Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA.
Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, CT 06511, USA.
Int J Mol Sci. 2022 Mar 24;23(7):3545. doi: 10.3390/ijms23073545.
is a medically important tick that transmits several microbes to humans, including rickettsial pathogen . In nature, these ticks encounter several abiotic factors including changes in temperature, humidity, and light. Many organisms use endogenously generated circadian pathways to encounter abiotic factors. In this study, we provide evidence for the first time to show that modulates the arthropod circadian gene for its transmission to the vertebrate host. We noted a circadian oscillation in the expression of arthropod , , and genes when ticks or tick cells were exposed to alternate 12 h light: 12 h dark conditions. Moreover, significantly modulates the oscillation pattern of expression of these genes. In addition, increased levels of and and decreased expression of Toll and JAK/STAT pathway immune genes such as and respectively, were noted during transmission from ticks to the vertebrate host. RNAi-mediated knockdown of gene expression in ticks resulted in the reduced expression of and that increased bacterial transmission from ticks to the murine host. Furthermore, -deficient ticks fed late and had less engorgement weights. These results indicate an important role for circadian modulation of tick gene expression that is critical for arthropod blood feeding and transmission of pathogens from vector to the vertebrate host.
是一种医学上重要的蜱虫，能将几种微生物传播给人类，包括立克次体病原体。在自然界中，这些蜱虫会遇到几种非生物因素，包括温度、湿度和光照的变化。许多生物利用内源性生成的昼夜节律途径来应对非生物因素。在这项研究中，我们首次提供证据表明，调节节肢动物的昼夜节律基因，使其能够传播给脊椎动物宿主。当蜱虫或蜱细胞暴露于交替的 12 小时光照：12 小时黑暗条件下时，我们注意到节肢动物 、 、 和 基因的表达呈现出昼夜节律性波动。此外， 显著调节这些基因表达的波动模式。此外，在从蜱虫向脊椎动物宿主传播过程中， 水平升高和 Toll 和 JAK/STAT 通路免疫基因如 和 的表达降低，分别为 和 。在蜱虫中用 RNAi 介导的 基因表达敲低导致 和 的表达减少，从而增加了从蜱虫向鼠类宿主传播的细菌数量。此外，缺乏 的蜱虫进食较晚，且吸血后体重增加较少。这些结果表明，昼夜节律调节蜱虫基因表达对节肢动物吸血和病原体从媒介传播到脊椎动物宿主至关重要。
