InterPro domain: IPR005380

This XS (named after rice gene X and SGS3) domain is a single-stranded RNA-binding domain (RBD) and possesses a unique version of a RNA recognition motif (RRM) fold [ 1 ]. It is conserved in a family of plant proteins including gene X and SGS3. Although its function is still unknown, the plant SGS3 proteins are thought to be involved in post-transcriptional gene silencing (PTGS) pathways [ 2 ]. In addition, they contain a conserved aspartate residue that may be functionally important.

1. The XS domain of a plant specific SGS3 protein adopts a unique RNA recognition motif (RRM) fold. Cell Cycle 7, 2268-70
2. INVOLVED IN DE NOVO 2-containing complex involved in RNA-directed DNA methylation in Arabidopsis. Proc. Natl. Acad. Sci. U.S.A. 109, 8374-81