The invention is in the field of molecular biology, and relates to recombinant engineering and protein expression. More in particular, the invention relates to nucleic acids for recombinant expression of proteins comprising sequences derived from Lactococcus and useful as promoters. The invention further relates to vectors comprising the nucleic acids and host cells transformed therewith. The invention also covers the use of host cells comprising the nucleic acids or vectors for expressing heterologous or homologous proteins; and also for delivery, especially therapeutic delivery, of the said proteins to subjects.