Functional analysis of the 5′ untranslated region of the phosphoglutamase 2 transcript in Plasmodium falciparum

• Serial deletions of 5′ UTR of a malarial parasite housekeeping gene created.
• Reporter cassettes utilise endogenous transcription start and stop sites.
• 5′ UTR deletions have minimal effect on steady-state mRNA levels.
• Longer deletions of 5′UTR affect efficiency of translation.
• Deletions have no effect on temporal control of transcription or translation.

Plasmodium falciparum transcripts contain long untranslated regions (UTR), with some of the longest in any eukaryote that uses monocistronic transcription. Owing to the extreme AT nucleotide bias within the intergenic regions that encode these UTR, attempts to characterise how they are apportioned over genes and to describe their contribution to the absolute and temporal control of gene expression have been limited. Here we describe a study using a typical house-keeping gene that encodes phosphoglutamase 2 (PFD0660w), whose expression is subject to developmentally linked control during intraerythrocytic development. We show that deletion of a significant proportion (80%) of the predicted 5′ UTR has no apparent effect on the developmentally linked expression of a luciferase reporter cassette. Further, serial deletions reveal that whilst the absolute level of transcription is unaffected when up to 50% of the predicted 5′ UTR is removed, the subsequent efficiency of translation is affected. These data provide key insights into the interplay of transcriptional and post-transcriptional mechanisms in the control of gene expression in this important human pathogen.

This study explores the interplay of transcriptional and post-transcriptional mechanisms in the absolute and temporal control of gene expression in the human malarial parasite.Figure optionsDownload as PowerPoint slide