Proceedings of the 10th International Colloquium on Paratuberculosis

#45
Identification <strong>of</strong> genes expressed by Mycobacterium avium subsp. paratuberculosis in subclinical
Johne’s disease and in vitro infected macrophages
Sajan George, Wayne Xu, Zeng Jin Tu, Jeremy Schefers, Srinand Sreevatsan
Veterinary Population Medicine, University <strong>of</strong> Minnesota, USA; Minnesota Supercomputing Institute, University <strong>of</strong>
Minnesota, USA; Veterinary Diagnostic Laboratory, University <strong>of</strong> Minnesota, USA
Mycobacterium avium subsp. paratuberculosis (MAP) uses a diverse set <strong>of</strong> genes in <strong>the</strong> cellular environment
for its survival and pathogenesis. We hypo<strong>the</strong>sized that genes expressed exclusively in <strong>the</strong> in tissues or in
macrophages would contribute to MAP virulence. We studied <strong>the</strong> MAP gene regulation in ileum and mesenteric
lymph nodes <strong>of</strong> two subclinical Johne’s disease (JD) animals or in an in vitro macrophage infection model. Total
RNA was extracted from tissues or in vitro infected monocyte derived macrophages. Mycobacterial mRNA
was enriched and amplified, reverse transcribed to cDNA and competitively hybridized to a MAP K10 microarrays.
We evaluated only those genes differentially expressed in tissues distinct from those expressed in a nutrient
rich broth environment. Genes related to cell envelope biogenesis, carbohydrate metabolism (glucose-6phosphates,
glucokinases), fatty acid metabolism (acyl-coA dehydrogenases, glycosyl transferases), virulence
(MCE family proteins, PPE family proteins, serine/threonine protein kinases), transcriptional regulators, ABC
transporters and oxidoreductases were differentially expressed by MAP in tissues or macrophages. Gene expression
patterns were similar between <strong>the</strong> infected tissues and macrophage infection at three time points and
shared common functions as determined by pathway analysis. Our analysis establishes a repertoire <strong>of</strong> genes
used by MAP in <strong>the</strong> host, which is expected to aid in <strong>the</strong> development <strong>of</strong> successful vaccination strategies for
<strong>the</strong> effective control <strong>of</strong> JD in herd level.
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