Resumo

Cryptococcus complex has 37 species described, from which C. neoformans and C. gattii stand out for their ability to cause disease in humans and animals. During the infection process, the availability of essential metals is important for host and pathogen. To prevent from pathogenic organisms, host may reduce the availability of these nutrients in a process known as nutritional immunity. It is well described that these essential metals have central roles related to virulence factors expression in pathogenic Cryptococcus species. Micro-RNAs (miRNAs) are important mediators of gene expression in response to metal homeostasis in many biological systems. However, little is known about miRNAs-like expression in C. gattii. Therefore, the aim of this work is to profile the plethora of miRNAs produced by C. gattii during iron and zinc deprivation. C. gattii R265 cells were incubated in three conditions: zinc deprivation (10 µM TPEN chelator), iron deprivation (1 mM BPDS chelator) and control condition. After 18h, RNA extraction was performed with Trizol^® and small RNAs (1-40 nt) sequences were obtained in an Illumina HiSeq 2000 platform. To identify miRNAs in C. gattii, non-redundant reads were aligned to sequences of R265 and WM276 genomes. MIREAP was used for miRNAs prediction and resulted in 63 miRNAs putative genes in R265 and 68 in WM 276, respectively. Precursors obtained with WM 276 lineage had higher count when compared with R265, a possible result from the numerous gaps in R265 genome sequence. In silico analysis of miRNAs differential expression showed that the majority of them are present in the three conditions. However, some are present only in metal deprivation. Thereby, these miRNAs may be exerting some important role at metal homeostasis in response to infection environment mimicry conditions. The identification of the mRNAs targeted by such miRNAs is under investigation. This identification should clarify the role played by miRNAs in the regulation of gene expression in the host-pathogen interaction.