The present invention provides novel artificial nucleic acid molecules encoding at least one antigenic peptide or protein and at least one additional sequence preferably targeting the antigenic peptides or proteins to cellular compartments of interest. Further, the invention provides (pharmaceutical) compositions or vaccines and kits comprising said nucleic acid molecules. The nucleic acid molecules, (pharmaceutical) compositions or vaccines and kits are useful for treating a variety of diseases such as cancer, infectious diseases, autoimmune diseases, allergies or graft-versus host disease.