Mutational analysis of the oligomerization domain of the HERV‐K Rec protein

Abstract

Retroviruses insert their genetic material into the host’s genome. When a retrovirus infects a germ cell, its sequence is passed down to subsequent generations‐‐it becomes endogenized. These human endogenous retroviruses (HERVs) remain mostly dormant and are activated in the presence of external signals (e.g. irradiation) or internal signals. Expression of HERV‐K, the most active human endogenous retrovirus, has been associated with cancer and neurological disorders, such as ALS. They also appear to regulate the innate immune system. For one subset of HERV‐K, nuclear export of the RNA genome relies on the successful interaction between a sequence on the viral genome, RcRE, and a viral protein, Rec. The Rec protein is produced from fully‐spliced mRNA and then imported back into the nucleus to bind and oligomerize on the RcRE region of the unspliced viral mRNA. Rec oligomerization is an essential feature of its function and, thus, a potential target for therapeutic intervention. To understand the mechanism of Rec‐RcRE complex formation, Rec variants were constructed via PCR mutagenesis. Residues of segments previously shown to be involved in multimerization were individually substituted by alanine. Functional assays using a RcRE reporter plasmid will be performed on HEK‐293 cells to assess the involvement of each Rec residue in oligomerization.