Laboratory of Systems Genetics, Systems Biology Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
Bioinformatics and Computational Biology Core, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
J Biol Rhythms. 2021 Jun;36(3):239-253. doi: 10.1177/0748730420975946. Epub 2020 Dec 4.
The endogenous circadian period of animals and humans is typically very close to 24 h. Individuals with much longer circadian periods have been observed, however, and in the case of humans, these deviations have health implications. Previously, we observed a line of with a very long average period of 31.3 h for locomotor activity behavior. Preliminary mapping indicated that the long period did not map to known canonical clock genes but instead mapped to multiple chromosomes. Using RNA-Seq, we surveyed the whole transcriptome of fly heads from this line across time and compared it with a wild-type control. A three-way generalized linear model revealed that approximately two-thirds of the genes were expressed differentially among the two genotypes, while only one quarter of the genes varied across time. Using these results, we applied algorithms to search for genes that oscillated over 24 h, identifying genes not previously known to cycle. We identified 166 differentially expressed genes that overlapped with a previous Genome-wide Association Study (GWAS) of circadian behavior, strongly implicating them in the long-period phenotype. We tested mutations in 45 of these genes for their effect on the circadian period. Mutations in (), , and had significant effects on the circadian period, with seven of these mutations increasing the circadian period of locomotor activity behavior. Genetic rescue of mutant restored the circadian period to wild-type levels, suggesting it has a critical role in determining period length in constant darkness.
动物和人类的内源性昼夜周期通常非常接近 24 小时。然而，已经观察到昼夜周期长很多的个体，而在人类中，这些偏差与健康有关。此前，我们观察到一个具有非常长的平均活动周期（31.3 小时）的品系。初步定位表明，长周期不与已知的经典生物钟基因映射，而是映射到多个染色体上。使用 RNA-Seq，我们在整个时间范围内调查了来自该品系的果蝇头部的整个转录组，并将其与野生型对照进行比较。三向广义线性模型表明，大约三分之二的基因在两种基因型之间表达差异，而只有四分之一的基因随时间变化。利用这些结果，我们应用算法搜索在 24 小时内振荡的基因，鉴定以前不知道循环的基因。我们鉴定了 166 个差异表达的基因，这些基因与之前的昼夜行为全基因组关联研究 (GWAS) 重叠，强烈表明它们与长周期表型有关。我们测试了这些基因中的 45 个突变对昼夜周期的影响。突变 （）、（）和 （）对昼夜周期有显著影响，其中 7 个突变增加了运动行为的昼夜周期。突变体 的遗传修复将昼夜周期恢复到野生型水平，表明它在决定黑暗中周期长度方面起着关键作用。
