The
m>Rickettsiales Ehrlichia ruminantiumm> (ER) is the causative agent of heartwater, a fatal tick-borne disease of livestock in sub-Saharan Africa and in the Caribbean, posing strong econo
mical constraints to livestock production. In an atte
mpt to identify the
most pro
minent proteins expressed by this bacteriu
m, especially those encoded by the
major antigenic protein 1 (
m>map1m>)
multigene fa
mily, a proteo
me
map of ER cultivated in endothelial cells was constructed by using two di
mensional gel electrophoresis co
mbined with
mass spectro
metry. A
mong the sixty-four spots detected, we could identify only four proteins fro
m the MAP1-fa
mily; the other proteins detected were
mainly related to energy, a
mino acid and general
metabolis
m (26%), to protein turnover, chaperones and survival (21%) and to infor
mation processes (14%) or classified as hypothetical proteins (23%).
Additional studies on MAP1-family protein using immunochemical labeling also revealed that these proteins are differentially expressed along the bacterium life cycle, presenting different structural organization. Interestingly, when infectious elementary bodies (EBs) are released from host cells, MAP1 appears to be organized in SDS and heat-resistant dimers and trimers stabilized by disulfide bridges.
Overall, the results presented herein not only reveal the first partial proteome map of ER but provide new insights on the expression ER MAP1-family proteins in host endothelial cells.