Molecular cloning of cDNA encoding a human TFEC isoform, a newly identified transcriptional regulator

Ken Ichi Yasumoto, Shigeki Shibahara

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


TFEC is a transcriptional repressor originally identified in rat chondrosarcoma and contains a basic helix-loop-helix and leucine zipper (bHLH/LZ) structure. TFEC shares a closely related bHLH/LZ structure with microphthalmia-associated transcription factor (MITF) and TFE3. In the course of cDNA cloning for a factor structurally related to MITF which is also a regulator for cell differentiation, we have isolated cDNA clones from a THP- 1 human monocytic leukemia cell line. These cDNAs encode a protein of 347 amino acids, termed TFECL, a human homolog of a putative rat TFEC isoform. TFECL contains an acidic domain that corresponds to a transcriptional activation domain of TFE3 but its equivalent region is deleted in rat TFEC. We explored a function of TFECL using a melanocyte-specific tyrosinase gene and a ubiquitously expressed heme oxygenase-1 gene, each promoter containing the cis-acting CANNTG motifs. By transient coexpression assays, we showed that TFECL is able to activate or inhibit transcription of a reporter gene linked to either the tyrosinase or the heme oxygenase-1 gene promoter, depending on cell types. These results suggest that TFECL may function as a transcriptional activator under certain conditions.

Original languageEnglish
Pages (from-to)23-31
Number of pages9
JournalBiochimica et Biophysica Acta - Gene Structure and Expression
Issue number1
Publication statusPublished - 1997 Jul 17


  • cDNA
  • Cloning
  • Transcriptional regulator


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