Clock gene mRNA and protein rhythms in the pineal gland of mice.
In vertebrates, the rhythmic transcription of clock genes, regulated by their own gene products, provides the basis for self-sustaining circadian clockworks. These endogenous clocks are lost in most mammalian tissues, but not in the central pacemaker of the hypothalamic suprachiasmatic nucleus (SCN). An interesting model system to understand this phylogenetic shift in function of clock gene products is the rodent pineal gland, as its intrinsic clockwork was replaced during evolution by an input-dependent oscillator. By means of immunohistochemistry, immunoblotting and real time PCR, we investigated the day/night expression profiles of all major clock genes and their products in the pineal gland of one melatonin-proficient and one melatonin-deficient mouse strain. All clockwork elements known to be indispensable for a sustained rhythm generation in the SCN were also found in the pineal organ of both mouse strains. Only mPer1 mRNA and PER1 protein accumulation coincides with timecourses of many other pineal genes and their products, which are cyclicAMP inducible. Here, presented data together with the known mechanisms for regulation of the mPer1 gene in the rodent pineal gland forward the idea that in this tissue PER1 may have a trigger function for initiating the cycles of the clockwork's transcriptional/translational feedback loops.
Karolczak
Magdalena
M
Dr Senckenbergische Anatomie, Institute of Anatomy II, Johann Wolfgang Goethe-University Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt, Germany.
Burbach
Guido J
GJ
Sties
Gabriele
G
Korf
Horst-Werner
HW
Stehle
Jörg H
JH
D000818:Animals; D001683:Biological Clocks / Q000235:genetics*; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D005786:Gene Expression Regulation; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D008550:Melatonin / Q000172:deficiency; D051379:Mice; D009687:Nuclear Proteins / Q000096:biosynthesis*; D056950:Period Circadian Proteins; D010870:Pineal Gland / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013493:Suprachiasmatic Nucleus / Q000502:physiology; D015534:Trans-Activators / Q000096:biosynthesis* / Q000235:genetics*
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C539023:Per1 protein, mouse; D056950:Period Circadian Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D056926:CLOCK Proteins; C538944:Clock protein, mouse; D008550:Melatonin