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Title: GENOME SCALE COMPARISON OF MYCOBACTERIUM AVIUM SUBSP. PARATUBERCULOSIS WITH MYCOBACTERIUM AVIUM SUBSP. AVIUM REVEALS POTENTIAL DIAGNOSTIC SEQUENCES

Author
item Bannantine, John
item BAECHLER, E - UNIV OF MINNESOTA
item ZHANG, Q - UNIV OF MINNESOTA
item LI, L - UNIV OF MINNESOTA
item KAPUR, V - UNIV OF MINNESOTA

Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 5/23/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The genetic similarity between Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) and other mycobacterial species has confounded the development of M. paratuberculosis-specific diagnostic reagents. Random shotgun sequencing of the M. paratuberculosis genome in our laboratories has shown greater than 98% sequence identity with M. avium subsp. avium (M. avium) in some regions. However, an in silico comparison of the largest annotated M. paratuberculosis contigs, totaling 2,658,271 bp with the unfinished M. avium genome has revealed 27 predicted M. paratuberculosis coding sequences that do not align with M. avium sequences. BLASTP analysis of the 27 predicted coding sequences (genes) shows 24 do not match sequences in public sequence databases such as Genbank. These novel sequences were examined by PCR amplification with genomic DNA from eight mycobacterial species and eight independent isolates of M. paratuberculosis. From these analyses, 21 genes were found to be present in all M. paratuberculosis isolates and absent from all other mycobacterial species tested. One region of the M. paratuberculosis genome contains a cluster of eight genes, arranged in tandem, that is absent in other mycobacterial species. This region spans 4.4 kb and is separated from other predicted coding regions by 1,408 bp upstream and 1,092 bp downstream. The gene upstream of this eight-gene cluster has strong similarity to mycobacteriophage integrase sequences. The GC content of this 4.4-kb region is 66%, which is similar to the rest of the genome, indicating this region was not horizontally acquired recently. Southern hybridization analysis confirms that this gene cluster is present only in M. paratuberculosis. Collectively, these studies suggest that a genomics approach will help in identifying novel M. paratuberculosis genes as candidate diagnostic sequences.