.1007/s00294-016-0644-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 01/07/2023]
Abstract
The development of new drugs against the pathogenic yeast Candida albicans is compelling and the evolution of relevant bioassays is important to achieve this goal. Promising drug targets are proteins that lack human counterparts which are true for the His-to-Asp phosphorelay signal transduction systems, important for stress sensing in bacteria, fungi, and plants. In the pathogenic yeast, Candida albicans, the CaChk1 histidine kinase is a trigger of the pathway that leads to a switch from yeast to hyphal growth necessary for invasion. Intriguingly, the model yeast Schizosaccharomyces pombe has a similar phosphorelay system, with three histidine kinases named Mak1, Mak2, and Mak3, which are important for the prevention of aberrant mating and sporulation on rich media. This study uncovered distinct functions for the three histidine kinases; Mak1 alone or Mak2 and Mak3 together were sufficient for the repression of the meiotic cycle when nutrients were available. Moreover, strains lacking histidine kinase genes were sensitive to various types of stress conditions in an auxotrophic strain background, while the stress sensitivity was lost in prototrophic strains. Finally, the stress sensitivity of a S. pombe strain that lacks endogenous histidine kinases could be complemented by the ectopic expression of the CaChk1 histidine kinase from C. albicans. This finding opens up for the possibility to perform a drug screen with a biological read-out in S. pombe to find inhibitors of CaChk1.
Collapse
|
50
|
Swart EC, Serra V, Petroni G, Nowacki M. Genetic Codes with No Dedicated Stop Codon: Context-Dependent Translation Termination. Cell 2016; 166:691-702. [PMID: 27426948 PMCID: PMC4967479 DOI: 10.1016/j.cell.2016.06.020] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 04/19/2016] [Accepted: 06/06/2016] [Indexed: 01/13/2023]
Abstract
The prevailing view of the nuclear genetic code is that it is largely frozen and unambiguous. Flexibility in the nuclear genetic code has been demonstrated in ciliates that reassign standard stop codons to amino acids, resulting in seven variant genetic codes, including three previously undescribed ones reported here. Surprisingly, in two of these species, we find efficient translation of all 64 codons as standard amino acids and recognition of either one or all three stop codons. How, therefore, does the translation machinery interpret a “stop” codon? We provide evidence, based on ribosomal profiling and “stop” codon depletion shortly before coding sequence ends, that mRNA 3′ ends may contribute to distinguishing stop from sense in a context-dependent manner. We further propose that such context-dependent termination/readthrough suppression near transcript ends enables genetic code evolution. Alternative nuclear genetic codes continue to be discovered in ciliates Genetic codes with stops and all their codons encoding standard amino acids exist Transcript ends may distinguish stop codons as such in ambiguous genetic codes The ability to resolve genetic code ambiguity may enable genetic code evolution
Collapse
Affiliation(s)
| | - Valentina Serra
- Department of Biology, University of Pisa, Pisa 56126, Italy
| | - Giulio Petroni
- Department of Biology, University of Pisa, Pisa 56126, Italy
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland.
| |
Collapse
|