mPer2 antisense oligonucleotides inhibit mPER2 expression but not circadian rhythms of physiological activity in cultured suprachiasmatic nucleus neurons.
Various day-night rhythms, observed at molecular, cellular, and behavioral levels, are governed by an endogenous circadian clock, predominantly functioning in the hypothalamic suprachiasmatic nucleus (SCN). A class of clock genes, mammalian Period (mPer), is known to be rhythmically expressed in SCN neurons, but the correlation between mPER protein levels and autonomous rhythmic activity in SCN neurons is not well understood. Therefore, we blocked mPer translation using antisense phosphothioate oligonucleotides (ODNs) for mPer1 and mPer2 mRNAs and examined the effects on the circadian rhythm of cytosolic Ca2+ concentration and action potentials in SCN slice cultures. Treatment with mPer2 ODNs (20microM for 3 days) but not randomized control ODNs significantly reduced mPER2 immunoreactivity (-63%) in the SCN. Nevertheless, mPer1/2 ODNs treatment inhibited neither action potential firing rhythms nor cytosolic Ca2+ rhythms. These suggest that circadian rhythms in mPER protein levels are not necessarily coupled to autonomous rhythmic activity in SCN neurons.
Sugiyama
Takashi
T
Advanced Research Institute for Bioscience, Waseda University, 2-7-5 Higashifushimi, Nishi-Tokyo, Tokyo 202-0021, Japan.
Yoshioka
Tohru
T
Ikeda
Masayuki
M
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D020868:Gene Silencing / Q000502:physiology; D018014:Gene Transfer Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000502:physiology*; D009687:Nuclear Proteins / Q000502:physiology*; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000235:genetics*; D056950:Period Circadian Proteins; D014176:Protein Biosynthesis / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000502:physiology*; D013873:Thionucleotides / Q000008:administration & dosage / Q000235:genetics; D014018:Tissue Distribution; D014157:Transcription Factors
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D016376:Oligonucleotides, Antisense; C539023:Per1 protein, mouse; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins; D013873:Thionucleotides; D014157:Transcription Factors