title: Cloning and characterization of putative zinc protease genes of Ehrlichia canis.
abstract: A putative zinc protease gene operon from Ehrlichia canis was cloned and sequenced. A genomic library was constructed in a pHG165 plasmid vector using Sau3A partially digested E. canis chromosomal DNA. Sequence analysis of the insert DNA from this clone indicated two open reading frames with a size of 1314 and 1350 bp that encodes for ProA and ProB, respectively. Based on BLAST analyses, ProA and ProB share 20-30% identities with members of the eukaryotic mitochondrial processing peptidase (MPP) subfamily, which are heterodimers containing alpha and beta subunits. The subunits share a 20% of identity, but only MPP-beta contains a conserved zincbinding motif, His-Xaa-Xaa-Glu-His (HXXEH). proA and proB are also detectable in E. canis and Ehrlichia chaffeensis, but not the Anaplasma phagocytophila. 5'-RACE revealed that the 5' end of the proA mRNA is heterogeneous, containing additional adenine residues that may be directed by pseudo-templated transcription. Although ProA was identified in both E. canis and E. chaffeensis, ProB was detected only in E. canis. ProA and ProB were both detectable in E. canis-infected DH82 cells. Sera from dogs, which were either naturally or experimentally infected with E. canis, recognized both the recombinant protein antigens.
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Ching-Hao
authors.initials: CH
authors.lastname: Teng
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Barr
authors.forename: Yung-Fu
authors.initials: YF
authors.lastname: Chang
mesh_terms: D001426:Bacterial Proteins; D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D019992:Databases as Topic; D019281:Dimerization; D041061:Ehrlichia canis / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D015723:Gene Library; D005816:Genetic Complementation Test; D008666:Metalloendopeptidases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014158:Transcription, Genetic; D015032:Zinc / Q000737:chemistry / Q000378:metabolism*; D000096122:Mitochondrial Processing Peptidase
chemical_list: D001426:Bacterial Proteins; D004247:DNA; D018076:DNA, Complementary; D008666:Metalloendopeptidases; D012333:RNA, Messenger; D011994:Recombinant Proteins; D015032:Zinc; D000096122:Mitochondrial Processing Peptidase; C480082:ProA protein, Ehrlichia canis; C480083:ProB protein, Ehrlichia canis