Biology Center, Academy of Sciences of the Czech Republic, 37005 Ceske Budejovice, Czech Republic.
Proc Natl Acad Sci U S A. 2013 Mar 12;110(11):4416-21. doi: 10.1073/pnas.1217060110. Epub 2013 Feb 26.
In temperate regions, the shortening day length informs many insect species to prepare for winter by inducing diapause. The adult diapause of the linden bug, Pyrrhocoris apterus, involves a reproductive arrest accompanied by energy storage, reduction of metabolic needs, and preparation to withstand low temperatures. By contrast, nondiapause animals direct nutrient energy to muscle activity and reproduction. The photoperiod-dependent switch from diapause to reproduction is systemically transmitted throughout the organism by juvenile hormone (JH). Here, we show that, at the organ-autonomous level of the insect gut, the decision between reproduction and diapause relies on an interaction between JH signaling and circadian clock genes acting independently of the daily cycle. The JH receptor Methoprene-tolerant and the circadian proteins Clock and Cycle are all required in the gut to activate the Par domain protein 1 gene during reproduction and to simultaneously suppress a mammalian-type cryptochrome 2 gene that promotes the diapause program. A nonperiodic, organ-autonomous feedback between Par domain protein 1 and Cryptochrome 2 then orchestrates expression of downstream genes that mark the diapause vs. reproductive states of the gut. These results show that hormonal signaling through Methoprene-tolerant and circadian proteins controls gut-specific gene activity that is independent of circadian oscillations but differs between reproductive and diapausing animals.
在温带地区，较短的日照时间会促使许多昆虫物种通过诱导休眠来为冬季做准备。欧洲绿斑芫菁的成虫休眠涉及生殖暂停，伴随着能量储存、代谢需求减少以及为抵御低温做准备。相比之下，不休眠的动物会将营养能量用于肌肉活动和繁殖。由昆虫激素（JH）介导的光周期依赖性从休眠到繁殖的转变在整个生物体中系统地传递。在这里，我们表明，在昆虫肠道的器官自主水平上，生殖与休眠之间的决策依赖于 JH 信号和生物钟基因之间的相互作用，而这些作用独立于日常周期。JH 受体 Methoprene-tolerant 和生物钟蛋白 Clock 和 Cycle 都在肠道中被需要，以在生殖期间激活 Par 结构域蛋白 1 基因，并同时抑制促进休眠程序的哺乳动物型隐色素 2 基因。然后，Par 结构域蛋白 1 和隐色素 2 之间的非周期性、器官自主反馈协调了下游基因的表达，这些基因标记了肠道的休眠与生殖状态。这些结果表明，通过 Methoprene-tolerant 和生物钟蛋白的激素信号控制了肠道特异性基因活性，这种活性独立于生物钟波动，但在生殖和休眠动物之间存在差异。
