scholarly journals Systematic Analysis of Functionally Related Gene Clusters in the Opportunistic Pathogen, Candida albicans

2021 ◽  
Vol 9 (2) ◽  
pp. 276
Author(s):  
Sarah Asfare ◽  
Reem Eldabagh ◽  
Khizar Siddiqui ◽  
Bharvi Patel ◽  
Diellza Kaba ◽  
...  
Keyword(s):  
Gene Expression ◽  
Candida Albicans ◽  
Gene Families ◽  
Gene Clusters ◽  
Opportunistic Pathogen ◽  
Systematic Analysis ◽  
Genomic Arrangement ◽  
A Genome ◽  
Opportunistic Human Pathogen ◽  
Organismal Development

The proper balance of gene expression is essential for cellular health, organismal development, and maintaining homeostasis. In response to complex internal and external signals, the cell needs to modulate gene expression to maintain proteostasis and establish cellular identity within its niche. On a genome level, single-celled prokaryotic microbes display clustering of co-expressed genes that are regulated as a polycistronic RNA. This phenomenon is largely absent from eukaryotic microbes, although there is extensive clustering of co-expressed genes as functional pairs spread throughout the genome in Saccharomyces cerevisiae. While initial analysis demonstrated conservation of clustering in divergent fungal lineages, a comprehensive analysis has yet to be performed. Here we report on the prevalence, conservation, and significance of the functional clustering of co-regulated genes within the opportunistic human pathogen, Candida albicans. Our analysis reveals that there is extensive clustering within this organism—although the identity of the gene pairs is unique compared with those found in S. cerevisiae—indicating that this genomic arrangement evolved after these microbes diverged evolutionarily, rather than being the result of an ancestral arrangement. We report a clustered arrangement in gene families that participate in diverse molecular functions and are not the result of a divergent orientation with a shared promoter. This arrangement coordinates the transcription of the clustered genes to their neighboring genes, with the clusters congregating to genomic loci that are conducive to transcriptional regulation at a distance.

scholarly journals Genome-Wide Analysis of Basic Helix-Loop-Helix (bHLH) TFs in Sea Buckthorn (Hippophae rhamnoides)

2020 ◽  
Author(s):  
Songfeng Diao ◽  
Hong Liu ◽  
Zhongrui Lv ◽  
Caiyun He ◽  
Aiguo Duan ◽  
...  
Keyword(s):  
Gene Family ◽  
Stress Responses ◽  
Gene Families ◽  
Sea Buckthorn ◽  
Bhlh Transcription Factor ◽  
Systematic Analysis ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Genome Wide ◽  
A Genome

Abstract Background The basic helix-loop-helix (bHLH) transcription factor gene family is one of the largest gene families and extensively involved in plant growth, organ development, and stress responses. However, limited studies are available on the gene family in sea buckthorn. Results In this study, we focused on 144 HrbHLH genes, exploring their DNA and protein sequences and physicochemical properties. According to their protein sequence similarities, we classified the genes into 15 groups with specific motif structures. In order to explore their expressions, we performed gene expression profiling using RNA-Seq and identified 108 HrbHLH genes that expressed in five sea buckthorn tissue, including root nodule, root, leaf, stem and fruit. Furthermore, we found 11 increased expressed HrbHLH genes during sea buckthorn fruit development. We validated the expression pattern of HrbHLH genes using reverse transcription quantitative real-time PCR. Conclusions This study lays the foundation for future studies on gene cloning, transgenes, and biological mechanisms. We performed a genome-wide, systematic analysis of bHLH proteins in sea buckthorn. This comprehensive analysis provides a useful resource that enables further investigation of the physiological roles and molecular functions of the HrbHLH TFs.

scholarly journals Cell Biology of the Trypanosome Genome

2010 ◽  
Vol 74 (4) ◽  
pp. 552-569 ◽  
Author(s):  
Jan-Peter Daniels ◽  
Keith Gull ◽  
Bill Wickstead
Keyword(s):  
Gene Expression ◽  
Cell Biology ◽  
Nuclear Organization ◽  
Nuclear Architecture ◽  
Gene Clusters ◽  
Model Organisms ◽  
Protein Coding ◽  
African Trypanosomes ◽  
Protein Coding Genes ◽  
A Genome

SUMMARY Trypanosomes are a group of protozoan eukaryotes, many of which are major parasites of humans and livestock. The genomes of trypanosomes and their modes of gene expression differ in several important aspects from those of other eukaryotic model organisms. Protein-coding genes are organized in large directional gene clusters on a genome-wide scale, and their polycistronic transcription is not generally regulated at initiation. Transcripts from these polycistrons are processed by global trans-splicing of pre-mRNA. Furthermore, in African trypanosomes, some protein-coding genes are transcribed by a multifunctional RNA polymerase I from a specialized extranucleolar compartment. The primary DNA sequence of the trypanosome genomes and their cellular organization have usually been treated as separate entities. However, it is becoming increasingly clear that in order to understand how a genome functions in a living cell, we will need to unravel how the one-dimensional genomic sequence and its trans-acting factors are arranged in the three-dimensional space of the eukaryotic nucleus. Understanding this cell biology of the genome will be crucial if we are to elucidate the genetic control mechanisms of parasitism. Here, we integrate the concepts of nuclear architecture, deduced largely from studies of yeast and mammalian nuclei, with recent developments in our knowledge of the trypanosome genome, gene expression, and nuclear organization. We also compare this nuclear organization to those in other systems in order to shed light on the evolution of nuclear architecture in eukaryotes.

scholarly journals Regulation of Candida albicans Hyphal Morphogenesis by Endogenous Signals

2019 ◽  
Vol 5 (1) ◽  
pp. 21 ◽  
Author(s):  
Daniel Kornitzer
Keyword(s):  
Gene Expression ◽  
Candida Albicans ◽  
Cell Cycle Progression ◽  
Hyphal Growth ◽  
Specific Gene ◽  
Hyphal Morphogenesis ◽  
Recent Developments ◽  
Opportunistic Human Pathogen ◽  
External Stimuli ◽  
Transcription Program

Candida albicans is a human commensal fungus that is able to assume several morphologies, including yeast, hyphal, and pseudohyphal. Under a range of conditions, C. albicans performs a regulated switch to the filamentous morphology, characterized by the emergence of a germ tube from the yeast cell, followed by a mold-like growth of branching hyphae. This transition from yeast to hyphal growth has attracted particular attention, as it has been linked to the virulence of C. albicans as an opportunistic human pathogen. Signal transduction pathways that mediate the induction of the hyphal transcription program upon the imposition of external stimuli have been extensively investigated. However, the hyphal morphogenesis transcription program can also be induced by internal cellular signals, such as inhibition of cell cycle progression, and conversely, the inhibition of hyphal extension can repress hyphal-specific gene expression, suggesting that endogenous cellular signals are able to modulate hyphal gene expression as well. Here we review recent developments in the regulation of the hyphal morphogenesis of C. albicans, with emphasis on endogenous morphogenetic signals.

scholarly journals Adaptations of Candida albicans for Growth in the Mammalian Intestinal Tract

2010 ◽  
Vol 9 (7) ◽  
pp. 1075-1086 ◽  
Author(s):  
Ari Rosenbach ◽  
Daniel Dignard ◽  
Jessica V. Pierce ◽  
Malcolm Whiteway ◽  
Carol A. Kumamoto
Keyword(s):  
Gene Expression ◽  
Candida Albicans ◽  
Intestinal Tract ◽  
Opportunistic Pathogen ◽  
Exponential Phase ◽  
Host Tissue ◽  
Transcription Profile ◽  
Intestinal Colonization ◽  
Content Type ◽  
Successful Establishment

ABSTRACT Although the fungus Candida albicans is a commensal colonizer of humans, the organism is also an important opportunistic pathogen. Most infections caused by C. albicans arise from organisms that were previously colonizing the host as commensals, and therefore successful establishment of colonization is a prerequisite for pathogenicity. To elucidate fungal activities that promote colonization, an analysis of the transcription profile of C. albicans cells recovered from the intestinal tracts of mice was performed. The results showed that within the C. albicans colonizing population, cells expressed genes characteristic of the laboratory-grown exponential phase and genes characteristic of post-exponential-phase cells. Thus, gene expression both promoted the ability to grow rapidly (a characteristic of exponential-phase cells) and enhanced the ability to resist stresses (a characteristic of post-exponential-phase cells). Similarities in gene expression in commensal colonizing cells and cells invading host tissue during disease were found, showing that C. albicans cells adopt a particular cell surface when growing within a host in both situations. In addition, transcription factors Cph2p and Tec1p were shown to regulate C. albicans gene expression during intestinal colonization.

scholarly journals The genome of the butternut canker pathogen, Ophiognomonia clavigignenti-juglandacearum shows an elevated number of genes associated with secondary metabolism and protection from host resistance responses

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9265
Author(s):  
Guangxi Wu ◽  
Taruna A. Schuelke ◽  
Gloria Iriarte ◽  
Kirk Broders
Keyword(s):  
Secondary Metabolism ◽  
Pathogenic Fungus ◽  
Gene Families ◽  
Gene Clusters ◽  
Large Numbers ◽  
Genome Wide ◽  
A Genome ◽  
Number Of Genes ◽  
Hardwood Tree ◽  
Branch Dieback

Ophiognomonia clavigignenti-juglandacearum (Oc-j) is a plant pathogenic fungus that causes canker and branch dieback diseases in the hardwood tree butternut, Juglans cinerea. Oc-j is a member of the order of Diaporthales, which includes many other plant pathogenic species, several of which also infect hardwood tree species. In this study, we sequenced the genome of Oc-j and achieved a high-quality assembly and delineated its phylogeny within the Diaporthales order using a genome-wide multi-gene approach. We also further examined multiple gene families that might be involved in plant pathogenicity and degradation of complex biomass, which are relevant to a pathogenic life-style in a tree host. We found that the Oc-j genome contains a greater number of genes in these gene families compared to other species in the Diaporthales. These gene families include secreted CAZymes, kinases, cytochrome P450, efflux pumps, and secondary metabolism gene clusters. The large numbers of these genes provide Oc-j with an arsenal to cope with the specific ecological niche as a pathogen of the butternut tree.

scholarly journals Regulation of Secondary Metabolism by the Velvet Complex Is Temperature-Responsive in Aspergillus

2016 ◽  
Vol 6 (12) ◽  
pp. 4023-4033 ◽  
Author(s):  
Abigail L Lind ◽  
Timothy D Smith ◽  
Timothy Saterlee ◽  
Ana M Calvo ◽  
Antonis Rokas
Keyword(s):  
Gene Expression ◽  
Secondary Metabolism ◽  
Global Gene Expression ◽  
Gene Clusters ◽  
Temperature Dependent ◽  
Transcription Profiles ◽  
Fungal Secondary Metabolism ◽  
Opportunistic Human Pathogen ◽  
Velvet Complex

Abstract Sensing and responding to environmental cues is critical to the lifestyle of filamentous fungi. How environmental variation influences fungi to produce a wide diversity of ecologically important secondary metabolites (SMs) is not well understood. To address this question, we first examined changes in global gene expression of the opportunistic human pathogen, Aspergillus fumigatus, after exposure to different temperature conditions. We found that 11 of the 37 SM gene clusters in A. fumigatus were expressed at higher levels at 30° than at 37°. We next investigated the role of the light-responsive Velvet complex in environment-dependent gene expression by examining temperature-dependent transcription profiles in the absence of two key members of the Velvet protein complex, VeA and LaeA. We found that the 11 temperature-regulated SM gene clusters required VeA at 37° and LaeA at both 30 and 37° for wild-type levels of expression. Interestingly, four SM gene clusters were regulated by VeA at 37° but not at 30°, and two additional ones were regulated by VeA at both temperatures but were substantially less so at 30°, indicating that the role of VeA and, more generally of the Velvet complex, in the regulation of certain SM gene clusters is temperature-dependent. Our findings support the hypothesis that fungal secondary metabolism is regulated by an intertwined network of transcriptional regulators responsive to multiple environmental factors.

scholarly journals The genome of the butternut canker pathogen, Ophiognomonia clavigignenti-juglandacearum shows an elevated number of genes associated with secondary metabolism and protection from host resistance responses in comparison with other members of the Diaporthales

2019 ◽  
Author(s):  
Guangxi Wu ◽  
Taruna A. Schuelke ◽  
Kirk Broders
Keyword(s):  
Secondary Metabolism ◽  
Pathogenic Fungus ◽  
Gene Families ◽  
Gene Clusters ◽  
Large Numbers ◽  
Genome Wide ◽  
A Genome ◽  
Number Of Genes ◽  
Hardwood Tree ◽  
Branch Dieback

AbstractOphiognomonia clavigignentijuglandacearum (Oc-j) is a plant pathogenic fungus that causes canker and branch dieback diseases in the hardwood tree butternut, Juglans cinerea. Oc-j is a member of the order of Diaporthales, which includes many other plant pathogenic species, several of which also infect hardwood tree species. In this study, we sequenced the genome of Oc-j and achieved a high-quality assembly and delineated the phylogeny of Oc-j within the Diaporthales order using a genome-wide multi-gene approach. We also further examined multiple gene families that might be involved in plant pathogenicity and degradation of complex biomass, which are relevant to a pathogenic life-style in a tree host. We found that the Oc-j genome contains a greater number of genes in these gene families compared to other species in Diaporthales. These gene families include secreted CAZymes, kinases, cytochrome P450, efflux pumps, and secondary metabolism gene clusters. The large numbers of these genes provide Oc-j with an arsenal to cope with the specific ecological niche as a pathogen of the butternut tree.

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