Additive effect of mPer1 and mPer2 antisense oligonucleotides on light-induced phase shift

Area of Science:

• Chronobiology
• Molecular Biology
• Neuroscience

Background:

• Light exposure is known to induce mPer1 and mPer2 mRNA in the suprachiasmatic nucleus.
• Previous research indicated that mPer1 antisense oligonucleotides (ODNs) inhibit light-induced phase delays in mouse locomotor rhythm.

Purpose of the Study:

• To determine if mPer1 and/or mPer2 gene expression is essential for light-induced circadian rhythm phase shifts.
• To investigate the specific roles of mPer1 and mPer2 in the photic entrainment process.

Main Methods:

• Utilizing antisense ODNs to inhibit the expression of mPer1, mPer2, and mPer3 mRNA in mice.
• Examining the impact of antisense ODN microinjections on light-induced phase delays in circadian behavior rhythms.
• Employing scrambled ODNs as controls to ensure specificity of the antisense effects.

Main Results:

• Microinjection of mPer1 or mPer2 antisense ODNs moderately attenuated light-induced phase delays.
• No significant effect on phase delays was observed with mPer3 antisense ODNs or scrambled ODNs.
• Simultaneous injection of both mPer1 and mPer2 antisense ODNs resulted in the complete disappearance of light-induced phase delays.

Conclusions:

• Both mPer1 and mPer2 gene induction are crucial for normal light-induced phase delays in mouse circadian rhythms.
• The expression of mPer1 and mPer2 genes appears to have an additive effect on the process of photic entrainment.
• These findings highlight the cooperative role of mPer1 and mPer2 in mediating the circadian system's response to light cues.