Genome-wide gene expression profiling analysis of Leishmania major and Leishmania infantum developmental stages reveals substantial differences between the two species.
BACKGROUND
Leishmania parasites cause a diverse spectrum of diseases in humans ranging from spontaneously healing skin lesions (e.g., L. major) to life-threatening visceral diseases (e.g., L. infantum). The high conservation in gene content and genome organization between Leishmania major and Leishmania infantum contrasts their distinct pathophysiologies, suggesting that highly regulated hierarchical and temporal changes in gene expression may be involved.


RESULTS
We used a multispecies DNA oligonucleotide microarray to compare whole-genome expression patterns of promastigote (sandfly vector) and amastigote (mammalian macrophages) developmental stages between L. major and L. infantum. Seven per cent of the total L. infantum genome and 9.3% of the L. major genome were differentially expressed at the RNA level throughout development. The main variations were found in genes involved in metabolism, cellular organization and biogenesis, transport and genes encoding unknown function. Remarkably, this comparative global interspecies analysis demonstrated that only 10-12% of the differentially expressed genes were common to L. major and L. infantum. Differentially expressed genes are randomly distributed across chromosomes further supporting a posttranscriptional control, which is likely to involve a variety of 3'UTR elements.


CONCLUSIONS
This study highlighted substantial differences in gene expression patterns between L. major and L. infantum. These important species-specific differences in stage-regulated gene expression may contribute to the disease tropism that distinguishes L. major from L. infantum.
Research Centre in Infectious Diseases, CHUL Research Centre and Department of Medical Biology, Faculty of Medicine, Laval University, Quebec, Canada. annie.rochette@crchul.ulaval.ca
Annie
A
Rochette
Frédéric
F
Raymond
Jean-Michel
JM
Ubeda
Martin
M
Smith
Nadine
N
Messier
Sébastien
S
Boisvert
Philippe
P
Rigault
Jacques
J
Corbeil
Marc
M
Ouellette
Barbara
B
Papadopoulou
D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D002460:Cell Line; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018503:Genome, Protozoan; D006801:Humans; D018314:Leishmania infantum / Q000235:genetics* / Q000254:growth & development*; D018320:Leishmania major / Q000235:genetics* / Q000254:growth & development*; D008018:Life Cycle Stages; D051379:Mice; D008805:Mice, Inbred A; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000302:isolation & purification; D016053:RNA, Protozoan / Q000302:isolation & purification; D018626:Retroelements; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity
D020413:3' Untranslated Regions; D012333:RNA, Messenger; D016053:RNA, Protozoan; D018626:Retroelements