Functional dissection of the HNF-1alpha transcription factor: a study on nuclear localization and transcriptional activation

DNA Cell Biol. 2005 Nov;24(11):661-9. doi: 10.1089/dna.2005.24.661.

Abstract

Hepatocyte nuclear factor-1alpha (HNF-1alpha) is a homeodomain-containing transcription factor regulating the expression of liver and pancreas-specific genes. Mutations in the HNF-1alpha-encoding gene TCF1 cause maturity-onset diabetes of the young, type 3 (MODY3). These mutations may affect nuclear import or reduce the ability of HNF-1alpha to stimulate transcription. We performed a functional dissection of HNF-1alpha, attempting both to define its nuclear localization signals (NLSs) and to identify important elements of the Cterminal transactivation domain. Three HNF-1alpha regions, A (amino acids 158-171), B (197-205), and C (271-282), highly similar to consensus NLSs, were studied by immunolocalization in HeLa cells. Region B could be identified as the most critical for correct nuclear localization. Deletion of two subregions (amino acids 398-470 and 544-631, respectively) in the HNF-1alpha C-terminal transactivation domain, resulted in the greatest reduction in stimulation of transcription compared to wild-type protein. However, this domain probably consists of many elements that work in concert to give the full transactivation potential of the protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Cell Compartmentation
  • Genes, Reporter
  • HeLa Cells
  • Hepatocyte Nuclear Factor 1-alpha / genetics
  • Hepatocyte Nuclear Factor 1-alpha / metabolism*
  • Humans
  • Luminescent Proteins / genetics
  • Molecular Sequence Data
  • Mutation
  • Nuclear Localization Signals / metabolism*
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Subcellular Fractions / metabolism
  • Transcriptional Activation*

Substances

  • Bacterial Proteins
  • Hepatocyte Nuclear Factor 1-alpha
  • Luminescent Proteins
  • Nuclear Localization Signals
  • Recombinant Fusion Proteins
  • yellow fluorescent protein, Bacteria