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Leishmania major : Cell type dependent distribution of a 43 kDa antigen related to silent information regulatory‐2 protein family
Author(s) -
Zemzoumi Khalid,
Sereno Denis,
Francois Céline,
Guilvard Eliane,
Lemesre JeanLoup,
Oualssi Ali
Publication year - 1998
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/s0248-4900(98)80020-8
Subject(s) - biology , antigen , leishmania , immunoprecipitation , western blot , amastigote , cytoplasm , kinetoplastida , parasite hosting , trypanosoma cruzi , microbiology and biotechnology , antibody , gene , biochemistry , genetics , immunology , protozoal disease , world wide web , computer science , malaria
In previous studies we have characterized several Leishmania major polypeptides and showed that one member of this group ( Lm SIR2rp) shared significant homology to silent information regulator 2 (SIR2) of Saccharomyces cerevisiae , a protein playing a role in both telomeric and mating type loci repression in these organisms. In the present study, by using molecular and immunological approaches, we could identify Lm SIR2rp homologues in different Leishmania species and developmental stages ( eg logarithmic (LP) and stationary phase promastigotes (SP) and amastigotes). The reactive antigen was also detected in Trypanosoma cruzi extracts. Surprisingly, immunofluorescence assays revealed that Lm SIR2rp is associated mainly with cytoplasmic granules of different sizes and numbers depending on the life stage of the parasite used. No reactivity was observed in the nucleus, in agreement with the Western blot showing an absence of immunoreactivity of anti‐ Lm SIR2rp immune serum against parasite nuclear extracts. Furthermore, immunoprecipitation of [ 35 S]methionine‐labeled promastigote antigens after pulse chase experiments, using anti‐ Lm SIR2rp fusion protein antibodies, showed that the protein is among parasite excreted‐secreted antigens (ESA). Moreover, immunoflurescence assays conducted with short time incubations of either purified Lm SIR2rp or viable promastigotes with murine macrophages, revealed that Lm SIR2rp could be bound to the macrophage surface. The unexpected cytoplasmic localization of Lm SIR2rp and its presence in ESA may suggest a new mode of action for silent information regulatory factor homologues.