An isolated nucleic acid encoding a leader, which has a specific sequence, an isolated leader peptide encoded by such nucleic acid, an expression cassette comprising such nucleic acid encoding a leader operably linked to a nucleic acid sequence encoding a POI a recombinant yeast host cell or a vector comprising such expression cassette, a method of producing a POI in such yeast host cell, and further the use of the specific nucleic acid for the secretion of a POT from a host cell and/or to increase the secretion of a POT from a host cell.