Publication details
Timing is everything (unless you knock it down): roles of the circadian clock genes in cockroaches
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| Year of publication | 2025 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | While the core transcriptional–translational feedback loop (TTFL) of the circadian clock (CC) has been well studied, the roles of genes involved in accessory loops remain poorly understood. To address this, we performed functional knockdowns of four such genes—doubletime (dbt), jetlag (jet), fbxl and taiman (tai)—in two evolutionarily distinct cockroach species: Blattella germanica and Periplaneta americana. For comparison, we also silenced two core loop CC genes, bmal and clock. To ensure specificity, at least two independent dsRNA constructs were used per gene. We assessed whole-organism effects by monitoring free-running locomotor activity rhythms (FRP) of individual cockroaches kept under constant darkness for 10 days. Period lengths of knockdown individuals were compared to two control groups: one injected with non-specific dsRNA (LacZ) and one uninjected. Knockdown of clock caused complete arrhythmicity in both species, confirming its essential role in rhythm generation. Silencing bmal led to arrhythmicity in B. germanica, but had no effect in P. americana, suggesting the presence of compensatory mechanisms or alternative regulation. Jet knockdown also produced species-specific results: it disrupted rhythms in B. germanica but not in P. americana, possibly due to the latter’s evolutionary loss of interacting partners such as CRY1. Knockdowns of dbt, fbxl and tai (only in B. germanica) - genes involved in post-translational regulations - significantly lengthened the FRP, indicating conserved roles in period modulation. This study highlights cockroaches as suitable models for analyzing CC regulation at the whole-organism level. Not only are they viable alternatives to the D. melanogaster model with a “canonical” CC, but they also harbor components such as FBXL - absent in most insect but present in mammals - thereby opening new opportunities for comparative chronobiology with potential relevance to human circadian systems. |