Premium
A developmentally regulated cysteine proteinase gene of Leishmania mexicana
Author(s) -
Mottram Jeremy C.,
Robertson Colin D.,
Coombs Graham H.,
Barry J. David
Publication year - 1992
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1992.tb01365.x
Subject(s) - biology , leishmania mexicana , amastigote , gene , trypanosoma brucei , antiserum , leishmania , microbiology and biotechnology , peptide sequence , cysteine , western blot , biochemistry , amino acid , leishmania major , northern blot , gene expression , parasite hosting , genetics , enzyme , antibody , world wide web , computer science
Summary We have isolated a gene encoding a previously unreported class of trypanosomatid cysteine proteinase (CP) from the protozoan parasite Leishmania mexicana. The single‐copy gene ( Imcpa ) has several unusual features that distinguish it from CP genes cloned from the related species Trypanosoma brucei and Trypanosoma cruzi. These include a shorter C ‐terminal extension of only 10 amino acids and a three‐amino‐acid insertion, GlyValMet, close to the predicted N ‐terminus of the mature protein. Northern blot analysis showed that the gene is expressed in all life‐cycle stages but at higher levels in the amastigote stage in the mammal and in stationary phase promastigote cultures which contain the infective meta‐cyclic form of the parasite. A precursor protein of 38 kDa was detected in amastigotes and stationary phase promastigotes with antisera specific to the LmCPa pro‐region, but was barely detectable in early log‐phase promastigotes. Anti‐central domain antisera recognized the 38 kDa precursor and 24 and 27 kDa proteins. The major CPs of L. mexicana amastigotes, previously designated types A, B and C, were not detected with the antisera, suggesting that the gene codes for a previously uncharacterized CP in L. mexicana. The 24 kDa protein detected by the antiserum has no activity towards gelatin but apparently hydrolyses the peptide substrate BzPhe‐ValArgAMC. The relative levels of the 24 and 27 kDa proteins vary between the different life‐cycle stages. The results indicate that expression of this CP is regulated at both the RNA and protein level.