Uptake signal sequence

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Uptake signal sequences (USS) are short DNA sequences preferentially taken up by competent bacteria of the family Pasteurellaceae (e.g., Haemophilus influenzae ). Similar sequences, called DNA uptake sequences (DUS), are found in species of the family Neisseriaceae (including Neisseria meningitidis and Neisseria gonorrhoeae ). [1]

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Neisseria meningitidis

Genetic transformation is the process by which a recipient bacterial cell takes up naked DNA from its environement and integrates this DNA into the recipient's genome by recombination. In N. meningitidis , DNA transformation requires the presence of short DUS (10-12 mers residing in coding and intergenic regions) of the donor DNA. Specific recognition of DUSs is mediated by a type IV pilin. [2] Davidsen et al. [3] reported that in N. meningitidis 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.

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<i>Pasteurella multocida</i> Species of bacterium

Pasteurella multocida is a Gram-negative, nonmotile, penicillin-sensitive coccobacillus of the family Pasteurellaceae. Strains of the species are currently classified into five serogroups based on capsular composition and 16 somatic serovars (1–16). P. multocida is the cause of a range of diseases in mammals and birds, including fowl cholera in poultry, atrophic rhinitis in pigs, and bovine hemorrhagic septicemia in cattle and buffalo. It can also cause a zoonotic infection in humans, which typically is a result of bites or scratches from domestic pets. Many mammals and birds harbor it as part of their normal respiratory microbiota.

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Phasevarion

In bacteria, phasevarions mediate a coordinated change in the expression of multiple genes or proteins. This occurs via phase variation of a single DNA methyltransferase. Phase variation of methyltransferase expression results in differential methylation throughout the bacterial genome, leading to variable expression of multiple genes through epigenetic mechanisms.

References

  1. Frye SA, Nilsen M, Tønjum T, Ambur OH (2013). "Dialects of the DNA uptake sequence in Neisseriaceae". PLOS Genet. 9 (4): 3065–70. doi:10.1371/journal.pgen.1003458. PMC   3630211 . PMID   23637627.
  2. Cehovin A, Simpson PJ, McDowell MA, Brown DR, Noschese R, Pallett M, Brady J, Baldwin GS, Lea SM, Matthews SJ, Pelicic V (2013). "Specific DNA recognition mediated by a type IV pilin". Proc. Natl. Acad. Sci. U.S.A. 110 (8): 3065–70. Bibcode:2013PNAS..110.3065C. doi: 10.1073/pnas.1218832110 . PMC   3581936 . PMID   23386723.
  3. Davidsen T, Rødland EA, Lagesen K, Seeberg E, Rognes T, Tønjum T (2004). "Biased distribution of DNA uptake sequences towards genome maintenance genes". Nucleic Acids Res. 32 (3): 1050–8. doi:10.1093/nar/gkh255. PMC   373393 . PMID   14960717.