Meireles-Filho Antonio C A, da S Rivas Gustavo B, Gesto João S M, Machado Ricardo C, Britto Constança, de Souza Nataly A, Peixoto Alexandre A
Department of Biochemistry and Molecular Biology, Instituto Oswaldo Cruz--Fiocruz, Av. Brasil 4365, Manguinhos, CEP 21045-900, Rio de Janeiro, Brazil.
FEBS Lett. 2006 Jan 9;580(1):2-8. doi: 10.1016/j.febslet.2005.11.031. Epub 2005 Dec 1.
Despite the importance of circadian rhythms in vector-borne disease transmission, very little is known about its molecular control in hematophagous insect vectors. In Drosophila melanogaster, a negative feedback loop of gene expression has been shown to contribute to the clock mechanism. Here, we describe some features of the circadian clock of the sandfly Lutzomyia longipalpis, a vector of visceral leishmaniasis. Compared to D. melanogaster, sandfly period and timeless, two negative elements of the feedback loop, show similar peaks of mRNA abundance. On the other hand, the expression of Clock (a positive transcription factor) differs between the two species, raising the possibility that the different phases of Clock expression could be associated with the observed differences in circadian activity rhythms. In addition, we show a reduction in locomotor activity after a blood meal, which is correlated with downregulation of period and timeless expression levels. Our results suggest that the circadian pacemaker and its control over the activity rhythms in this hematophagous insect are modulated by blood intake.
尽管昼夜节律在病媒传播疾病中具有重要作用，但对于吸血昆虫病媒中昼夜节律的分子控制却知之甚少。在黑腹果蝇中，基因表达的负反馈环已被证明有助于生物钟机制。在此，我们描述了内脏利什曼病病媒长须罗蛉昼夜节律钟的一些特征。与黑腹果蝇相比，反馈环的两个负向元件——罗蛉周期蛋白和无时间蛋白，显示出相似的mRNA丰度峰值。另一方面，生物钟基因（一种正向转录因子）在这两个物种中的表达有所不同，这增加了生物钟基因表达的不同阶段可能与观察到的昼夜活动节律差异相关的可能性。此外，我们发现吸血后运动活动减少，这与周期蛋白和无时间蛋白表达水平的下调相关。我们的结果表明，这种吸血昆虫的昼夜起搏器及其对活动节律的控制受到吸血的调节。
