The DEAD-box RNA helicase Vad1 regulates multiple virulence-associated genes in Cryptococcus neoformans.
The study of fungal regulatory networks is essential to the understanding of how these pathogens respond to host environmental signals with effective virulence-associated traits. In this study, a virulence-associated DEAD-box RNA helicase-encoding gene (VAD1) was isolated from a mutant defective in the virulence factor laccase. A Deltavad1 mutant exhibited a profound reduction in virulence in a mouse model that was restored after reconstitution with WT VAD1. Loss of VAD1 resulted in upregulation of NOT1, a gene encoding a global repressor of transcription. NOT1 was found to act as an intermediary transcriptional repressor of laccase. Vad1 was located within macromolecular complexes that formed cytoplasmic granular bodies in mature cells and during infection of mouse brain. In addition, VAD1 was shown by in situ hybridization to be expressed in the brain of an AIDS patient coinfected with C. neoformans. To understand the role of VAD1 in virulence, a functional genomics approach was used to identify 3 additional virulence determinants dependent on VAD1: PCK1, TUF1, and MPF3, involved in gluconeogenesis, mitochondrial protein synthesis, and cell wall integrity, respectively. These data show that fungal virulence-associated genes are coordinately regulated and that an analysis of such transcriptomes allows for the identification of important new genes involved in the normal growth and virulence of fungal pathogens.
Panepinto
John
J
Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612, USA. panepijc@uic.edu
Liu
Lide
L
Ramos
Jeanie
J
Zhu
Xudong
X
Valyi-Nagy
Tibor
T
Eksi
Saliha
S
Fu
Jianmin
J
Jaffe
H Ari
HA
Wickes
Brian
B
Williamson
Peter R
PR
D020816:Amino Acid Motifs; D000818:Animals; D001921:Brain / Q000166:cytology / Q000382:microbiology; D003453:Cryptococcosis; D003455:Cryptococcus neoformans / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D023281:Genomics; D006801:Humans; D017403:In Situ Hybridization; D042845:Laccase / Q000235:genetics / Q000378:metabolism; D051379:Mice; D010641:Phenotype; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D042845:Laccase; D020365:RNA Helicases