title: Down-regulation of the ALS3 gene as a consequent effect of RNA-mediated silencing of the EFG1 gene in Candida albicans.
abstract: The most important virulence factor which plays a central role in Candida albicans pathogenesis is the ability of this yeast to alternate between unicellular yeast and filamentous hyphal forms. Efg1 protein is thought to be the main positive regulating transcription factor, which is responsible for regulating hyphal-specific gene expression under most conditions. ALS3 is one of the Efg1-associated genes encoding a multi-functional adhesive polypeptide, which mediates adherence to diverse host substrates. In this study, the EFG1 gene was knocked down by using synthetic siRNA in C. albicans and the regulation in ALS3 as one of the Efg1-dependent genes was investigated.
  
  
  
  The 19-nucleotide siRNA was designed based on cDNA sequence of EFG1 gene in C. albicans. Transfection was performed using modified- plyethylen glycol/LiAc method. To quantify the level of EFG1 and the hyphal-specific ALS3 gene expression, the cognate EFG1 and ALS3 mRNA were measured in C. albicans by quantitative real-time RT-PCR.
  
  
  
  Fluorescent microscopy pictures indicated that transfection was performed successfully. Also, according to relative expression software tool, expression of EFG1 gene was decreased significantly with 500 nM siRNA as well as 1 µM siRNA (P<0.05). However, more significant down-regulations were observed in the expression of ALS3 in both concentrations of 500 nM and 1 µM siRNA (P<0.05).
  
  
  
  In conclusion, we demonstrated the down-regulation of ALS3 gene as a consequent of applying EFG1-specific siRNA in C. albicans. This may lead us to design anti-fungal-specific agents in order to face with C. albicans-associated infections.
authors.affiliation: Div. of Molecular Biology, Dept. of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Moazeni
authors.affiliation: Dept. of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Khorramizadeh
authors.affiliation: 3Dept. of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
authors.forename: Ladan
authors.initials: L
authors.lastname: Teimoori-Toolabi
authors.affiliation: Dep. of Biology, Islamic Azad University, Varamin-Pishva Branch, Varamin, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Noorbakhsh
authors.affiliation: Div. of Molecular Biology, Dept. of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Fallahi
authors.affiliation: Div. of Molecular Biology, Dept. of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.|Dept. of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Sassan
authors.initials: S
authors.lastname: Rezaie
mesh_terms: D002176:Candida albicans / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D015536:Down-Regulation; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D034741:RNA, Small Interfering / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection
chemical_list: C113620:ALS3 protein, Candida albicans; D004268:DNA-Binding Proteins; C121438:EFG1 protein, Candida albicans; D005656:Fungal Proteins; D034741:RNA, Small Interfering; D014157:Transcription Factors