TY - JOUR
T1 - Pacemaker-neuron-dependent disturbance of the molecular clockwork by a Drosophila CLOCK mutant homologous to the mouse Clock mutation
AU - Lee, Euna
AU - Cho, Eunjoo
AU - Kang, Doo Hyun
AU - Jeong, Eun Hee
AU - Chen, Zheng
AU - Yoo, Seung Hee
AU - Kim, Eun Young
N1 - Funding Information:
We thank Paul Hardin for sharing the anti-VRI antibody. Work in the laboratory of E.Y.K. was supported by the National Research Foundation of Korea (NRF) (Grant NRF-2014R1A2A1A11051765) and the Chronic Inflammatory Disease Research Center (Grant NRF-2012R1A5A048183), which was funded by the Korean government. E.C. was supported by the NRF (Grant NRF-2013R1A1A2060533). Work in the laboratory of Z.C. was supported by The Robert A. Welch Foundation (Grant AU-1731) and the NIH/National Institute on Aging (Grant R01 AG045828).Work in the laboratory of S.-H.Y. was supported by the NIH/National Institute of General Medical Sciences (Grant R01 GM114424).
PY - 2016/8/16
Y1 - 2016/8/16
N2 - Circadian clocks are composed of transcriptional/translational feedback loops (TTFLs) at the cellular level. In Drosophila TTFLs, the transcription factor dCLOCK (dCLK)/CYCLE (CYC) activates clock target gene expression, which is repressed by the physical interaction with PERIOD (PER). Here, we show that amino acids (AA) 657-707 of dCLK, a region that is homologous to the mouse Clock exon 19-encoded region, is crucial for PER binding and E-box-dependent transactivation in S2 cells. Consistently, in transgenic flies expressing dCLK with an AA657-707 deletion in the Clock (Clkout) genetic background (p{dClk-Δ};Clkout), oscillation of core clock genes' mRNAs displayed diminished amplitude compared with control flies, and the highly abundant dCLKΔ657-707 showed significantly decreased binding to PER. Behaviorally, the p{dClk-Δ};Clkout flies exhibited arrhythmic locomotor behavior in the photic entrainment condition but showed anticipatory activities of temperature transition and improved free-running rhythms in the temperature entrainment condition. Surprisingly, p{dClk-Δ};Clkout flies showed pacemakerneuron-dependent alterations in molecular rhythms; the abundance of dCLK target clock proteins was reduced in ventral lateral neurons (LNvs) but not in dorsal neurons (DNs) in both entrainment conditions. In p{dClk-Δ};Clkout flies, however, strong but delayedmolecular oscillations in temperature cycle-sensitive pacemaker neurons, such as DN1s and DN2s, were correlated with delayed anticipatory activities of temperature transition. Taken together, our study reveals that the LNv molecular clockwork is more sensitive than the clockwork of DNs to dysregulation of dCLK by AA657-707 deletion. Therefore, we propose that the dCLK/CYC-controlled TTFL operates differently in subsets of pacemaker neurons, which may contribute to their specific functions.
AB - Circadian clocks are composed of transcriptional/translational feedback loops (TTFLs) at the cellular level. In Drosophila TTFLs, the transcription factor dCLOCK (dCLK)/CYCLE (CYC) activates clock target gene expression, which is repressed by the physical interaction with PERIOD (PER). Here, we show that amino acids (AA) 657-707 of dCLK, a region that is homologous to the mouse Clock exon 19-encoded region, is crucial for PER binding and E-box-dependent transactivation in S2 cells. Consistently, in transgenic flies expressing dCLK with an AA657-707 deletion in the Clock (Clkout) genetic background (p{dClk-Δ};Clkout), oscillation of core clock genes' mRNAs displayed diminished amplitude compared with control flies, and the highly abundant dCLKΔ657-707 showed significantly decreased binding to PER. Behaviorally, the p{dClk-Δ};Clkout flies exhibited arrhythmic locomotor behavior in the photic entrainment condition but showed anticipatory activities of temperature transition and improved free-running rhythms in the temperature entrainment condition. Surprisingly, p{dClk-Δ};Clkout flies showed pacemakerneuron-dependent alterations in molecular rhythms; the abundance of dCLK target clock proteins was reduced in ventral lateral neurons (LNvs) but not in dorsal neurons (DNs) in both entrainment conditions. In p{dClk-Δ};Clkout flies, however, strong but delayedmolecular oscillations in temperature cycle-sensitive pacemaker neurons, such as DN1s and DN2s, were correlated with delayed anticipatory activities of temperature transition. Taken together, our study reveals that the LNv molecular clockwork is more sensitive than the clockwork of DNs to dysregulation of dCLK by AA657-707 deletion. Therefore, we propose that the dCLK/CYC-controlled TTFL operates differently in subsets of pacemaker neurons, which may contribute to their specific functions.
KW - CLOCK
KW - Circadian rhythm
KW - Dorsal neuron
KW - Lateral neuron
KW - TTFL
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UR - http://www.scopus.com/inward/citedby.url?scp=84982244616&partnerID=8YFLogxK
U2 - 10.1073/pnas.1523494113
DO - 10.1073/pnas.1523494113
M3 - Article
C2 - 27489346
AN - SCOPUS:84982244616
SN - 0027-8424
VL - 113
SP - E4904-E4913
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 33
ER -