R. Nishi et al., CIRCADIAN OSCILLATION OF 64-KDA POLYPEPTIDE IN THE RAT SUPRACHIASMATIC NUCLEUS, Journal of veterinary medical science, 56(1), 1994, pp. 161-163
In cell suspensions of suprachiasmatic nucleus harvested every 3 hr fr
om rats kept under 12 hr: 12 hr light-dark cycle and constant darkness
, we have detected a Mr 64-kDa protein whose synthesis exhibits two di
stinct daily peaks in SDS-PAGE. Analysis of densitometer tracings reve
aled that the synthesis of other proteins was independent of the time
of day or not reproducible. Maximum synthesis of the 64-kDa polypeptid
e occurred at around CT6 and CT21, which are almost coincident with th
e phase advance regions of circadian activity rhythm induced by anisom
ycin and light pulses [15], respectively. These results suggest that t
he 64-kDa protein in SDS-PAGE may be a part of the circadian clock mec
hanism.