Three isoforms of Brugia malayi daf-16 activate a reporter gene in cultured HepG2 cells.

We hypothesize that infective stage molting in the parasitic nematode Brugia malayi is regulated by an ortholog of the Caenorhabditis elegansdaf-16 gene, similar to the role of daf-16 in dauer formation and recovery. We confirmed the gene structure of three isoforms of B. malayi daf-16 (Bma-daf-16) and generated cell culture expression constructs for each. In luciferase assays using transfected HepG2 cells, all three isoforms activated a luciferase reporter gene regulated by six DAF-16 binding sites, although Bma- DAF-16a showed lower activation ability than Bma- DAF-16b and Bma- DAF-16c. These results support our hypothesis that Bma-daf-16 functions similarly to C. elegansdaf-16 .