Winged-helix transcription factors
Family of proteins
From Wikipedia, the free encyclopedia
A winged-helix transcription factor is a type of transcription factor that binds to DNA using a protein domain called a winged-helix domain. In some cases, the term has been used to refer specifically to the family of FOX proteins, where the winged-helix domain is used synonymously with fork head domain.[1] However, there are other families such as the RFX1-like transcription factors which have a similarly structured DNA-binding domain, despite having a very different mechanism of DNA-binding. These related transcription factors are also sometimes referred to as being winged-helix transcription factors.[2]
Winged-helix and Related Families
The FOX proteins and 2 other families (E2F and RFX) are sometimes grouped into a common “Forked head / winged helix factor” class of transcription factors.[3]
Forkhead Box Proteins
Consisting of about 110 amino acids, the domain in FOX proteins (see Regulation of gene expression) has four helices and two large loops which are the “wings”.[1] There are 50 human proteins in this family, and they are classified into 19 families called FoxA-FoxS.[4]
E2F Transcription Factors
The E2F family of transcription factors possesses a DNA-binding domain that is similar to a winged-helix.[5]
RFX Proteins
RFX (Regulatory Factor X) proteins is a small family of transcription factors with diverse roles. The 8 human proteins are called RFX1-8, and have a shared characteristic of binding to a particular sequence motif called the X-box. With the exception of RFX8, they each possess a similar conserved DNA-binding domain structured like a winged helix.[6]
