Abstract |
Leishmanial parasites routinely undergo cyclic differentiation from promastigotes to amastigotes during their life cycle. This process involves both morphological and macromolecular changes. To study such changes, we used a axenic culture system which permits the continuous generation and cycling of Leishmania donovani from promastigotes to 'amastigotes' in vitro. cDNA libraries were constructed from poly(A)+ RNA isolated from both the pro- and amastigote forms. Using differential cDNA hybridization techniques, 3 unique cDNAs clones (P17, A41 and A45) were isolated from the amastigote library. To assess whether these clones were differentially expressed by the pro-or 'amastigotes' forms, they were hybridized to RNA isolated from each of these parasite forms in Northern and slot-blots. Results of these analyses showed that 'amastigotes' had approx. 2-fold higher levels of the A41 and A45 RNAs compared to the promastigotes. Conversely, promastigotes showed approx. 2-fold higher levels of the P17 RNA than 'amastigotes'. Nucleotide sequence analysis and comparison with those in Gene bank, revealed that the 3 cDNAs represent unique leishmanial genes. Comparison of the deduced amino acid sequences revealed that P17 open reading frame (ORF) had significant similarity with a soybean ribosomal protein S11; A41 ORF with a Bacillus subtilis spore germination gene (gerC) and A45 ORF with yeast stress-inducible protein (STI1). It is of interest to note that, of the 3 cDNAs identified, the A45-encoded protein was recognized by sera from patients with clinically active visceral leishmaniasis and was encoded by a single copy gene.
|
Authors | M Joshi, D M Dwyer, H L Nakhasi |
Journal | Molecular and biochemical parasitology
(Mol Biochem Parasitol)
Vol. 58
Issue 2
Pg. 345-54
(Apr 1993)
ISSN: 0166-6851 [Print] Netherlands |
PMID | 8479459
(Publication Type: Journal Article)
|
Chemical References |
- DNA, Protozoan
- RNA, Messenger
- RNA, Protozoan
|
Topics |
- Amino Acid Sequence
- Animals
- Cloning, Molecular
- DNA, Protozoan
(genetics)
- Gene Expression
- Genes, Protozoan
- Humans
- Leishmania donovani
(genetics, growth & development)
- Leishmaniasis, Visceral
(parasitology)
- Molecular Sequence Data
- Phenotype
- Protein Biosynthesis
- RNA, Messenger
(genetics)
- RNA, Protozoan
(genetics)
- Transcription, Genetic
|