An eleven-base-pair sequence determines the specificity of DNA uptake in Haemophilus transformation

Danner, David B.; Deich, R A; Sisco, Kenneth L.; Smith, Hamilton O.

doi:10.1016/0378-1119(80)90071-2

Cited by 179 publications

(105 citation statements)

References 11 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…Hi is naturally transformable, taking up DNA from its environment by the recognition of specific Hi uptake sequences in free DNA (Danner et al, 1980) and integrating it into its chromosome (Goodgal & Herriott, 1961;Smith et al, 1981). The precise mechanism of competence in Hi remains incompletely understood, although many proteins important for competence have been identified, including those that make up structures implicated in uptake on the surface of the cells (ComE, PilA), those that are in the periplasm/inner membrane (ComF, ComC, Rec-2) and the cytoplasm (ComA, DprA, ComM) (Gwinn et al, 1998;Karudapuram et al, 1995;Karudapuram & Barcak, 1997;Larson & Goodgal, 1991;McCarthy, 1989;Tomb et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Population subdivision and the detection of recombination in non-typable Haemophilus influenzae

2012

View full text Add to dashboard Cite

The disparity in diversity between unencapsulated (non-typable; NT) and encapsulated, serotypable Haemophilus influenzae (Hi) has been recognized for some time. It has previously been suggested that the wider diversity evidenced within NTHi compared with typable lineages may be due to different rates of recombination within the encapsulated and NT populations. To examine whether there is evidence for different levels of recombination within typable and NT lineages of Hi, we performed a statistical genetic analysis of 819 distinct genotypes of Hi to explore the congruence of serotype with population genetic clustering, and to identify patterns of recombination within the Hi population. We find that a significantly larger proportion of NT isolates show evidence of recombination, compared with typable isolates, and also that when admixture is present, the total amount of recombination per strain is greater within NT isolates, compared with the typable population. Furthermore, we demonstrate significant heterogeneity in the number of admixed individuals between NT lineages themselves, while such variation was not observed in typable lineages. This variability suggests that factors other than the presence of capsule are important determinants of recombination rate in the Hi population. INTRODUCTIONHaemophilus influenzae (Hi) is a Gram-negative bacterium commonly isolated from episodes of asymptomatic nasopharyngeal carriage. While the vast majority of Hi exists in carriage rather than disease states, it remains a globally significant pathogen, capable of causing both localized mucosal infections, such as otitis media, and invasive infections, such as meningitis and septicaemia (Turk, 1984). Hi is thought to cause at least three million cases of serious illness every year, mostly in young children (WHO, 2005). To date, six distinct serotypes (designated a-f) of Hi are distinguishable (Pittman, 1930), while a substantial proportion of the population is unencapsulated and so remains non-typable (NT). Of the encapsulated population, serotype b has historically been the most significant pathogen, and is responsible for approximately 95 % of all invasive Hi disease in unvaccinated children (Falla et al., 1993;Peltola, 2000). An effective vaccine against H. influenzae serotype b (Hib) disease has been available since the early 1980s (Anderson, 1983;Chu et al., 1983), and its introduction into childhood immunization programs in the developed world has all but eliminated Hib disease in western countries (for example, see Bisgard et al., 1998;Booy et al., 1997). However, vaccination is rare in many developing countries, where Hib remains a significant cause of mortality, causing an estimated 380 000 deaths each year (WHO, 2005).While Hib disease is controlled by vaccination in the developed world, Hi possessing the other serotypes, as well as NTHi, are also reported to be capable of causing invasive disease (St Geme, 1993;Tsang et al., 2007; WaggonerFountain et al., 1995). NTHi is also a leading cause of economically signific...

show abstract

Section: Introductionmentioning

confidence: 99%

Population subdivision and the detection of recombination in non-typable Haemophilus influenzae

2012

View full text Add to dashboard Cite

show abstract

“…6), and Danner et al (14) have shown that DNA uptake is specifically blocked by ethylation of bases in the USS. Second, the genomes of these species are highly enriched for their preferred sequence, so most fragments larger than 2 kb will contain one or more USSs (18)(19)(20).…”

mentioning

confidence: 98%

“…Although most competent bacteria will take up any DNA, the well characterized competent species of the Neisseriaceae and Pasteurellaceae families preferentially take up DNA from close relatives (12)(13)(14)(15)(16)(17). Two factors are responsible for this bias.…”

mentioning

confidence: 99%

“…Thus under this model accumulation of USSs in the genome might be expected to require (at least) strong kin selection, if not the extreme altruism of programmed cell death (23). However the problem can be greatly simplified by recognizing that, provided the uptake machinery is biased, USSs may be maintained (14,19) or even increase (24) without being beneficial. Instead USSs will accumulate as a direct consequence of the uptake bias, in a form of what is often called ''molecular drive'' (25).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Evolutionary stability of DNA uptake signal sequences in the Pasteurellaceae

Bakkali

Chen

Lee

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The DNA-uptake signal sequence (USS) of the bacterium Haemophilus influenzae is highly over-represented in its genome (1,471 copies of the core sequence AAGTGCGGT), and DNA fragments containing USS are preferentially taken up by competent cells. Because this bias favors uptake of conspecific DNA, USSs are often considered a kind of mate recognition system in bacteria, acting as species-specific barriers against uptake of unrelated DNA. However, the H. influenzae USS is highly over-represented in the genomes of three otherwise-divergent Pasteurellaceae species (Pasteurella multocida, Haemophilus somnus, and Actinobacillus actinomycetemcomitans, 927, 1,205, and 1,760 copies, respectively), suggesting that USSs do not always limit exchange. USSs in all these genomes are mainly in coding regions and show no orientation bias around the chromosome, weakening proposed USS functions in transcription termination and chromosome replication. Alignment of homologous genes was used to determine evolutionary relationships between individual USSs. Most H. influenzae USSs were found to have perfect or imperfect homologs (USS at the same location) in at least one other species, and most USSs in the other species had perfect or imperfect homologs in H. influenzae. These homologies suggest that the use of a common USS is due to inheritance of the USS-based uptake system from a common ancestor of the Pasteurellaceae, and it indicates that individual USSs can be evolutionarily stable elements of their genomes. The pattern is consistent with a molecular drive model of USS evolution, with new USSs arising by mutation and preferentially spread to new genomes by the biased DNA-uptake system. natural competence ͉ transformation ͉ Actinobacillus ͉ Haemophilus ͉ Pasteurella

show abstract

“…(iii) Various biochemical approaches have only identified DNA binding proteins that are involved at late stages during transformation (15,16). Nevertheless, the fact that Neisseria species and Pasteurellaceae favor uptake of homotypic DNA by selectively recognizing genus-specific DNA uptake sequence (DUS) motifs [or uptake signal sequence (USS) as they are known in Pasteurellaceae] is clear evidence of the existence of specific surfaceexposed DNA receptors (5,17,18). None of the known DNA binding proteins involved in transformation show preference for DNA containing DUS/USS, and the nature of the DUS/USS receptors has, thus, remained mysterious.…”

mentioning

confidence: 99%

Specific DNA recognition mediated by a type IV pilin

Cehovin

Simpson

McDowell

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

150

170

View full text Add to dashboard Cite

Natural transformation is a dominant force in bacterial evolution by promoting horizontal gene transfer. This process may have devastating consequences, such as the spread of antibiotic resistance or the emergence of highly virulent clones. However, uptake and recombination of foreign DNA are most often deleterious to competent species. Therefore, model naturally transformable Gramnegative bacteria, including the human pathogen Neisseria meningitidis, have evolved means to preferentially take up homotypic DNA containing short and genus-specific sequence motifs. Despite decades of intense investigations, the DNA uptake sequence receptor in Neisseria species has remained elusive. We show here, using a multidisciplinary approach combining biochemistry, molecular genetics, and structural biology, that meningococcal type IV pili bind DNA through the minor pilin ComP via an electropositive stripe that is predicted to be exposed on the filaments surface and that ComP displays an exquisite binding preference for DNA uptake sequence. Our findings illuminate the earliest step in natural transformation, reveal an unconventional mechanism for DNA binding, and suggest that selective DNA uptake is more widespread than previously thought.DNA receptor | genetic competence

show abstract

An eleven-base-pair sequence determines the specificity of DNA uptake in Haemophilus transformation

Cited by 179 publications

References 11 publications

Population subdivision and the detection of recombination in non-typable Haemophilus influenzae

Population subdivision and the detection of recombination in non-typable Haemophilus influenzae

Evolutionary stability of DNA uptake signal sequences in the Pasteurellaceae

Specific DNA recognition mediated by a type IV pilin

Contact Info

Product

Resources

About