Per1 mutation enhances masking responses in mice

ABSTRACT

Light can restrict the activity of an animal to a diurnal or nocturnal niche by synchronizing its endogenous clock (entrainment) which controls the sleep wake cycle. Light can also directly change an animal’s activity level (masking). In mice, high illumination levels decrease activity, i.e. negative masking occurs. To investigate the role of core circadian clock genes Per1 and Per2 in masking, we used a 5-day behavioral masking protocol consisting of 3 h pulses of light given in the night at various illuminances (4–5 lux, 20 lux and 200 lux). Mice lacking the Per1 gene had decreased locomotion in the presence of a light pulse compared to wild-type, Per2 and Per1 Per2 double mutant mice. Per2 single mutant and Per1 Per2 double mutant mice did not show significantly different masking responses compared to wild-type controls. This suggests that Per1 suppresses negative masking responses in mice.

KEYWORDS:

• Negative masking
• behavior
• per genes
• circadian clock
• locomotor activity

Acknowledgements

This study was supported by the NeuroTime Erasmus+ grant (European Union) and the Centre National pour la Recherche Scientifique. NM is supported by the Oskar Öflunds Foundation (Finland), Ella and Georg Ehrnrooth Foundation (Finland) and the Academy of Finland (decision number: 340127). We extend our gratitude to Cristina Sandu, INCI. We thank Dr D. Sage, Dr S. Reibel and N. Lethenet from the Chronobiotron (UMS 3415) for animal care and Dr U. Albrecht (University of Freiburg) for the Per1^−/− Per2^Brdm1 mice.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Raw data that support the findings of this study are available from the corresponding authors, upon reasonable request.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/07420528.2022.2126321

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This research was supported by the Oskar Öflunds Foundation, Ella and Georg Ehrnrooth Foundation, the Academy of Finland [decision number: 340127], NeuroTime Erasmus+ of the European Commission and the Centre National pour la Recherche Scientifique, France.