Uptake signal sequence (USS) are short DNA sequences preferentially taken up by competent bacteria belonging to the Pasteurellacea family (e.g., Haemophilus influenzae). Similar sequences, called DNA uptake sequence (DUS), are found in species belonging to the Neisseriaceae family (including Neisseria meningitidis and Neisseria gonorrhoeae).
Neisseria meningitides
Genetic transformation is the process by which a recipient bacterial cell takes up DNA from a neighboring cell and integrates this DNA into the recipient’s genome by recombination. In N. meningitidis, DNA transformation requires the presence of short DUS (9-10 mers residing in coding regions) of the donor DNA. Specific recognition of DUSs is mediated by a type IV pilin. Davidsen et al. reported that in N. meningitides DUSs occur at a significantly higher density in genes involved in DNA repair and recombination (as well as in restriction-modification and replication) than in other annotated gene groups. These authors proposed that the over-representation of DUS in DNA repair and recombination genes may reflect the benefit of maintaining the integrity of the DNA repair and recombination machinery by preferentially taking up genome maintenance genes that could replace their damaged counterparts in the recipient cell’s genome. Uptake of such genes could provide a mechanism for facilitating recovery from DNA damage after genotoxic stress.