Fork head domain
Encyclopedia
The fork head domain is a type of protein domain
which is often found in transcription factor
s and whose purpose is to bind DNA
.
, a transcription factor that promotes terminal rather than segmental development, contains neither homeodomains nor zinc-fingers characteristic of other transcription factors. Instead, it contains a distinct type of DNA-binding region
, containing around 100 amino acids, which has since been identified in a number of transcription factors (including D. melanogaster FD1-5, mammalian HNF3, human HTLF, Saccharomyces cerevisiae
HCM1, etc.). This is referred to as the fork head domain but is also known as a "winged helix
". The fork head domain binds B-DNA as a monomer, but shows no similarity to previously identified DNA-binding motifs. Although the domain is found in several different transcription factors, a common function is their involvement in early developmental decisions of cell fates during embryogenesis
. Members of the class O of forkhead box transcription factors (FoxO) have important roles in metabolism, cellular proliferation, stress tolerance and probably lifespan.
Protein domain
A protein domain is a part of protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural...
which is often found in 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 and whose purpose is to bind DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
.
Function
The fork head protein of Drosophila melanogasterDrosophila melanogaster
Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...
, a transcription factor that promotes terminal rather than segmental development, contains neither homeodomains nor zinc-fingers characteristic of other transcription factors. Instead, it contains a distinct type of DNA-binding region
DNA-binding domain
A DNA-binding domain is an independently folded protein domain that contains at least one motif that recognizes double- or single-stranded DNA. A DBD can recognize a specific DNA sequence or have a general affinity to DNA...
, containing around 100 amino acids, which has since been identified in a number of transcription factors (including D. melanogaster FD1-5, mammalian HNF3, human HTLF, Saccharomyces cerevisiae
Saccharomyces cerevisiae
Saccharomyces cerevisiae is a species of yeast. It is perhaps the most useful yeast, having been instrumental to baking and brewing since ancient times. It is believed that it was originally isolated from the skin of grapes...
HCM1, etc.). This is referred to as the fork head domain but is also known as a "winged helix
Winged-helix transcription factors
Consisting of about 110 amino acids, the domain in winged-helix transcription factors has four helices and a two-strand beta-sheet.These proteins are classified into 17 families called FoxA-FoxQ....
". The fork head domain binds B-DNA as a monomer, but shows no similarity to previously identified DNA-binding motifs. Although the domain is found in several different transcription factors, a common function is their involvement in early developmental decisions of cell fates during embryogenesis
Embryogenesis
Embryogenesis is the process by which the embryo is formed and develops, until it develops into a fetus.Embryogenesis starts with the fertilization of the ovum by sperm. The fertilized ovum is referred to as a zygote...
. Members of the class O of forkhead box transcription factors (FoxO) have important roles in metabolism, cellular proliferation, stress tolerance and probably lifespan.