Molecule of the Month: Oct and Sox Transcription Factors
Transcription factors decide when particular genes will be transcribed
Choosing a Path
Exploring the Structure
Oct and Sox Transcription Factors (PDB entries 1gt0 and 1o4x)
Combinatorial control, where several transcription factors bind together to control a gene, allows the same proteins to be used in different ways. This is shown in two structures of Oct1 and Sox2 bound to different pieces of regulatory DNA. In PDB entry 1gt0 (left), the proteins are bound to the FGF4 enhancer DNA and the two proteins interact weakly through and extended tail of Sox2. In PDB entry 1o4x (right), the proteins are bound closer together on the Hoxb1regulatory sequence and they form a stronger interaction. In this way, the different spacing of the binding sites in the DNA can control the binding strength of the Oct and Sox complex. To explore these structures in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- Researchers have used a variety of other transcription factors along with Oct4 and Sox2 for reprogramming cells, including Nanog and Lin-28. The DNA-binding portions of these proteins are available in the PDB. Can you find similarities and differences with the transcription factors shown here?
- Many DNA-binding proteins bend DNA when they bind. Can you find other examples in the PDB?
April 2009, David Goodselldoi:10.2210/rcsb_pdb/mom_2009_4