A Negative Regulatory Element Required for Light-Dependent pinopsin Gene Expression

Yoko Takanaka, Toshiyuki Okano, Kazuyuki Yamamoto, Yoshitaka Fukada

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

In vertebrates, a variety of light-stimulated genes are distributed in the retina, the pineal gland, and the suprachiasmatic nucleus, but a cis-element(s) responsible for the light-dependent transcriptional regulation is left unexplored. Focusing on the pinopsin gene, a light-stimulated gene in the chick pineal gland, we performed a transcriptional analysis in the primary culture of the chick pineal cells that were transiently transfected with a luciferase reporter gene fused with various lengths of the 5′ upstream region of the pinopsin gene. Light-dependent enhancer activity was detectable in the construct with the upstream region between -1156 and +31. Introduction of mutations within the 18 bp sequence at positions -1103 to -1086 (TGGCACGTGGGGTTCCTC), including a CACGTG E-box sequence, elevated the transcriptional activity in the dark and thereby abrogated the light dependency, suggesting that the 18 bp sequence is essential for a reduction of the transcriptional activity in the dark. In an electrophoretic mobility-shift assay, we identified a pineal nuclear factor(s) capable of binding to the 18 bp element in a sequence-specific manner. When a 49 bp fragment (-1122 to -1074) including the 18 bp sequence was placed upstream of the simian virus 40 promoter, the transcriptional activity was dramatically suppressed regardless of light conditions in the chick pineal cells, and a more pronounced repression was observed in nonpineal/nonphotosensory LMH and NIH 3T3 cells. These results suggest that the 18 bp element in the pinopsin promoter constitutes the binding site of a ubiquitous factor that serves for the transcriptional repression that is required, although not sufficient, for the light-dependent expression of pinopsin gene in the chick pinealocytes.

Original languageEnglish
Pages (from-to)4357-4363
Number of pages7
JournalJournal of Neuroscience
Volume22
Issue number11
Publication statusPublished - 2002 Jun 1

Keywords

  • Chicken
  • Gene expression
  • Light induction
  • Pineal gland
  • Transcriptional regulation
  • pinopsin gene

ASJC Scopus subject areas

  • Neuroscience(all)

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