Interactions between the transcription factors FfmA and AtrR are required to properly regulate gene expression in the fungus <i>Aspergillus fumigatus</i>

Paul, Sanjoy; Stamnes, Mark A; Moye-Rowley, W Scott

doi:10.1093/g3journal/jkad173

“…Sequencing library preparation was done using a NEBNext Ultra II Directional RNA Library Prep Kit for Illumina (GenoHub Inc., Texas, USA). Bioinformatics, utilizing standard methods, were carried out as previously described ( 31 ). The RNA-seq data are available as GEO Series GSE267651.…”

Section: Methodsmentioning

confidence: 99%

Gene-specific transcriptional activation by the Aspergillus fumigatus AtrR factor requires a conserved C-terminal domain

Ror,

Stamnes,

Moye-Rowley

2024

mSphere

Self Cite

0

View full text Add to dashboard Cite

Treatment of fungal infections associated with the filamentous fungus Aspergillus fumigatus is becoming more problematic as this organism is developing resistance to the main chemotherapeutic drug at an increasing rate. Azole drugs represent the current standard-of-care in the treatment of aspergillosis with this drug class acting by inhibiting a key step in the biosynthesis of the fungal sterol ergosterol. Azole compounds block the activity of the lanosterol α-14 demethylase, encoded by the cyp51A gene. A common route of azole resistance involves an increase in transcription of cyp51A . This transcriptional increase requires the function of a Zn2Cys6 DNA-binding domain-containing transcription activator protein called AtrR. AtrR was identified through its action as a positive regulator of expression of an ATP-binding cassette transporter ( abcC / cdr1B here called abcG1 ). Using both deletion and alanine scanning mutagenesis, we demonstrate that a conserved C-terminal domain in A. fumigatus is required for the expression of abcG1 but dispensable for cyp51A transcription. This domain is also found in several other fungal pathogen AtrR homologs consistent with a conserved gene-selective function of this protein segment being conserved. Using RNA sequencing (RNA-seq), we find that this gene-specific transcriptional defect extends to several other membrane transporter-encoding genes including a second ABC transporter locus. Our data reveal that AtrR uses at least two distinct mechanisms to induce gene expression and that normal susceptibility to azole drugs cannot be provided by maintenance of wild-type expression of the ergosterol biosynthetic pathway when ABC transporter expression is reduced. IMPORTANCE Aspergillus fumigatu s is the primary human filamentous fungal pathogen. The principal chemotherapeutic drug used to control infections associated with A. fumigatus is the azole compound. These drugs are well-tolerated and effective, but resistance is emerging at an alarming rate. Most resistance is associated with mutations that lead to overexpression of the azole target enzyme, lanosterol α-14 demethylase, encoded by the cyp51A gene. A key regulator of cyp51A gene expression is the transcription factor AtrR. Very little is known of the molecular mechanisms underlying the effect of AtrR on gene expression. Here, we use deletion and clustered amino acid substitution mutagenesis to map a region of AtrR that confers gene-specific activation on target genes of this transcription factor. This region is highly conserved across AtrR homologs from other pathogenic species arguing that its importance in transcriptional regulation is maintained across evolution.

show abstract

An investigation into the transcription factors and regulatory mechanisms of Aspergillus

Qin,

Yu,

Tian

2024

Food Safety and Health

0

View full text Add to dashboard Cite

Aflatoxins produced by Aspergillus flavus, a group of filamentous fungi widely distributed in nature as foodborne pathogens, are a major threat to food safety. It is thus clear that Aspergillus is inextricably linked to the food sector. Transcription factors enable the correct expression of genes at specific spatial and temporal levels, and they constitute a considerable proportion of the fungal genome sequence. Their presence is particularly important for growth, secondary metabolism, stress response, and pathogenic process of Aspergillus. This article reviews the functional regulatory mechanisms of important transcription factors in the foodborne pathogen Aspergillus flavus and other Aspergillus species, the current status of research technologies, and the potential value of applying them to diverse fields such as food safety, biotechnology, medical health, and agricultural output in the future.

show abstract

Loss of a conserved C-terminal region of theAspergillus fumigatusAtrR transcriptional regulator leads to a gene-specific defect in target gene expression

Ror,

Stamnes,

Moye-Rowley

2024

Preprint

Self Cite

0

View full text Add to dashboard Cite

Treatment of fungal infections associated with the filamentous fungus Aspergillus fumigatus is becoming more problematic as this organism is developing resistance to the main chemotherapeutic drug at an increasing rate. Azole drugs represent the current standard-of-care in treatment of aspergillosis with this drug class acting by inhibiting a key step in biosynthesis of the fungal sterol ergosterol. Azole compounds block the activity of the lanosterol a-14 demethylase, encoded by the cyp51A gene. A common route of azole resistance involves an increase in transcription of cyp51A. This transcriptional increase requires the function of a Zn2Cys6 DNA-binding domain-containing transcription activator protein called AtrR. AtrR was identified through its action as a positive regulator of expression of an ATP-binding cassette transporter (abcC/cdr1B here called abcG1). Using both deletion and alanine scanning mutagenesis, we demonstrate that a conserved C-terminal domain in A. fumigatus is required for expression of abcG1 but dispensable for cyp51A transcription. This domain is also found in several other fungal pathogen AtrR homologues consistent with a conserved gene-selective function of this protein segment being conserved. Using RNA-seq, we find that this gene-specific transcriptional defect extends to several other membrane transporter-encoding genes including a second ABC transporter locus. Our data reveal that AtrR uses at least two distinct mechanisms to induce gene expression and that normal susceptibility to azole drugs cannot be provided by maintenance of wild-type expression of the ergosterol biosynthetic pathway when ABC transporter expression is reduced.

show abstract

Interactions between the transcription factors FfmA and AtrR are required to properly regulate gene expression in the fungus Aspergillus fumigatus

Cited by 3 publications

References 47 publications

Gene-specific transcriptional activation by the Aspergillus fumigatus AtrR factor requires a conserved C-terminal domain

Gene-specific transcriptional activation by the Aspergillus fumigatus AtrR factor requires a conserved C-terminal domain

An investigation into the transcription factors and regulatory mechanisms of Aspergillus

Loss of a conserved C-terminal region of theAspergillus fumigatusAtrR transcriptional regulator leads to a gene-specific defect in target gene expression

Contact Info

Product

Resources

About