Point mutation or overexpression of A. fumigatus cyp51B, encoding lanosterol 14α-sterol demethylase, leads to triazole resistance.

2021 ◽  
Author(s):  
Mariana Handelman ◽  
Zohar Meir ◽  
Jennifer Scott ◽  
Yona Shadkchan ◽  
Wei Liu ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Point Mutation ◽  
Clinical Isolate ◽  
Recipient Strain ◽  
Antifungal Treatment ◽  
Ergosterol Biosynthesis ◽  
Common Cause ◽  
Clinical Resistance

Aspergillus fumigatus is the most common cause of invasive fungal mold infections in immunocompromised individuals. Current antifungal treatment relies heavily on the triazole antifungals which inhibit fungal Erg11/Cyp51 activity and subsequent ergosterol biosynthesis. However, resistance, due primarily to cyp51 mutation, is rapidly increasing. A. fumigatus contains two Cyp51 isoenzymes, Cyp51A and Cyp51B. Overexpression and mutation of Cyp51A is a major cause of triazole resistance in A. fumigatus . The role of Cyp51B in generating resistance is unclear. Here we show that overexpression or mutation of cyp51B results in triazole resistance. We demonstrate that introduction of a G457S Cyp51B mutation identified in a resistant clinical isolate, results in voriconazole resistance in the naïve recipient strain. Our results indicate that mutations in cyp51B resulting in clinical resistance do exist and should be monitored.

scholarly journals A Novel SRY Pathogenic Variant from a 46,XY Female Harboring a Nonsense Point Mutation (G to A) in Position 293

2021 ◽  
Author(s):  
Shengfang Qin ◽  
Xueyan Wang ◽  
Yunxing Li
Keyword(s):  
Point Mutation ◽  
Gene Mutation ◽  
Molecular Diagnosis ◽  
Novel Mutation ◽  
Pathogenic Variant ◽  
Sry Gene ◽  
Pathogenic Role ◽  
Common Cause ◽  
Xy Female

SRY gene mutation is a common cause of 46,XY female. We report a 46,XY female with a novel mutation of SRY c.293G>A (p.Trp98ter). Our report provides evidence for a pathogenic role of the SRY gene c.293G>A mutation in an individual and enlarges the spectrum of molecular diagnosis for these patients.

Insights in the molecular mechanisms of an azole stress adapted laboratory-generated Aspergillus fumigatus strain

2021 ◽  
Author(s):  
Marion Aruanno ◽  
Samantha Gozel ◽  
Isabelle Mouyna ◽  
Josie E Parker ◽  
Daniel Bachmann ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Aspergillus Fumigatus ◽  
Molecular Mechanisms ◽  
Drug Transporters ◽  
Major Facilitator Superfamily ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Drug Transporter

Abstract Aspergillus fumigatus is the main cause of invasive aspergillosis, for which azole drugs are the first-line therapy. Emergence of pan-azole resistance among A. fumigatus is concerning and has been mainly attributed to mutations in the target gene (cyp51A). However, azole resistance may also result from other mutations (hmg1, hapE) or other adaptive mechanisms. We performed microevolution experiment exposing an A. fumigatus azole-susceptible strain (Ku80) to sub-minimal inhibitory concentration of voriconazole to analyze emergence of azole resistance. We obtained a strain with pan-azole resistance (Ku80R), which was partially reversible after drug relief, and without mutations in cyp51A, hmg1, and hapE. Transcriptomic analyses revealed overexpression of the transcription factor asg1, several ATP-binding cassette (ABC) and major facilitator superfamily transporters and genes of the ergosterol biosynthesis pathway in Ku80R. Sterol analysis showed a significant decrease of the ergosterol mass under voriconazole exposure in Ku80, but not in Ku80R. However, the proportion of the sterol compounds was similar between both strains. To further assess the role of transporters, we used the ABC transporter inhibitor milbemycine oxime (MLB). MLB inhibited transporter activity in both Ku80 and Ku80R and demonstrated some potentiating effect on azole activity. Criteria for synergism were reached for MLB and posaconazole against Ku80. Finally, deletion of asg1 revealed some role of this transcription factor in controlling drug transporter expression, but had no impact on azole susceptibility. This work provides further insight in mechanisms of azole stress adaptation and suggests that drug transporters inhibition may represent a novel therapeutic target. Lay Summary A pan-azole-resistant strain was generated in vitro, in which drug transporter overexpression was a major trait. Analyses suggested a role of the transporter inhibitor milbemycin oxime in inhibiting drug transporters and potentiating azole activity.

scholarly journals Are Point Mutations in HMG-CoA Reductases (Hmg1 and Hmg2) a Step towards Azole Resistance in Aspergillus fumigatus?

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5975
Author(s):  
Irene Gonzalez-Jimenez ◽  
Jose Lucio ◽  
Alejandra Roldan ◽  
Laura Alcazar-Fuoli ◽  
Emilia Mellado
Keyword(s):  
Aspergillus Fumigatus ◽  
Structural Changes ◽  
Survival Rates ◽  
Point Mutations ◽  
Resistance Mechanisms ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Recent Emergence ◽  
Resistant Strains

Invasive aspergillosis, mainly caused by Aspergillus fumigatus, can lead to severe clinical outcomes in immunocompromised individuals. Antifungal treatment, based on the use of azoles, is crucial to increase survival rates. However, the recent emergence of azole-resistant A. fumigatus isolates is affecting the efficacy of the clinical therapy and lowering the success rate of azole strategies against aspergillosis. Azole resistance mechanisms described to date are mainly associated with mutations in the azole target gene cyp51A that entail structural changes in Cyp51A or overexpression of the gene. However, strains lacking cyp51A modifications but resistant to clinical azoles have recently been detected. Some genes have been proposed as new players in azole resistance. In this study, the gene hmg1, recently related to azole resistance, and its paralogue hmg2 were studied in a collection of fifteen azole-resistant strains without cyp51A modifications. Both genes encode HMG-CoA reductases and are involved in the ergosterol biosynthesis. Several mutations located in the sterol sensing domain (SSD) of Hmg1 (D242Y, G307D/S, P309L, K319Q, Y368H, F390L and I412T) and Hmg2 (I235S, V303A, I312S, I360F and V397C) were detected. The role of these mutations in conferring azole resistance is discussed in this work.

scholarly journals Structural basis for a complex I mutation that blocks pathological ROS production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhan Yin ◽  
Nils Burger ◽  
Duvaraka Kula-Alwar ◽  
Dunja Aksentijević ◽  
Hannah R. Bridges ◽  
...  
Keyword(s):  
Point Mutation ◽  
Complex I ◽  
Structural Changes ◽  
Ischemia Reperfusion ◽  
Single Point ◽  
Structural Basis ◽  
Single Point Mutation ◽  
Ros Production

AbstractMitochondrial complex I is central to the pathological reactive oxygen species (ROS) production that underlies cardiac ischemia–reperfusion (IR) injury. ND6-P25L mice are homoplasmic for a disease-causing mtDNA point mutation encoding the P25L substitution in the ND6 subunit of complex I. The cryo-EM structure of ND6-P25L complex I revealed subtle structural changes that facilitate rapid conversion to the “deactive” state, usually formed only after prolonged inactivity. Despite its tendency to adopt the “deactive” state, the mutant complex is fully active for NADH oxidation, but cannot generate ROS by reverse electron transfer (RET). ND6-P25L mitochondria function normally, except for their lack of RET ROS production, and ND6-P25L mice are protected against cardiac IR injury in vivo. Thus, this single point mutation in complex I, which does not affect oxidative phosphorylation but renders the complex unable to catalyse RET, demonstrates the pathological role of ROS production by RET during IR injury.

Decreased cellular cholesterol efflux is a common cause of familial hypoalphalipoproteinemia: role of the ABCA1 gene mutations

2000 ◽  
Vol 152 (2) ◽  
pp. 457-468 ◽  
Author(s):  
Stephanie Mott ◽  
Lu Yu ◽  
Michel Marcil ◽  
Betsie Boucher ◽  
Colette Rondeau ◽  
...  
Keyword(s):  
Cholesterol Efflux ◽  
Gene Mutations ◽  
Cellular Cholesterol ◽  
Common Cause ◽  
Abca1 Gene ◽  
Cellular Cholesterol Efflux

Role of TREM-1 in response to Aspergillus fumigatus infection in corneal epithelial cells

2014 ◽  
Vol 23 (1) ◽  
pp. 288-293 ◽  
Author(s):  
Li-ting Hu ◽  
Zhao-dong Du ◽  
Gui-qiu Zhao ◽  
Nan Jiang ◽  
Jing Lin ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Aspergillus Fumigatus ◽  
Corneal Epithelial Cells ◽  
Corneal Epithelial

scholarly journals CRISPR/Cas9-mediated mutation revealed cytoplasmic tail is dispensable for IZUMO1 function and male fertility

Reproduction ◽  
2016 ◽  
Vol 152 (6) ◽  
pp. 665-672 ◽  
Author(s):  
Samantha A M Young ◽  
Haruhiko Miyata ◽  
Yuhkoh Satouh ◽  
Masanaga Muto ◽  
Martin R Larsen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Point Mutation ◽  
Male Fertility ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Cytoplasmic Tail ◽  
Binding Partner ◽  
C Terminus ◽  
Manipulation System

IZUMO1 is a protein found in the head of spermatozoa that has been identified as essential for sperm–egg fusion. Its binding partner in the egg has been discovered (JUNO); however, the roles of several domains within IZUMO1 remain unexplored. One such domain is the C-terminus, which undergoes major phosphorylation changes in the cytoplasmic portion of the protein during rat epididymal transit. However, the cytoplasmic tail of IZUMO1 in many species is highly variable, ranging from 55 to one amino acid. Therefore, to understand the role of the cytoplasmic tail of IZUMO1 in mouse, we utilised the gene manipulation system of CRISPR/Cas9 to generate a point mutation resulting in a premature stop codon, producing mice with truncated IZUMO1. Mice without the cytoplasmic tail of IZUMO1 showed normal fertility but decreased the amount of protein, indicating that whilst this region is important for the expression level of IZUMO1, it is dispensable for fertilisation in the mouse.

scholarly journals Role of the cAMP and MAPK pathways in the transformation of mouse 3T3 fibroblasts by a TSHR gene constitutively activated by point mutation

Oncogene ◽  
2000 ◽  
Vol 19 (42) ◽  
pp. 4896-4905 ◽  
Author(s):  
J A Du Villard ◽  
R Wicker ◽  
P Crespo ◽  
D Russo ◽  
S Filetti ◽  
...  
Keyword(s):  
Point Mutation ◽  
Mapk Pathways ◽  
3T3 Fibroblasts ◽  
Tshr Gene
Sign in / Sign up

Export Citation Format

Share Document