Anti-PER2 (aa 1-100) polyclonal antibody

In recent years, it has become increasingly apparent that antisense transcription plays an important role in the regulation of gene expression. The circadian clock is no exception: an antisense transcript of the mammalian core-clock gene PERIOD2 (PER2), which we shall refer to as Per2AS RNA, oscillates with a circadian period and a nearly 12 h phase shift from the peak expression of Per2 mRNA. In this paper, we ask whether Per2AS plays a regulatory role in the mammalian circadian clock by studying in silico the potential effects of interactions between Per2 and Per2AS RNAs on circadian rhythms. Based on the antiphasic expression pattern, we consider two hypotheses about how Per2 and Per2AS mutually interfere with each other's expression. In our pre-transcriptional model, the transcription of Per2AS RNA from the non-coding strand represses the transcription of Per2 mRNA from the coding strand and vice versa. In our post-transcriptional model, Per2 and Per2AS transcripts form a double-stranded RNA duplex, which is rapidly degraded. To study these two possible mechanisms, we have added terms describing our alternative hypotheses to a published mathematical model of the molecular regulatory network of the mammalian circadian clock. Our pre-transcriptional model predicts that transcriptional interference between Per2 and Per2AS can generate alternative modes of circadian oscillations, which we characterize in terms of the amplitude and phase of oscillation of core clock genes. In our post-transcriptional model, Per2/Per2AS duplex formation dampens the circadian rhythm. In a model that combines pre- and post-transcriptional controls, the period, amplitude and phase of circadian proteins exhibit non-monotonic dependencies on the rate of expression of Per2AS. All three models provide potential explanations of the observed antiphasic, circadian oscillations of Per2 and Per2AS RNAs. They make discordant predictions that can be tested experimentally in order to distinguish among these alternative hypotheses.

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. The present study demonstrated that the protein expression levels of human circadian locomoter output cycles protein kaput (hCLOCK) is significantly increased, while miR-124 is attenuated in high-grade human CRC tissues and in the more invasive colorectal cancer cell lines SW620 and LOVO. It was further demonstrated that hCLOCK is a direct target of miR-124. Upregulation of miR-124 significantly inhibited hCLOCK expression in LOVO cells, and consequently inhibited its promoting effects on the proliferation and migration of LOVO cells. In conclusion, these data revealed that hCLOCK serves an enhancing role, whereas mir-124 serves a suppressive role, in human CRC. Attenuation of miR-124, of which hCLOCK is a direct target, leads to increased hCLOCK expression and disruption of circadian rhythms in CRC.