The present invention describes mRNA usage improving and/or translation-enhancing nucleic acid sequences, nucleic acid constructs comprising such sequences, and host cells comprising such nucleic acid constructs. The invention further pertains to a method for expressing a protein of interest in a cell or organism using such nucleic acid sequences, as well as their uses for increasing intergration of such nucleic acid construct into a genome, for enhancing mRNA usage and/or translation of a recombinantly expressed polypeptide, and for increasing the number of transformants upon transformation of a cell with such nucleic acid construct.