Spoelstra K, Oklejewicz M, Daan S
Zoological Laboratory, Biological Center, University of Groningen, Haren, The Netherlands.
J Biol Rhythms. 2002 Dec;17(6):520-5. doi: 10.1177/0748730402238234.
Mice mutant for the Clock gene display abnormal circadian behavior characterized by long circadian periods and a tendency to become rapidly arrhythmic in constant darkness (DD). To investigate whether this result is contingent on the absence of light, the authors studied the circadian behavior of homozygous Clock mutant mice under conditions of both constant light and DD. Fourteen of 15 Clock/Clock mice stayed rhythmic in constant light of 70 to 170 lux, where 10 of 15 wild-type mice became arrhythmic. In contrast, only 5 of 15 Clock/ Clock mice and 15 of 15 wild-type mice remained rhythmic after 60 cycles when released in DD (dim red light of < 1.5 lux) after 8 days of entrainment. The restoration of self-sustained rhythmicity by the Clock allele cannot be attributed to reduced sensitivity of the system to light It underscores the fact that self-sustainment is not a secure guide to functional organization.
Clock基因发生突变的小鼠表现出异常的昼夜节律行为，其特征为昼夜周期延长，并且在持续黑暗（DD）环境中容易迅速失去节律。为了研究这一结果是否取决于光照的缺失，作者研究了纯合Clock突变小鼠在持续光照和DD条件下的昼夜节律行为。15只Clock/Clock小鼠中有14只在70至170勒克斯的持续光照下保持节律性，而15只野生型小鼠中有10只失去了节律性。相比之下，在经过8天的同步化训练后，于DD（<1.5勒克斯的暗红色光）环境中释放60个周期后，15只Clock/Clock小鼠中只有5只以及15只野生型小鼠中的15只仍保持节律性。Clock等位基因恢复自我维持的节律性并非归因于该系统对光的敏感性降低。这突出了一个事实，即自我维持并非功能组织的可靠指标。
