title: Evolution and function of tandem repeats in the major surface protein 1a of the ehrlichial pathogen Anaplasma marginale.
abstract: The major surface protein (MSP) 1a of the ehrlichial cattle pathogen Anaplasma marginale, encoded by the single-copy gene msp1alpha, has been shown to have a neutralization-sensitive epitope and to be an adhesin for bovine erythrocytes and tick cells. msp1alpha has been found to be a stable genetic marker for the identification of geographic isolates of A. marginale throughout development in acutely and persistently infected cattle and in ticks. The molecular weight of MSP1a varies among geographic isolates of A. marginale because of a varying number of tandemly repeated peptides of 28-29 amino acids. Variation in the sequence of the tandem repeats occurs within and among isolates, and may have resulted from evolutionary pressures exerted by ligand-receptor and host-parasite interactions. These repeated sequences include markers for tick transmissibility that may be important in the identification of ehrlichial pathogens because they may influence control strategies and the design of subunit vaccines.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA. jose_delafuente@yahoo.com
authors.forename: J
authors.initials: J
authors.lastname: de La Fuente
authors.forename: J C
authors.initials: JC
authors.lastname: Garcia-Garcia
authors.forename: E F
authors.initials: EF
authors.lastname: Blouin
authors.forename: S D
authors.initials: SD
authors.lastname: Rodríguez
authors.forename: M A
authors.initials: MA
authors.lastname: García
authors.forename: K M
authors.initials: KM
authors.lastname: Kocan
mesh_terms: D000595:Amino Acid Sequence; D000709:Anaplasma / Q000145:classification / Q000235:genetics*; D000712:Anaplasmosis / Q000382:microbiology* / Q000635:transmission; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D005819:Genetic Markers; D005843:Geography; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics; D016415:Sequence Alignment / Q000662:veterinary; D020080:Tandem Repeat Sequences / Q000235:genetics*; D017282:Tick-Borne Diseases / Q000382:microbiology; D014481:United States
chemical_list: D001425:Bacterial Outer Membrane Proteins; D005819:Genetic Markers; C449089:major surface protein 1a, Anaplasma