Zinc efflux in Trichomonas vaginalis: In silico identification and expression analysis of CDF-like genes

Abstract

Zinc (Zn) is a common essential component for all organisms because this metal serves as a cofactor or structural element for enzymes and metalloproteins involved in several important biological processes. However, excess levels of Zn can be toxic, as a consequence, the cells have evolved homeostatic mechanisms to regulate intracellular levels of this trace mineral. Zinc efflux and sequestration into internal cellular compartments from cells are mediated, in large part, by the ZNT/SLC30 proteins, which belong to the CDF family of ion transporters. The CDF family has evolved in prokaryotes and has been reported in several organisms, such as fungi, plants, and animals. Zn has been shown to regulate expression of proteins involved in metabolism and pathogenicity mechanisms in the protozoan pathogen Trichomonas vaginalis, in contrast high concentrations of this element were also found to be toxic for T. vaginalis trophozoites. Until now, Zn homeostasis mechanisms are not yet clear in this parasite.We performed a genome-wide analysis and localized eight members of the CDF gene family in T. vaginalis (TvCDF1-8). With the use of in silico analyses, the TvCDF protein sequences revealed high conservation and show similar properties to the reported in other CDF orthologs. We analyzed the expression patterns of TvCDF1-8 transcripts in trophozoites growth under high zinc concentrations, which showed down-regulation in expression. These results indicate that TvCDF genes encode membrane transporters and strongly supported their identity as members of CDF-like gene family, and further suggest the function in Zn efflux and sequestration in T. vaginalis.