Laboratório de Biologia Molecular, Instituto de Ciências Biológicas (ICB), Universidade Federal do Rio Grande (FURG), Av. Itália, Km 8, Rio Grande, RS, 96201-900, Brazil.
Centro de Ciências Computacionais (C3), Universidade Federal do Rio Grande (FURG), Rio Grande, Brazil.
Transgenic Res. 2017 Dec;26(6):739-752. doi: 10.1007/s11248-017-0039-9. Epub 2017 Aug 9.
In the present work it was demonstrated that transgenic Danio rerio overexpressing growth hormone (GH-transgenic) present either altered gene expression at a determined time point, or different expression pattern along the LD cycle, when compared with non-transgenic (NT) animals, in the positive and negative loops of the circadian system. Gene expression of clock paralogs was reduced in GH fish at the beginning of the dark phase, leading to diminished expression amplitude along the LD cycle. Furthermore, although no differences were observed between NT and GH animals for bmal1a and cry2b expression at each time point, only GH fish presented amplitude along the LD cycle. Also, the locomotor activity behavior was evaluated for both groups. GH-transgenic animals presented higher locomotor activity along the whole LD cycle when compared with NT animals. These data suggest that alterations in the gene expression patterns along the LD cycle of the positive and negative loops of the circadian system, could lead to altered locomotor activity behavior in GH-transgenic fish, and GH overexpression could be responsible for these alterations, either affecting the pathways involved in the expression of genes from the circadian system or altering the metabolism.
在本工作中，我们证明了过度表达生长激素的转基因斑马鱼（GH 转基因）与非转基因（NT）动物相比，无论是在正反馈还是负反馈环路中，在特定时间点都表现出基因表达的改变，或者在 LD 周期中表现出不同的表达模式。在暗期开始时，GH 鱼中的生物钟基因的表达减少，导致 LD 周期中表达幅度减小。此外，尽管在每个时间点，NT 和 GH 动物的 bmal1a 和 cry2b 表达都没有差异，但只有 GH 鱼具有 LD 周期中的振幅。同时，我们还评估了两组动物的活动行为。与 NT 动物相比，GH 转基因动物在整个 LD 周期中的活动水平更高。这些数据表明，正反馈和负反馈环路中基因表达模式沿 LD 周期的改变可能导致 GH 转基因鱼活动行为的改变，而 GH 过表达可能是这些改变的原因，这可能是通过影响生物钟系统基因表达途径或改变代谢来实现的。
