Abstract
Leishmania donovani, a protozoan parasite, causes visceral disease in humans. To identify genes that control growth, we have isolated for the first time in the order Kinetoplastida a gene encoding for centrin from L. donovani. Centrin is a calcium-binding cytoskeletal protein essential for centrosome duplication or segregation. Protein sequence similarity and immunoreactivity confirmed that Leishmania centrin is a homolog of human centrin 2. Immunofluorescence analysis localized the protein in the basal body. Calcium binding analysis revealed that its C-terminal Ca(2+) binding domain binds 16-fold more calcium than the N-terminal domain. Electrophoretic mobility shift of centrin treated with EGTA and abrogation of the shift in its mutants lacking a Ca(2+) binding site suggest that Ca(2+) binding to these regions may have a role in the protein conformation. The levels of centrin mRNA and protein were high during the exponential growth of the parasite in culture and declined to a low level in the stationary phase. Expression of N-terminal-deleted centrin in the parasite significantly reduces its growth rate, and it was found that significantly more cells are arrested in the G(2)/M stage than in control cells. These studies indicate that centrin may have a functional role in Leishmania growth.
Highlights
Leishmania donovani, a protozoan parasite and a member of the order Kinetoplastida, is the causative agent of visceral leishmaniasis in humans worldwide
Cloning and Sequence Analysis of the L. donovani Centrin Gene—We used an arbitrarily primed polymerase chain reaction (AP-PCR) approach, as previously described [5], to isolate genes from L. donovani that are differentially expressed during the growth and differentiation of this parasite
The cloned gene, L. donovani centrin (LdCEN), from the L. donovani parasite is more homologous to centrin than the other closely related Ca2ϩ binding EF-hand proteins such as calmodulins
Summary
43253–43261, 2001 Printed in U.S.A. Expression of a Mutant Form of Leishmania donovani Centrin Reduces the Growth of the Parasite*. Expression of N-terminal-deleted centrin in the parasite significantly reduces its growth rate, and it was found that significantly more cells are arrested in the G2/M stage than in control cells These studies indicate that centrin may have a functional role in Leishmania growth. Leishmania donovani, a protozoan parasite and a member of the order Kinetoplastida, is the causative agent of visceral leishmaniasis in humans worldwide. The parasites of the Kinetoplastida are responsible for a wide variety of diseases affecting humans, animals, and plants [15] Members of this group have been considered to be one of the earliest eukaryotes, developing conventional organelles, but sometimes with extreme features rarely seen in other organisms [15]. L. donovani Centrin gene and expressing such truncated proteins in the parasites to test their potential role in the growth of the parasite
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
