Early response gene expression during differentiation of cultured Leishmania donovani.
The promastigote form of the unicellular parasite, Leishmania donovani, must differentiate into the amastigote form to establish an infection in a mammalian host. Identification of genes whose expression changes during differentiation could help reveal mechanisms of Leishmania gene regulation and identify targets for controlling the diseases caused by this human pathogen. Two genomic clones were isolated, P9 that is more highly expressed in promastigotes than in axenic amastigotes and A14 that is preferentially expressed in axenic amastigotes. Analysis of the DNA sequences revealed open reading frames that would encode 55.5 kDa and 100 kDa proteins, respectively, with no homology to known proteins. The mRNA level for these genes during 24 h time courses of parasite differentiation in culture was compared to two genes known to be differentially expressed, c-lpk2 and mkk. Changes in RNA level occurred within 2 h for each gene and continued in advance of morphological changes. The expression levels of these four genes in axenic amastigotes correlated with results from animal-derived parasites.
Duncan
R
R
Laboratory of Bacterial, Parasitic and Unconventional Agents, FDA/CBER, Bethesda, MD 20892, USA. duncan@cber.fda.gov
Alvarez
R
R
Jaffe
C L
CL
Wiese
M
M
Klutch
M
M
Shakarian
A
A
Dwyer
D
D
Nakhasi
H L
HL
D000818:Animals; D001483:Base Sequence; D003470:Culture Media; D016054:DNA, Protozoan / Q000032:analysis; D018507:Gene Expression Regulation, Developmental; D017125:Genes, Protozoan; D007893:Leishmania donovani / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D016053:RNA, Protozoan / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
D003470:Culture Media; D016054:DNA, Protozoan; D012333:RNA, Messenger; D016053:RNA, Protozoan