Abstract
The homeodomain (HD) protein Nkx6.1 is the most beta-cell-specific transcription factor known in the pancreas and its function is critical for the formation of the insulin-producing beta-cells. However, the target genes, DNA-binding site, and transcriptional properties of Nkx6.1 are unknown. Using in vitro binding site selection we have identified the DNA sequence of the Nkx6.1 binding site to be TTAATTG/A. A reporter plasmid containing four copies of this sequence is activated by an Nkx6.1HD/VP16 fusion construct. Full-length Nkx6.1 fails to activate this reporter plasmid in spite of robust interaction with the binding site in vitro. Stable expression of Nkx6.1 in the glucagon-producing alpha-cell-like MSL-G-AN cells induces expression of the endogenous insulin gene in a subset of the cell population. The expression of other known beta-cell-specific factors such as Pax4, Pax6, Pdx1, GLUT2 and GLP1-R is unchanged by the introduction of Nkx6.1.
| Original language | English |
|---|---|
| Journal | FEBS Letters |
| Volume | 461 |
| Issue number | 3 |
| Pages (from-to) | 287-94 |
| Number of pages | 8 |
| ISSN | 0014-5793 |
| Publication status | Published - 19 Nov 1999 |
| Externally published | Yes |
Keywords
- Amino Acid Sequence
- Animals
- Base Sequence
- Binding Sites
- Cloning, Molecular
- DNA
- DNA, Complementary
- DNA-Binding Proteins
- Genes, Reporter
- Glucagonoma
- Homeodomain Proteins
- Islets of Langerhans
- Molecular Sequence Data
- Pancreatic Neoplasms
- Protein Binding
- Rats
- Recombinant Fusion Proteins
- Sequence Alignment
- Sequence Homology, Amino Acid
- Transcriptional Activation
- Tumor Cells, Cultured