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Expression of Anaplasma marginale major surface protein 2 operon-associated proteins during mammalian and arthropod

Christiane V Löhr1, Kelly A Brayton, Varda Shkap

  • 1Program in Vector-Borne Diseases, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040, USA.

Infection and Immunity
|October 16, 2002
PubMed

Insights

Anaplasma marginale outer membrane proteins OpAG2 and OpAG3 are expressed in mammals and ticks, but OpAG1 is not. This differential expression from a conserved operon highlights pathogen adaptation strategies.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Parasitology

Background:

  • The Anaplasma marginale major surface protein 2 (MSP2) is antigenically variant.
  • MSP2 is expressed from a conserved 3.5-kb operon containing four open reading frames (ORFs): opag3, opag2, opag1, and msp2.

Purpose of the Study:

  • To investigate the expression patterns of operon genes in Anaplasma marginale during different life cycle stages.
  • To understand the differential expression of outer membrane proteins within the MSP2 operon.

Main Methods:

  • Analysis of operon structure conservation across distinct Anaplasma strains (A. marginale, A. ovis, A. centrale).
  • Detection of OpAG protein expression in mammalian hosts, Ixodes scapularis tick cell lines, and Dermacentor spp. during feeding using molecular techniques.

Main Results:

  • The MSP2 operon structure is conserved across Anaplasma species.
  • OpAG2 and OpAG3 are expressed in the mammalian host and tick cell lines, localizing to the bacterial surface.
  • Differential expression observed in ticks: only OpAG2 expressed during Dermacentor spp. feeding, with no OpAG1 detected in any stage.

Conclusions:

  • Differential outer membrane protein expression from a single operon is a novel finding in tick-borne bacteria.
  • The regulation of this operon may be crucial for Anaplasma adaptation between mammalian hosts and tick vectors.

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