A U.S. Patent for “Methods and Compositions for Expression of Polypeptides in a Cell” was awarded to Celltheon on January 21st, 2020. The present invention are new methods for expression of polypeptides in cells that utilize new nucleic acid vectors, also disclosed herein. The vectors include transcriptional regulatory sequences derived from viral genomes, such as the cytomegalovirus (CMV) genome. In some embodiments, the expression vectors further include a post-transcriptional regulatory element (PRE). In some embodiments, the expression vectors further include a MAR/SAR sequence. These vectors provide higher expression levels of genes to which they are operatively linked… Learn More