This entry represents a domain found in RMND1 from mammals, Sif2/Sif3 from fission yeasts and Rmd1/Rmd8/YDR282C (Mrx10) from budding yeasts. RMND1 and its yeast homologue, Mrx10, are mitochondrial proteins required for mitochondrial translation [, ]. Rmd1 and Rmd8 are cytoplasmic proteins required for sporulation [].