Domesticated LTR-Retrotransposon -Related Gene () as a Member of the Stress Response Network in .

The most important sources of new components of genomes are transposable elements, which can occupy more than half of the nucleotide sequence of the genome in higher eukaryotes. Among the mobile components of a genome, a special place is occupied by retroelements, which are similar to retroviruses in terms of their mechanisms of integration into a host genome. The process of positive selection of certain sequences of transposable elements and retroviruses in a host genome is commonly called molecular domestication. There are many examples of evolutionary adaptations of (retroviral capsid) sequences as new regulatory sequences of different genes in mammals, where domesticated genes take part in placenta functioning and embryogenesis, regulation of apoptosis, hematopoiesis, and metabolism. The only -related gene has been found in the genome-. According to the large-scale transcriptomic and proteomic analysis data, the gene in is a component of the protein complex involved in the stress response. In this work, we consider the evolutionary processes that led to the formation of a new function of the domesticated gene and its adaptation to participation in the stress response. We discuss the possible functional role of the Gagr as part of the complex with its partners in , and the pathway of evolution of proteins of the complex in eukaryotes to determine the benefit of the domesticated retroelement gene.