Does the precision of a biological clock depend upon its period? Effects of the duper and tau mutations in Syrian hamsters.
Does the precision of a biological clock depend upon its period? Effects of the duper and tau mutations in Syrian hamsters.
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DOI：
10.1371/journal.pone.0036119
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Bittman EL
中科院分区：
文献类型：
--
作者：
Bittman EL
改变产生昼夜节律的反馈回路的突变可以洞察它们对扰动的不敏感性(稳健性)和它们的周期一致性(精度)。我使用两种不同的突变Duper和tau研究了叙利亚仓鼠的内源性周期、活动和休息(τDD、α和ρ)之间的关系，这两种突变都加快了生物钟。我产生了8个品系的仓鼠，它们在所有组合中都是tau、duper和野生型等位基因的纯合或杂合。这些菌株的活性起始点的内生周期在17.94±0.04~24.13±0.04h之间，与预测相反，周期的变异性与其绝对值无关：当活性起始点和顶相作为阶段标记时，所有菌株都表现出相似的τDD变异性。活动偏移量的τDD比起始值的变化更大，但不同基因型之间的差异也很小。周期变异和精密度与τDD在任何菌株内均不相关，只有当所有菌株被考虑在一起时才具有弱相关性。只有在两种突变纯合的动物(超级仓鼠)中，周期变异和精确度都会降低。不同品系的节律幅度不同，且与τ、DD和精度呈正相关。各基因型α与ρ均呈负相关。这证实了这样一种预期，即主观昼夜持续时间的偏差应该相互抵消，以保存昼夜节律，即使维持能量储备的动态平衡预测，较长的活动或休息间隔将伴随较长的休息或活动持续时间。雌性仓鼠始终表现出较大的活动起始期和顶峰期以及α的变异性，但偏移期的变异性仅在超级大仓鼠中存在性别差异。尽管τDD的不同基因型之间存在差异，但ρ与前一种α的相关性始终强于后一种。
Mutations which alter the feedback loops that generate circadian rhythms may provide insight into their insensitivity to perturbation robustness) and their consistency of period (precision). I examined relationships between endogenous period, activity and rest (τDD, α and ρ) in Syrian hamsters using two different mutations, duper and tau, both of which speed up the circadian clock. I generated 8 strains of hamsters that are homozygous or heterozygous for the tau, duper, and wild type alleles in all combinations. The endogenous period of activity onsets among these strains ranged from 17.94+0.04 to 24.13±0.04 h. Contrary to predictions, the variability of period was unrelated to its absolute value: all strains showed similar variability of τDD when activity onsets and acrophase were used as phase markers. The τDD of activity offsets was more variable than onsets but also differed little between genotypes. Cycle variation and precision were not correlated with τDD within any strain, and only weakly correlated when all strains are considered together. Only in animals homozygous for both mutations (super duper hamsters) were cycle variation and precision reduced. Rhythm amplitude differed between strains and was positively correlated with τDD and precision. All genotypes showed negative correlations between α and ρ. This confirms the expectation that deviations in the duration of subjective day and night should offset one another in order to conserve circadian period, even though homeostatic maintenance of energy reserves predicts that longer intervals of activity or rest would be followed by longer durations of rest or activity. Females consistently showed greater variability of the period of activity onset and acrophase, and of α, but variability of the period of offset differed between sexes only in super duper hamsters. Despite the differences between genotypes in τDD, ρ was consistently more strongly correlated with the preceding than the succeeding α.
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影响因子：
2.9
作者：
Hague, JFE;Gilbert, SS;Dawson, D
通讯作者：
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作者：
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DOI：
10.1073/pnas.0604511103
发表时间：
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影响因子：
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作者：
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