RNA recombination is one of the major driving forces in RNA virus evolution. Two mechanisms of this process are known to date. A recombinant RNA molecule may be formed due to the replicative template switching. Recently, there are increasing data about another, nonreplicative mechanism of viral RNA recombination. However, roles of host factors in this process remain poorly understood.We investigated the role of unconventional splicing enzymes in the process of viral RNA recombination, particularly IRE1 endonuclease. IRE1 was shown to be involved in Xbp1 mRNA intron excision in cytoplasm during UPR (unfolded protein response). A chimeric virus with a structure mimicking Xbp1 intron was inserted in a 3D-polymerase coding sequence. These mutations lead to failed viral reproduction due to the open reading frame shift. But reactivation of IRE1 endonuclease activity by chemical inducers of UPR lead to intron excision and restoring viral reproduction. A similar sequence with point mutations disrupting the IRE1 excision site was inserted into the 2A-protease coding sequence of poliovirus. Constructed virus also showed increased viability upon IRE1 activation by chemical inducers of UPR. Taken together our data shows colocalization of poliovirus RNA with IRE1 and a possible role for unconventional splicing enzymes in viral RNA recombination.