Hox regulation of transcription: more complex(es)
Department of Biochemistry and Molecular Pharmacology
Medical Subject Headings
Animals; Drosophila Proteins; Genes, Homeobox; Homeodomain Proteins; Humans; Transcription Factors; Transcription, Genetic
Biochemistry | Cell Biology | Developmental Biology | Molecular Biology | Molecular Genetics
Hox genes encode transcription factors with important roles during embryogenesis and tissue differentiation. Genetic analyses initially demonstrated that interfering with Hox genes has profound effects on the specification of cell identity, suggesting that Hox proteins regulate very specific sets of target genes. However, subsequent biochemical analyses revealed that Hox proteins bind DNA with relatively low affinity and specificity. Furthermore, it became clear that a given Hox protein could activate or repress transcription, depending on the context. A resolution to these paradoxes presented itself with the discovery that Hox proteins do not function in isolation, but interact with other factors in complexes. The first such "cofactors" were members of the Extradenticle/Pbx and Homothorax/Meis/Prep families. However, the list of Hox-interacting proteins has continued to grow, suggesting that Hox complexes contain many more components than initially thought. Additionally, the activities of the various components and the exact mechanisms whereby they modulate the activity of the complex remain puzzling. Here, we review the various proteins known to participate in Hox complexes and discuss their likely functions. We also consider that Hox complexes of different compositions may have different activities and discuss mechanisms whereby Hox complexes may be switched between active and inactive states.
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Citation: Dev Dyn. 2014 Jan;243(1):4-15. doi: 10.1002/dvdy.23997. Epub 2013 Jul 22. Link to article on publisher's site
Ladam, Franck and Sagerstrom, Charles G., "Hox regulation of transcription: more complex(es)" (2014). University of Massachusetts Medical School Faculty Publications. 452.