Modular rewiring in the reductive evolution of protein-protein interaction networks in Giardia

ZAMPONI N; MARINO BUSLJE C; SVARD S; TOUZ MC

Conferencia; 6th International Giardia and Cryptosporidium Conference.; 2017

It has been hypothesized that the absence of complexity in the Giardia genus is a consequence of two fundamental conditions: early separation of the eukaryotic trunk and adaptation to parasitism through a process of reductive evolution. However, the evolutionary mechanisms behind the cellular characteristics of these organisms are unknown.Objective: To describe the intra- and interspecific changes in the patterns of connections of protein-protein interaction networks within the genus Giardia (GlRIPPs)Methods: Protein-protein interaction networks (RIPPs) of 3 strains of Giardia lamblia and Giardia muris were reconstructed. For this purpose, the method called Interology was implemented, which makes use of ortho- logical relations between proteins of different organisms to predict interactions. Results: We obtained 4 RIPPs that presented a topology free of scale and modular structure. From these networks it was possible to predict proteins of importance for these organisms, using topological criteria such as the number of interactions and the clustering coefficient. Conclusions: Careful analysis of the modular structure revealed that the loss of genes in these organisms produces a reorganization of the structure. This was supported by the integration of gene expression data into the networks, which revealed specific patterns of gene activity in different strains and species. Finally, it was possible to determine that gene loss throughout evolution alters the structural roles of proteins in RIPPs, strongly suggesting that genomic reduction in this group of organisms is the result of an adaptation process.