Long-term in vivo recording of circadian rhythms in brains of freely moving mice

Proc Natl Acad Sci U S A. 2018 Apr 17;115(16):4276-4281. doi: 10.1073/pnas.1717735115. Epub 2018 Apr 2.

Abstract

Endogenous circadian clocks control 24-h physiological and behavioral rhythms in mammals. Here, we report a real-time in vivo fluorescence recording system that enables long-term monitoring of circadian rhythms in the brains of freely moving mice. With a designed reporter of circadian clock gene expression, we tracked robust Cry1 transcription reporter rhythms in the suprachiasmatic nucleus (SCN) of WT, Cry1-/- , and Cry2-/- mice in LD (12 h light, 12 h dark) and DD (constant darkness) conditions and verified that signals remained stable for over 6 mo. Further, we recorded Cry1 transcriptional rhythms in the subparaventricular zone (SPZ) and hippocampal CA1/2 regions of WT mice housed under LD and DD conditions. By using a Cre-loxP system, we recorded Per2 and Cry1 transcription rhythms specifically in vasoactive intestinal peptide (VIP) neurons of the SCN. Finally, we demonstrated the dynamics of Per2 and Cry1 transcriptional rhythms in SCN VIP neurons following an 8-h phase advance in the light/dark cycle.

Keywords: circadian clock; in vivo fluorescence recording; light/dark cycle; phase advance; suprachiasmatic nucleus.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bacterial Proteins / analysis
  • Bacterial Proteins / genetics
  • CA1 Region, Hippocampal / metabolism
  • CA2 Region, Hippocampal / metabolism
  • Cells, Cultured
  • Circadian Rhythm / genetics
  • Circadian Rhythm / physiology*
  • Cryptochromes / biosynthesis*
  • Cryptochromes / deficiency
  • Cryptochromes / genetics
  • Dependovirus / genetics
  • Fiber Optic Technology / instrumentation
  • Fiber Optic Technology / methods*
  • Fluorometry / instrumentation
  • Fluorometry / methods*
  • Genes, Reporter
  • Genetic Vectors / administration & dosage
  • Genetic Vectors / genetics
  • Hypothalamus, Anterior / metabolism
  • Longitudinal Studies
  • Luminescent Proteins / analysis
  • Luminescent Proteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Movement
  • Neurons / chemistry
  • Neurons / classification
  • Neurons / metabolism*
  • Optical Fibers
  • Organ Specificity
  • Period Circadian Proteins / biosynthesis*
  • Period Circadian Proteins / genetics
  • Photoperiod
  • Suprachiasmatic Nucleus / cytology
  • Suprachiasmatic Nucleus / metabolism*
  • Transcription, Genetic
  • Vasoactive Intestinal Peptide / analysis

Substances

  • Bacterial Proteins
  • Cry1 protein, mouse
  • Cry2 protein, mouse
  • Cryptochromes
  • Luminescent Proteins
  • Per2 protein, mouse
  • Period Circadian Proteins
  • yellow fluorescent protein, Bacteria
  • Vasoactive Intestinal Peptide