Effect of silencing the clock gene period in the Chagas disease vector Triatoma infestans

Abstract

The Chagas disease vector Triatoma infestans shows daily rhythms controlled by the biological clock genes. The RNA interference (RNAi) is a specific silencing mechanism that disrupts the gene expression. In order to analyze the effect of silencing the clock gene period (per) in T. infestans, RNAi protocols with different feeding regimens were used and its daily expression profile was analyzed in the nervous tissue.

RNAi of the gene per and RNAi of the control gene β-Lactamase (β-Lac) were injected into adult female and male individuals. The dissections were performed every 6 hr over a 24-hour period and the time of day was reported as Zeitgeber Time (ZT). Samples consisted of groups of 3 individuals and 3 biological replicates were analyzed for each ZT. The expression of per gene was determined by Retrotranscription-Real Time PCR (RT-qPCR). The results were analyzed by One-way ANOVA test followed by the Bonferroni test (multiple comparison).

Silencing of per gene in T. infestans males and females showed a significant decrease of expression at transcriptional level in the group injected with the RNAi of per  gene compared to the levels found in the control groups non-injected and injected with RNAi for β-Lac gene . The feeding regimens used in the protocols did not significantly affect the level of interference. On the other hand, the silencing of per gene reduced its expression in a half in all the ZTs analyzed and was not observed the characteristic daily variation at the transcriptional level that this clock gene presents.

The results obtained allowed to establish that the silencing of per gene was effective in both males and females and was not affected by the feeding regimens used in the interference protocols.