Octamer binding factor 1 (Oct-1)
- Ig-κ promoter
Transcription factor, which binds an octamer motif (5’-ATTTGCAT-3’) and activates the promoters of the genes for some small
nuclear RNAs (snRNA) and of genes such as those for histone H2B and immunoglobulins.
Domain organization/sequence features
POU domain transcription factors have two DNA- binding subdomains, connected by a linker, which is 23 residues in case of
Oct-1. The optimal binding site of POU domains differs between the family members, suggesting a contribution of the linker to
The linker is invisible in the crystal structure of the complex.
Varying the linker length and composition shows that the minimal linker length is 10-14 amino acids and a conserved Glu also
POU subdomains are expressed in different cell types. Linker flexibility affects specific activation of target genes. The coding
sequence for the two subdomains, POUs and POUhd, are separated by an intron in the genome. This could be a potential
determinant of linker length if differential splicing of the intron occurs. The Oct-1 linker intron is out-of-frame with the coding
sequence thus only alternative splicing of this intron could generate a different functional protein.
The length and composition of the fuzzy linker determines transcriptional activity of Oct-1 via transient, specific interactions.