The invention relates to an artificial nucleic acid molecule comprising at least one open reading frame and at least one 3′；-untranslated region element (3′；-UTR element) and/or at least one 5′；-untranslated region element (5′；-UTR element), wherein the at least one 3′；-UTR element and/or the at least one 5′；-UTR element prolongs and/or increases protein production from said artificial nucleic acid molecule and wherein the at least one 3′；-UTR element and/or the at least one 5′；-UTR element is derived from a stable mRNA. The invention further relates to the use of such an artificial nucleic acid molecule in gene therapy and/or genetic vaccination. Furthermore, methods for identifying a 3′；-UTR element and/or a 5′；-UTR derived from a stable mRNA element are disclosed.
