Quantification of protein abundance and interaction defines a mechanism for operation of the circadian clock.
Quantification of protein abundance and interaction defines a mechanism for operation of the circadian clock.
复制标题
DOI：
10.7554/elife.73976
复制
发表时间：
2022-03-14
期刊：
影响因子：
7.7
通讯作者：
Loudon ASI
中科院分区：
文献类型：
--
作者：
Koch AA;Bagnall JS;Smyllie NJ;Begley N;Adamson AD;Fribourgh JL;Spiller DG;Meng QJ;Partch CL;Strimmer K;House TA;Hastings MH;Loudon ASI
哺乳动物的生物钟通过DNA结合的循环来控制每日的基因表达。在这里，我们开发了一个定量模型，说明有限的BMAL1蛋白库如何在每天的时间尺度上调节数千个靶位点。我们使用定量成像来追踪外周组织和SCN中内源性标记蛋白的动态变化。我们确定了协调BMAL1 DNA结合的多个节律过程的贡献，包括循环分子丰度，结合亲和力和抑制。我们发现核BMAL1浓度通过异源二聚化决定相应的时钟，并定义了该复合物的DNA停留时间。CLOCK：BMAL1的抑制是通过BMAL1：BMAL1缔合的节律性变化和PER 2：BMAL1之间的高亲和力相互作用实现的，PER 2：BMAL1介导CLOCK：BMAL1从DNA的置换。最后，随机建模揭示了PER：CRY复合物的双重作用，其中增加PER 2：CRY1的浓度促进从基因中去除BMAL1：CLOCK，从而增强移动到新靶位点的能力。
The mammalian circadian clock exerts control of daily gene expression through cycles of DNA binding. Here, we develop a quantitative model of how a finite pool of BMAL1 protein can regulate thousands of target sites over daily time scales. We used quantitative imaging to track dynamic changes in endogenous labelled proteins across peripheral tissues and the SCN. We determine the contribution of multiple rhythmic processes coordinating BMAL1 DNA binding, including cycling molecular abundance, binding affinities, and repression. We find nuclear BMAL1 concentration determines corresponding CLOCK through heterodimerisation and define a DNA residence time of this complex. Repression of CLOCK:BMAL1 is achieved through rhythmic changes to BMAL1:CRY1 association and high-affinity interactions between PER2:CRY1 which mediates CLOCK:BMAL1 displacement from DNA. Finally, stochastic modelling reveals a dual role for PER:CRY complexes in which increasing concentrations of PER2:CRY1 promotes removal of BMAL1:CLOCK from genes consequently enhancing ability to move to new target sites.