Da. Russian et al., Characterization of a multicopy family of genes encoding a surface-expressed serine endoprotease in rat Pneumocystis carinii, P ASS AM PH, 111(4), 1999, pp. 347-356
Citations number
22
Categorie Soggetti
General & Internal Medicine","Medical Research General Topics
Journal title
PROCEEDINGS OF THE ASSOCIATION OF AMERICAN PHYSICIANS
A unique family of genes encoding serine endoproteases related to the Sacch
aromyces cerevisiae serine endoprotease kexin was identified in Pneumocysti
s carinii. Unlike previously described serine endoprotease genes that are s
ingle copies, multiple copies of the P. carinii serine endoprotease are dis
tributed throughout the genome. The proteins predicted by these variant gen
es demonstrate sequence variability, but they retain the conserved active s
ites associated with endoprotease activity. The serine endoprotease was loc
alized to the organism surface by immunohistochemical and immunofluorescenc
e studies and to the electron lucent layer of the cyst wall by immunoelectr
on microscopy. The findings of multiple copies of the serine endoprotease g
ene in the P. carinii genome, and its localization to the cell surface, sug
gest that this protease plays an important role in the biology of P. carini
i and that antigenic variation of the surface-expressed serine endoprotease
may be a strategy for immune evasion. P. carinii serine endoprotease provi
des a novel target for chemotherapeutic and immune-based approaches to the
treatment of P. carinii pneumonia.