TY - JOUR
T1 - Interdependence of environmental factors influencing reciprocal patterns of gene expression in virulent Borrelia burgdorferi
AU - Yang, Xiaofeng
AU - Goldberg, Martin S.
AU - Popova, Taissia G.
AU - Schoeler, George B.
AU - Wikel, Stephen K.
AU - Hagman, Kayla E.
AU - Norgard, Michael V.
PY - 2000
Y1 - 2000
N2 - The paradigm for differential antigen expression in Borrelia burgdorferi, the agent of Lyme disease, is the reciprocal expression of its outer surface (lipo)proteins (Osp) A and C; as B. burgdorferi transitions from its arthropod vector into mammalian tissue, ospC is upregulated, and ospA is downregulated. In the current study, using B. burgdorferi cultivated under varying conditions in BSK-H medium, we found that a decrease in pH, in conjunction with increases in temperature (e.g. 34°C or 37°C) and cell density, acted interdependently for the reciprocal expression of ospC and ospA. The lower pH (6.8), which induced the reciprocal expression of ospC and ospA in BSK-H medium, correlated with a drop in pH from 7.4 to 6.8 of tick midgut contents during tick feeding. In addition to ospC and ospA, other genes were found to be regulated in reciprocal fashion. Such genes were either ospC-like (e.g. ospF, mlp-8 and rpoS) (group I) or ospA-like (lp6.6 and p22) (group II); changes in expression occurred at the mRNA level. That the expression of rpoS, encoding a putative stress-related alternative sigma factor (σ(s)), was ospC-like suggested that the expression of some of the group I genes may be controlled through σ(s). The combined results prompt a model that allows for predicting the regulation of other B. burgdorferi genes that may be involved in spirochaete transmission, virulence or mammalian host immune responses.
AB - The paradigm for differential antigen expression in Borrelia burgdorferi, the agent of Lyme disease, is the reciprocal expression of its outer surface (lipo)proteins (Osp) A and C; as B. burgdorferi transitions from its arthropod vector into mammalian tissue, ospC is upregulated, and ospA is downregulated. In the current study, using B. burgdorferi cultivated under varying conditions in BSK-H medium, we found that a decrease in pH, in conjunction with increases in temperature (e.g. 34°C or 37°C) and cell density, acted interdependently for the reciprocal expression of ospC and ospA. The lower pH (6.8), which induced the reciprocal expression of ospC and ospA in BSK-H medium, correlated with a drop in pH from 7.4 to 6.8 of tick midgut contents during tick feeding. In addition to ospC and ospA, other genes were found to be regulated in reciprocal fashion. Such genes were either ospC-like (e.g. ospF, mlp-8 and rpoS) (group I) or ospA-like (lp6.6 and p22) (group II); changes in expression occurred at the mRNA level. That the expression of rpoS, encoding a putative stress-related alternative sigma factor (σ(s)), was ospC-like suggested that the expression of some of the group I genes may be controlled through σ(s). The combined results prompt a model that allows for predicting the regulation of other B. burgdorferi genes that may be involved in spirochaete transmission, virulence or mammalian host immune responses.
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U2 - 10.1046/j.1365-2958.2000.02104.x
DO - 10.1046/j.1365-2958.2000.02104.x
M3 - Article
C2 - 10998177
AN - SCOPUS:0033778628
SN - 0950-382X
VL - 37
SP - 1470
EP - 1479
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 6
ER -