Circadian and developmental regulation of Oct-2 gene expression in the suprachiasmatic nuclei.
Oct-2 is a transcriptional activating factor that is expressed in the suprachiasmatic nuclei (SCN), the site of a biological clock. We examined in rats whether Oct-2 gene expression is regulated by the circadian pacemaker or by light using quantitative in situ hybridization. The ontogeny of Oct-2 gene expression in the SCN was also studied. Oct-2 mRNA levels remained constant throughout the circadian cycle. In contrast to c-fos mRNA levels which are acutely induced by acute light exposure at night, Oct-2 mRNA levels were not increased by light exposure at night. At gestational day 18, the first age the SCN are anatomically distinct, a prominent Oct-2 hybridization signal was present in the SCN. Our results suggest that Oct-2 is constitutively expressed in the SCN and is present from the time the SCN are discernible as discrete nuclei in fetal brain.
Rivkees
S A
SA
Laboratory of Developmental Chronobiology, Children's Service, Massachusetts General Hospital, Boston 02114.
Weaver
D R
DR
Reppert
S M
SM
D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics* / Q000528:radiation effects; D005314:Embryonic and Fetal Development / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology* / Q000528:radiation effects; D017403:In Situ Hybridization; D008027:Light; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013493:Suprachiasmatic Nucleus / Q000196:embryology / Q000254:growth & development / Q000502:physiology*
D012333:RNA, Messenger