Krüppel associated box
Encyclopedia
The Krüppel associated box (KRAB) domain is a category of transcriptional
repression domains present in approximately 200 human zinc finger protein
-based transcription factor
s. The KRAB domain typically consists of about 75 amino acid residues whilst the minimal repression module is approximately 45 amino acid residues. It is predicted to function through protein-protein interactions via two amphipathic helices. Substitutions for the conserved residues abolish repression.
Over 10 independently encoded KRAB domains have been shown to be effective repressors of transcription, suggesting this activity to be a common property of the domain.
The KRAB containing C2H2-ZNF genes constitute the largest sub-family of zinc finger genes. More than half of the C2H2-ZNF genes are associated with a KRAB domain in the human genome. They are more prone to clustering and are found in large clusters on the human genome.
Examples of KRAB-ZFPs include ZNF43
, ZNF184
, ZNF91, HPF4, HTF10 and HTF34.
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
repression domains present in approximately 200 human zinc finger protein
Zinc finger protein
A zinc finger protein is a DNA-binding protein domain consisting of zinc fingers ranging from two in the Drosophila regulator ADR1, the more common three in mammalian Sp1 up to nine in TFIIIA...
-based transcription factor
Transcription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...
s. The KRAB domain typically consists of about 75 amino acid residues whilst the minimal repression module is approximately 45 amino acid residues. It is predicted to function through protein-protein interactions via two amphipathic helices. Substitutions for the conserved residues abolish repression.
Over 10 independently encoded KRAB domains have been shown to be effective repressors of transcription, suggesting this activity to be a common property of the domain.
Evolution of the KRAB domain
The KRAB domain has been found in association with the C2H2-Zinc finger proteins and is confined to mammalian genomes.The KRAB containing C2H2-ZNF genes constitute the largest sub-family of zinc finger genes. More than half of the C2H2-ZNF genes are associated with a KRAB domain in the human genome. They are more prone to clustering and are found in large clusters on the human genome.
Examples of KRAB-ZFPs include ZNF43
ZNF43
Zinc finger protein 43 is a protein that in humans is encoded by the ZNF43 gene....
, ZNF184
ZNF184
Zinc finger protein 184, also known as ZNF184, is a protein that in humans is encoded by the ZNF184 gene on chromosome 6. It was first identified by Goldwurm et al. in 1996....
, ZNF91, HPF4, HTF10 and HTF34.