ISSN:
1550-7408
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Pneumocystis carinii, a major opportunistic lung pathogen of AIDS patients, is found in a number of mammals and is proposed to be a member of the fungi. In this work, several members of the highly conserved HSP70 multigene family were characterized from rat-derived P. carinii. Previously, we reported characterization of the ER resident HSP70 homolog known as BiP from prototype (P. c. carinii) and variant (P. c. rattus) strains of the organism. We report here, from P. c. carinii, characterization of Pcsal, an HSP70 homolog that encodes a cognate/stress-induced HSP70 homolog of the SSA subfamily in Saccharomyces cerevisiae. We also identify from both rat strains and from a human isolate of P. carinii (P.c. hominis), a third set of HSP70 homologs that apparently encode a ribosome-associated cytoplasmic HSP70 homologous to the S. cerevisiae SSB subfamily. Our data indicate that Pcsal mRNA, like Pcbip mRNA, bears an intron in the 5′ untranslated region, is induced by heat shock, and suggest that this gene undergoes alternative transcription and splicing. The SSB homologs display significant sequence heterogeneity between P. carinii source strains, supporting the genetic divergence and likely speciation of P. carinii isolates within and between host species. Phylogenetic analysis with the PcSAl protein supports inclusion of P. carinii among the higher fungi.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1550-7408.1998.tb04554.x
