A plant orthologue of RNase L inhibitor (RLI) is induced in plants showing RNA interference

RNase L inhibitors (RLIs) correspond to a group of soluble proteins from the large ATP binding cassette (ABC) family of proteins. Structurally, RLIs have an N-terminal Fe-S domain and two nucleotide binding domains. Orthologous RLI sequences with more than 48% identity have been found from Archea to Eukaryota, but have not as yet been identified in Eubacteria. Some organisms, like Arabidopsis thaliana and human, have paralogous genes with differential expression patterns, the function of which remains to be determined. Expression of Arabidopsis RLI2 was slightly increased in transgenic plants showing RNA interference, suggesting a role in this pathway.