title: Conservation of major surface protein 1 genes of Anaplasma marginale during cyclic transmission between ticks and cattle.
abstract: Bovine anaplasmosis is a rickettsial disease of world-wide economic importance caused by Anaplasma marginale. Several major surface proteins with conserved gene sequences have been examined as potential candidates for vaccines and/or diagnostic assays. Major surface protein 1 (MSP1) is composed of polypeptides MSP1a and MSP1b. MSP1a is expressed from the single copy gene msp1 alpha and MSP1b is expressed by members of the msp1 beta multigene family. In order to determine if the msp1 genes are conserved, primers specific for msp1 alpha, msp1 beta(1), and msp1 beta(2) genes were synthesized and used to amplify msp1 sequences of A. marginale from tick cell cultures, from cattle during acute and chronic infections and from salivary glands of Dermacentor variabilis. Protein sequences of MSP1a, MSP1b(1) and MSP1b(2) were conserved during the life cycle of the parasite. No amino acid changes were observed in MSP1a. However, small variations were observed in the MSP1b(1) and MSP1b(2) protein sequences, which could be attributed to recombination, selection for sub-populations of A. marginale in the vertebrate host and/or PCR errors. Several isolate-specific sequences were also observed. Based on the information obtained in this study, the MSP1 protein appears to be fairly well conserved and a potential vaccine candidate.
authors.affiliation: Department of Pathobiology, University of Florida, PO Box 110880, Gainesville, FL 32611-0880, USA. mbowie@ufl.edu
authors.forename: Michael V
authors.initials: MV
authors.lastname: Bowie
authors.forename: Jose
authors.initials: J
authors.lastname: de la Fuente
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Kocan
authors.forename: Edmour F
authors.initials: EF
authors.lastname: Blouin
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Barbet
mesh_terms: D000595:Amino Acid Sequence; D000709:Anaplasma / Q000235:genetics*; D000712:Anaplasmosis / Q000635:transmission; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D013987:Ticks / Q000382:microbiology*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; C449089:major surface protein 1a, Anaplasma; C450434:major surface protein 1b, Anaplasma