POU domain
| Pou domain - N-terminal to homeobox domain | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | Pou | ||||||||
SCOP2 | 1oct / SCOPe / SUPFAM | ||||||||
| |||||||||
POU (pronounced 'pow') is a
homeodomains.[1] The Pou domain is a bipartite DNA binding domain
found in these proteins.
Etymology
The acronym POU is derived from the names of three transcription factors:
- the Pituitary-specific Pit-1
- the Octamer transcription factor proteins Oct-1 and Oct-2 (octamer sequence is ATGCAAAT)
- the neural Unc-86 transcription factor from Caenorhabditis elegans.
Diversity
POU domain
genes
have been described in organisms as divergent as
Caenorhabditis elegans, Drosophila, Xenopus,
plants
and fungi
.
Comparisons of POU domain genes across the animals suggests that the family can be divided into six major classes (POU1-POU6).
POU4. The six classes diverged early in animal evolution: POU1, POU3, POU4, and POU6 classes evolved before the last common ancestor of sponges and eumetazoans, POU2 evolved in the Bilatera, and POU5 appears to be unique to vertebrates.[2]
There is a surprisingly high degree of amino acid sequence conservation (37%-42%) of POU homeodomains to the transcriptional regulator comS, the competence protein from the
Akin to the way that POU homeodomain regulators lead to tissue differentiation inmetazoans
, this
transcription factor is critical for differentiation of a subpopulation
of B. subtilis into a state of genetic competence
.
Function
POU proteins are eukaryotic
DNA binding domain referred to as the POU domain. The various members of the POU family have a wide variety of functions, all of which are related to the function of the neuroendocrine system[4] and the development of an organism.[5] Some other genes are also regulated, including those for immunoglobulin light and heavy chains (Oct-2),[6][7] and trophic hormone
genes, such as
those for prolactin and growth hormone (Pit-1).
Structure
The POU domain is a bipartite domain composed of two subunits separated by a non-conserved region of 15-55 aa. The
flexible linker.[9][10][11] In proteins a POU-specific domain is always accompanied by a homeodomain. Despite the lack of sequence homology, 3D structure of POUs is similar to 3D structure of bacteriophage lambda repressor and other members of HTH_3 family.[9][10]
Examples
Human genes encoding proteins containing the POU domain and related pseudogenes include:
- HDX;
- POU1F1;
- POU2F1; POU2F2; POU2F3;
- POU3F3; POU3F4;
- POU4F1; POU4F2; POU4F3;
- ;
- POU5F2;
- POU6F1; POU6F2