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 Lactobacillus or Streptococcus and useful as promoters. The invention further relates to vectors comprising the said nucleic acids and host cells transformed therewith. The invention also covers the use of host cells comprising the said nucleic acids or vectors for expressing heterologous or homologous proteins and also for delivery, especially therapeutic delivery, of the said proteins to subjects.
