The present invention relates to a DNA molecule or vector and a host cell containing the DNA molecule or vector which can be used to produce a heterologous polypeptide under conditions that elicit a cold shock response in the host cell. The DNA molecule and vector include a nucleotide sequence encoding a heterologous polypeptide and a promoter and 5'-UTR from a cold shock inducible gene which directs its expression. IN addition, an AT-rich sequence that enhances translation under cold shock inducible conditions is either present in the coding sequence of the heterologous polypeptide or in an additional element inserted between the coding sequence and the cold shock inducible promoter and 5'-UTR.