1. Department of Animal Science, Biotechnical Faculty; University of Ljubljana; Groblje 3 Domzale 1230 Slovenia
2. Institute of Biochemistry, Faculty of Medicine, University of Ljubljana; Vrazov Trg 2 Ljubljana 1000 Slovenia
3. National Institute of Chemistry; Hajdrihova 19 Ljubljana 1001 Slovenia
4. Department of Experimental Therapeutics and The Center for RNA Interference and Non-Coding RNAs; The University of Texas, M.D. Anderson Cancer Center; So Campus Research Bldg 3, 1881 East Road Houston Texas 77030 USA