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Leishmania RNA virus 1-mediated cap-independent translation
J A Maga1, G Widmer, J H LeBowitz
1Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA.
Molecular and Cellular Biology
|September 1, 1995
Summary
Leishmania RNA virus 1 (LRV1) utilizes a cap-independent translation mechanism. Its 5' untranslated region functions as an internal ribosome entry site (IRES), enabling gene expression in Leishmania.
Area of Science:
- Virology
- Molecular Biology
- Parasitology
Background:
- Leishmania RNA viruses (LRV1) are double-stranded RNA viruses found in Leishmania parasites.
- LRV1 lacks 5' cap structures, suggesting a non-canonical translation initiation.
Purpose of the Study:
- To investigate if the 5' untranslated region (UTR) of LRV1 possesses internal ribosome entry site (IRES) activity.
- To explore the potential of LRV1 IRES for gene expression studies in Leishmania.
Main Methods:
- A dicistronic Leishmania expression vector was engineered to place the beta-glucuronidase (GUS) gene downstream of the LRV1 5' UTR.
- Stable transformation of Leishmania major with the construct and measurement of GUS activity.
- Deletion analysis of the LRV1 5' UTR to assess its role in translation.
Main Results:
- High GUS activity was observed in Leishmania expressing the dicistronic transcript.
- Eliminating parts of the 5' UTR significantly reduced GUS activity, with complete elimination abolishing it.
- Absence of trans-spliced transcripts confirmed GUS expression was not due to alternative splicing.
Conclusions:
- The 5' UTR of LRV1 functions as an internal ribosome entry site (IRES).
- This LRV1 IRES element can drive cap-independent gene expression in Leishmania.
- The identified IRES offers a valuable tool for genetic manipulation and gene expression studies in Leishmania species.