Caracterização de genes da oxidase alternativa (AOX) no tardígrado Hypsibius dujardini

Abstract

Tardigrades, also known as water bears, are microscope animals that belong to the Ecdysozoa supergroup and they can be found in almost every ecosystems of the Earth. These organisms feed themselves on microalgae and phytoplankton and can be adapted to extreme environments. Because of these factors, since its discovery, they have been increasingly targeted by studies in order to understand how they survive under these conditions and how they became more resistant when exposed to these conditions, like the space vacuum. These resistance to extreme environments are assigned to lot of factors, among them the Reactive Oxygen Species (ROS) defense system of tardigrades. The Alternative Oxidase (AOX), present in the inner membrane of the mitochondria, was previously found in plants, fungi, protists and some minor animals. Among some functions attributed to the enzyme it decreases the potential for ROS formation and thus is seen as an initiator of cell reprogramming under stressful conditions, making it interesting to study the existence of AOX in tardigrades. Thus, the aim of this work was to identify AOX gene(s) in available genomic data of the species Hypsibius dujardini and to evaluate gene expression in RNA-seq experiments in order to advance the knowledge about a possible role of AOX in tardigrades. Using transcriptomic data available at the NCBI and AOX sequence data from Hypsibius dujardini, this work seeks to elucidate the AOX expression profile during the organism's development and under stress conditions. For this, the sequence of the AOX gene was analyzed and annotated, and the relationship of this gene and the expression profile itself were phylogenetically evaluatedusing bioinformatics tools such as Rstudio. From the analyzes performed, it was possible to identify two genes related to AOX in the tardigrade genome, called AOX gene and pseudogene, and the phylogenetic analysis indicated that the AOX gene is closer to those of other animals. With regard to transcriptomic data, it was possible to infer that the AOX gene is more expressed in the transition phases that occur during the animal's development, as well as in stress conditions that lead to anhydrobiosis.