Circadian oscillation of 64-kDa polypeptide in the rat suprachiasmatic nucleus.
In cell suspensions of suprachiasmatic nucleus harvested every 3 hr from rats kept under 12 hr: 12 hr light-dark cycle and constant darkness, we have detected a M(r) 64-kDa protein whose synthesis exhibits two distinct daily peaks in SDS-PAGE. Analysis of densitometer tracings revealed that the synthesis of other proteins was independent of the time of day or not reproducible. Maximum synthesis of the 64-kDa polypeptide occurred at around CT6 and CT21, which are almost coincident with the phase advance regions of circadian activity rhythm induced by anisomycin and light pulses [15], respectively. These results suggest that the 64-kDa protein in SDS-PAGE may be a part of the circadian clock mechanism.
Nishi
R
R
Department of Veterinary Physiology, Faculty of Agriculture, Miyazaki University, Japan.
Murakami
N
N
Marumoto
N
N
Nasu
T
T
Kuroda
H
H
Etoh
T
T
D000818:Animals; D002478:Cells, Cultured; D002940:Circadian Rhythm; D003624:Darkness; D066298:In Vitro Techniques; D008027:Light; D008297:Male; D008715:Methionine / Q000378:metabolism; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013493:Suprachiasmatic Nucleus / Q000378:metabolism* / Q000502:physiology
D009419:Nerve Tissue Proteins; D008715:Methionine