T-box
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T-box refers to a group of transcription factors involved in embryonic limb and heart development.[1] Every T-box protein has a relatively large DNA-binding domain, generally comprising about a third of the entire protein that is both necessary and sufficient for sequence-specific DNA binding. All members of the T-box gene family bind to the "T-box", a DNA consensus sequence of TCACACCT.[2]
Members
T-boxes are especially important to the development of embryos, found in
Mutations in the first one found caused short tails in mice, and thus the protein encoded was named
The mouse Tbxt gene was cloned[7] and found to be a 436 amino acid embryonic nuclear transcription factor. The protein brachyury binds to the T-box through a region at its N-terminus.
Protein activity
The encoded proteins of
Defects
In humans, and some other animals, defects in the TBX5 gene expression are responsible for Holt–Oram syndrome, which is characterized by at least one abnormal wrist bone. Other arm bones are almost always affected, though the severity can vary widely, from complete absence of a bone, to only a reduction in bone length.[11][12] Seventy-five percent of affected individuals also have heart defects, most often there is no separation between the left and right ventricle of the heart.[13]
TBX3 is associated with ulnar–mammary syndrome in humans, but is also responsible for the presence or absence of dun color in horses, and has no deleterious effects whether expressed or not.[14]
T-box genes
Genes encoding T-box proteins include:
See also
References
- PMID 12093383.
- S2CID 13138577.
- PMID 16285859.
- ^ "Entrez Gene: T".
- PMID 8963900.
- S2CID 25311702.
- S2CID 4365020.
- ^ PMID 26249743.
- S2CID 4330287.
- PMID 20152185.
- ^ "Holt–Oram syndrome". Genetics Home Reference. U.S. National Library of Medicine. June 2014. Retrieved 18 April 2018.
- ^ McDermott DA, Fong JC, Basson CT. Holt–Oram Syndrome. 2004 Jul 20 [Updated 2015 Oct 8]. In Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2018. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1111/
- S2CID 19665997.
- PMID 26691985.
- "A horse of a different color: Genetics of camouflage and the dun pattern". ScienceDaily (Press release). December 21, 2015.
Further reading
- Meisler MH (1997). "Mutation watch: mouse brachyury (T), the T-box gene family, and human disease". Mammalian Genome. 8 (11): 799–800. S2CID 12617264.
External links
- T-Box+Domain+Proteins at the U.S. National Library of Medicine Medical Subject Headings (MeSH)