The MAPAC combined Mycobacterium avium subspecies paratuberculosis and Mycobacterium avium subspecies avium genome microarray reveals variable duplications of large genomic regions (VSP`s) with low GC% flanked by transportable elements
Comunicación oral en 29th Annual Congress of European Society of Mycobacteriology
6 de julio de 2008
Bull T., Castellanos E., Linedale L., Gould K., de Juan L., Aranaz A. y Hinds J.
Purpose of the study: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.
 | Servicio de Micobacterias (MYC). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM). |
| Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM). |
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