29th Annual Congress of European Society of Mycobacteriology
VISAVET function: participant| Organizer: | European Society of Mycobacteriology (ESM). |
City: Plovdiv
Country: Bulgary
Date: July 6th-9th, 2008
Abstract bookSummary
Investigate mechanisms for variability in Mycobacterium avium subsp. paratuberculosis
Methods: A 60mer oligonucleotide microarray (MAPAC) covering both genomes of Mycobacterium avium subspecies paratuberculosis (MAP) and Mycobacterium avium subspecies avium strain 104 was used to perform comparative genomic studies on a panel of MAP isolates with variant morphologies isolated from a variety of hosts.
Results: The MAPAC microarray was able to define a set of large sequence
polymorphisms (LSP’s) diagnostic for each of the three major 84 European Society of Mycobacteriology types of MAP and deleted LSP’s associated with attenuation in MAP vaccine strains.
In addition, some strains contained up to 17 genomic regions (VSP’s) giving signals suggestive of a series of large genomic regional duplications. VSP’s were predominantly subsets of LSP’s, with significantly low GC% regions and immediately flanked by insertion sequences or integrases. VSP’s were present in only a proportion of any one culture. Confirmation of MAPAC differential signal increases was made using quantitative PCR of a selection of genes within VSP’s (including several
virulence determinants and the rrn operon). Associations could be made between VSP duplications and colony growth rate / morphology. An increase in expression of transposase associated with VSP’s and active transposition resulting in significant alteration of the MAP proteome was demonstrated after infection into a human macrophage cell line.
Conclusion: The control of transposase activity, possibly associated with host
cell entry, may be a mechanism for variation in genome plasticity and
phenotype switching in MAP
