Functional analysis of putative operons in Brugia malayi

Area of Science:

• Molecular Biology
• Genetics
• Parasitology

Background:

• Operons are a prevalent gene organization strategy in model organisms like Caenorhabditis elegans.
• Structural similarities in gene arrangement between C. elegans and Brugia malayi suggested the potential existence of functional operons in this parasitic nematode.

Purpose of the Study:

• To experimentally validate the presence and functionality of operons in Brugia malayi.
• To investigate the regulatory elements involved in Brugia malayi operon function and mRNA processing.

Main Methods:

• Construction of a bicistronic reporter vector containing firefly and renilla luciferase genes.
• Genome-wide survey to identify putative operon gene clusters.
• Reporter gene assays in transfected Brugia malayi embryos to assess promoter activity and intergenic region function.
• Site-directed mutagenesis of U-rich elements within a putative operon.
• Hemi-nested reverse transcriptase-PCR to analyze spliced leader addition in transgenic constructs.

Main Results:

• Two of four tested upstream domains exhibited promoter activity.
• Transfection of constructs containing both promoter and intergenic regions resulted in dual luciferase activity, confirming operon function.
• Mutation of U-rich elements significantly reduced downstream reporter gene expression.
• Transgenic reporter mRNA lacked the native SL1 spliced leader, unlike the endogenous operon mRNA.

Conclusions:

• This study provides definitive evidence for the existence of functional operons in Brugia malayi.
• Specific U-rich elements are implicated in the mRNA maturation process of Brugia malayi operons.
• Differences in spliced leader addition between native and transgenic operons highlight complexities in Brugia malayi gene expression regulation.