We tested whether the human Clock (hClock) gene, one of the essential components of the circadian oscillator, is implicated in the vulnerability to delayed sleep phase syndrome (DSPS) and non-24-hour sleep-wake syndrome (N-24). Screening in the entire coding region of the hClock gene with PCR amplification revealed three polymorphisms, of which two predicted the amino acid substitutions R533Q and H542R. The frequencies of the R533Q and H542R alleles in patients with DSPS or N-24 were very low and not significantly different from those in control subjects. A T3111C polymorphism in the 3'-untranslated region of hClock, which had been reportedly associated with morning or evening preference for activity, was also investigated; the results showed that the 3111C allele frequency decreased in DSPS. Polymorphisms in the coding region of the hClock gene are unlikely to play an important role in the development of DSPS or N-24. The possible contribution of the T3111C polymorphism to DSPS susceptibility should be studied further.
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http://dx.doi.org/10.1016/s0165-1781(02)00006-9 | DOI Listing |
Proc Natl Acad Sci U S A
October 2019
School of Chemistry, University of Bristol, BS8 1TS Bristol, United Kingdom;
The circadian clock is an endogenous time-keeping system that is ubiquitous in animals and plants as well as some bacteria. In mammals, the clock regulates the sleep-wake cycle via 2 basic helix-loop-helix PER-ARNT-SIM (bHLH-PAS) domain proteins-CLOCK and BMAL1. There is emerging evidence to suggest that heme affects circadian control, through binding of heme to various circadian proteins, but the mechanisms of regulation are largely unknown.
View Article and Find Full Text PDFExp Mol Med
December 2018
Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea.
Bmal1 is one of the key molecules that controls the mammalian molecular clock. In humans, two isoforms of Bmal1 are generated by alternative RNA splicing. Unlike the extensively studied hBmal1b, the canonical form of Bmal1 in most species, the expression and/or function of another human-specific isoform, hBmal1a, are poorly understood.
View Article and Find Full Text PDFOncol Lett
June 2018
Department of Gastrointestinal Surgery, Jingzhou Central Hospital, Jingzhou, Hubei 434020, P.R. China.
The present study aimed to observe the expression of circadian gene clock circadian regulator () in ovarian cancer cells and the effects of circadian gene on cis-dichlorodiamine platinum (cisplatin) resistance in ovarian cancer cells. The expression of mRNA and protein in cisplatin-sensitive A2780 and cisplatin-resistant CP70 cells were detected by quantitative polymerase chain reaction and western blot assay. Cisplatin-sensitive A2780 and cisplatin-resistant CP70 cells were treated with different concentrations of cisplatin for 48 h, and the expression of hCLOCK protein in the two types of cells was detected by western blot assay.
View Article and Find Full Text PDFMol Med Rep
September 2017
Department of Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China.
An abundance of studies has demonstrated that disruption of circadian rhythms is one of the factors that may contribute to the initiation and development of human colorectal carcinomas (CRCs). Recently, microRNA‑124 has been demonstrated to suppress tumor growth or metastasis of CRCs. However, the mechanisms of cross‑talk between microRNA‑124 (miR‑124) and circadian rhythms in the regulation of CRCs are poorly understood.
View Article and Find Full Text PDFInt J Oncol
June 2017
Department of Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China.
Recent studies have shown that disruption of the circadian rhythm was one of the endogenous factors contributing to tumorigenesis of various human malignancies, including colorectal cancer (CRC). However, the roles of circadian genes in the development of CRC are still unexplored. In this study, we investigated the expression pattern and the underlying mechanism of human Clock gene (hClock) in CRC progression.
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