Mode of activation of the GC box/Spl-dependent promoter of the human NADH-cytochrome b5 reductase-encoding gene

Atsushi Toyoda, Yasuyuki Fukumaki, Masahira Hattori, Yoshiyuki Sakaki

Research output: Contribution to journalArticle

14 Citations (Scopus)


Many eukaryote promoters, particularly those for so-called housekeeping genes, have multiple GC boxes which are the binding sites of the transcription factor, Spl. It has been proposed that Spl binds to the multiple GC boxes, and then the GC box-bound Spl interact with each other to synergistically stimulate transcription. Here, we describe a Spl-dependent promoter which does not necessarily fit the synergistic activation mechanism. The promoter of the human NADH-cytochrome b5 reductase-encoding gene (CYTB5R) possesses five potential GC box sequences. Deletion and mutagenesis studies coupled with CAT assays revealed that three out of five GC box-like sequences were functionally active and activated transcription additively (rather than synergistically). Our results suggested that Spl-mediated activation of transcription occurs in a promoter context-dependent manner.

Original languageEnglish
Pages (from-to)351-355
Number of pages5
Issue number2
Publication statusPublished - 1995 Oct 27
Externally publishedYes



  • additive activation
  • b5R
  • CAT assay
  • DNaseI footprinting
  • Housekeeping gene

ASJC Scopus subject areas

  • Genetics

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