YLR107W REX3 SGDID:S000004097, Chr XII from 364116-365330, Genome Release 64-1-1, Verified ORF, "RNA exonuclease; required for maturation of the RNA component of RNase MRP; functions redundantly with Rnh70p and Rex2p in processing of U5 snRNA and RNase P RNA; member of RNase D family of exonucleases"