Circadian Oscillation of Natural Antisense Transcripts Related to Human Core Clock Genes

Circadian clocks are autonomous intracellular oscillators that synchronize metabolic and physiological processes with the external signals. So, misalignment of environmental and endogenous circadian rhythms leads to disruption of biological activities in living organisms. Noncoding transcripts
including antisense RNAs are an important component of the molecular clocks. Commonly, the antisense transcripts are involved in the regulation of gene expression. PER2AS and CRY1AS are the only known Natural Antisense Transcripts (NAT) among the core clock genes, which overlap with the PER2 and CRY1 genes, respectively. In this study, we hypothesized that PER2AS and CRY1AS like the other clock genes, exhibit the oscillatory behavior in a 24-hour period and affect the expression of PER2 and CRY1.

First, the A549 cell line was cultured under standard conditions. After horse serum shock, RNA extraction and cDNA synthesis was performed; then the expression fluctuations of PER2AS, CRY1AS, PER2, and CRY1 were measured with Real-time PCR. 

Our result showed that PER2AS and CRY1AS had similar oscillation patterns with their sense strand during 24-hour period.

Therefore, we suggested that PER2AS and CRY1AS transcripts probably by preventing the interaction of miRNAs with PER2 and CRY1 mRNAs, influence the expression of them, positively.