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A biphasic epigenetic switch controls immunoevasion, virulence and niche adaptation in non-typeable Haemophilus influenzae.

Atack JM, Srikhanta YN, Fox KL, Jurcisek JA, Brockman KL, Clark TA, Boitano M, Power PM, Jen FE, McEwan AG, Grimmond SM, Smith AL, Barenkamp SJ, Korlach J, Bakaletz LO, Jennings MP - Nat Commun (2015)

Bottom Line: Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles.Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4).Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system.

View Article: PubMed Central - PubMed

Affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia.

ABSTRACT
Non-typeable Haemophilus influenzae contains an N(6)-adenine DNA-methyltransferase (ModA) that is subject to phase-variable expression (random ON/OFF switching). Five modA alleles, modA2, modA4, modA5, modA9 and modA10, account for over two-thirds of clinical otitis media isolates surveyed. Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles. Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4). Analyses of a modA2 strain in the chinchilla model of otitis media show a clear selection for ON switching of modA2 in the middle ear. Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system.

No MeSH data available.


Related in: MedlinePlus

Analysis of outer-membrane protein (OMP) preparations.(a) Silver-stained gel of each modA ON/OFF pair; (b) western blots using antibodies against currently investigated vaccine candidates. Full western blots are presented in Supplementary Fig. 5; (c) ELISA results for HMW in modA2, modA4 and modA5 ON/OFF strain pairs using primary antibody AD6. Values presented are mean values±s.d. Each experiment was carried out in triplicate. P values were calculated using Student's t-test based on specific titres in the linear range of the response curve (*=<0.01; **=<0.001). Full ELISA data are presented in Supplementary Data 1.
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f3: Analysis of outer-membrane protein (OMP) preparations.(a) Silver-stained gel of each modA ON/OFF pair; (b) western blots using antibodies against currently investigated vaccine candidates. Full western blots are presented in Supplementary Fig. 5; (c) ELISA results for HMW in modA2, modA4 and modA5 ON/OFF strain pairs using primary antibody AD6. Values presented are mean values±s.d. Each experiment was carried out in triplicate. P values were calculated using Student's t-test based on specific titres in the linear range of the response curve (*=<0.01; **=<0.001). Full ELISA data are presented in Supplementary Data 1.

Mentions: To determine whether modA switching altered the expression of outer-membrane proteins (OMPs), outer-membrane samples were separated using Bis-Tris PAGE gels and silver stained (Fig. 3a) to explore whether any gross protein differences existed within each modA ON/OFF strain pair. Clear differences could be visualized within the OMP profile of each modA ON/OFF pair (noted by arrows in Fig. 3a), indicating that modA phase variation influences the OMP profile, and may therefore influence immunoevasion, pathogenesis and virulence.


A biphasic epigenetic switch controls immunoevasion, virulence and niche adaptation in non-typeable Haemophilus influenzae.

Atack JM, Srikhanta YN, Fox KL, Jurcisek JA, Brockman KL, Clark TA, Boitano M, Power PM, Jen FE, McEwan AG, Grimmond SM, Smith AL, Barenkamp SJ, Korlach J, Bakaletz LO, Jennings MP - Nat Commun (2015)

Analysis of outer-membrane protein (OMP) preparations.(a) Silver-stained gel of each modA ON/OFF pair; (b) western blots using antibodies against currently investigated vaccine candidates. Full western blots are presented in Supplementary Fig. 5; (c) ELISA results for HMW in modA2, modA4 and modA5 ON/OFF strain pairs using primary antibody AD6. Values presented are mean values±s.d. Each experiment was carried out in triplicate. P values were calculated using Student's t-test based on specific titres in the linear range of the response curve (*=<0.01; **=<0.001). Full ELISA data are presented in Supplementary Data 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525171&req=5

f3: Analysis of outer-membrane protein (OMP) preparations.(a) Silver-stained gel of each modA ON/OFF pair; (b) western blots using antibodies against currently investigated vaccine candidates. Full western blots are presented in Supplementary Fig. 5; (c) ELISA results for HMW in modA2, modA4 and modA5 ON/OFF strain pairs using primary antibody AD6. Values presented are mean values±s.d. Each experiment was carried out in triplicate. P values were calculated using Student's t-test based on specific titres in the linear range of the response curve (*=<0.01; **=<0.001). Full ELISA data are presented in Supplementary Data 1.
Mentions: To determine whether modA switching altered the expression of outer-membrane proteins (OMPs), outer-membrane samples were separated using Bis-Tris PAGE gels and silver stained (Fig. 3a) to explore whether any gross protein differences existed within each modA ON/OFF strain pair. Clear differences could be visualized within the OMP profile of each modA ON/OFF pair (noted by arrows in Fig. 3a), indicating that modA phase variation influences the OMP profile, and may therefore influence immunoevasion, pathogenesis and virulence.

Bottom Line: Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles.Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4).Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system.

View Article: PubMed Central - PubMed

Affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia.

ABSTRACT
Non-typeable Haemophilus influenzae contains an N(6)-adenine DNA-methyltransferase (ModA) that is subject to phase-variable expression (random ON/OFF switching). Five modA alleles, modA2, modA4, modA5, modA9 and modA10, account for over two-thirds of clinical otitis media isolates surveyed. Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles. Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4). Analyses of a modA2 strain in the chinchilla model of otitis media show a clear selection for ON switching of modA2 in the middle ear. Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system.

No MeSH data available.


Related in: MedlinePlus