Molecular Cloning of cDNA Encoding a Human TFEC Isoform, a Newly Identified Transcriptional Regulator

Biochim Biophys Acta. 1997 Jul 17;1353(1):23-31. doi: 10.1016/s0167-4781(97)00034-1.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Cloning, Molecular
  • DNA, Complementary / genetics*
  • DNA-Binding Proteins / genetics*
  • Humans
  • Microphthalmia-Associated Transcription Factor
  • Molecular Sequence Data
  • Transcription Factors / genetics*
  • Transcription, Genetic
  • Tumor Cells, Cultured


  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • DNA, Complementary
  • DNA-Binding Proteins
  • MITF protein, human
  • Microphthalmia-Associated Transcription Factor
  • TFE3 protein, human
  • TFEC protein, human
  • Transcription Factors

Associated data

  • GENBANK/D43945