The Journal of Neuroscience, November 15, 1999, 19(22):10176-10183
A Putative Transcription Factor with Seven Zinc-Finger Motifs
Identified in the Developing Suprachiasmatic Nucleus by the
Differential Display PCR Method
Yoshiro
Maebayashi1, 2,
Yasufumi
Shigeyoshi1,
Toru
Takumi1, and
Hitoshi
Okamura1
1 Department of Anatomy and Brain Science, Kobe
University School of Medicine, Kobe 650-0017, Japan, and
2 Department of Psychiatry, Kyoto Prefectural University of
Medicine, Kyoto 602-8566, Japan
The suprachiasmatic nucleus (SCN) is a mammalian central circadian
pacemaker. This nucleus develops in the last stage of fetal life and
matures to make strong synaptic connections within 2 weeks of postnatal
life to establish strong oscillation characteristics. To identify
factors that initiate the circadian oscillation, we applied a
differential display PCR method to developing SCN, and isolated a gene
with seven zinc-finger motifs, Lot1, which encodes a
gene that appeared at a very high level in the SCN during the early
postnatal days. Lot1 mRNA first appeared at postnatal
day 1 (P1) at a very high level, and the signal in the SCN continued to
be very high until P10 and thereafter rapidly decreased until P20 and
was expressed at a very faint level during adulthood. Lot1 mRNA expression was observed only in neurons of the
dorsomedial SCN throughout the course of development. During the
developmental stage, Lot1 mRNA expression shows a
circadian rhythm with a peak in the day time and a trough at night time
in both light-dark and constant dark conditions. These observations
imply that Lot1 is the first identified putative
transcription factor expressed only in the period of active
synaptogenesis in the SCN, where Lot1 might play a role
in establishing autonomous oscillation.
Key words:
suprachiasmatic nucleus; Lot1; development; mRNA differential display; zinc finger; in situ
hybridization
Copyright © 1999 Society for Neuroscience 0270-6474/99/192210176-08$05.00/0