Hox protein: Difference between revisions
Eric Martz (talk | contribs) No edit summary |
Eric Martz (talk | contribs) |
||
| Line 11: | Line 11: | ||
Hox proteins are transcription factors that play a key role in the '''embryonic development''' across species by activating and repressing genes. In ''Drosophila,'' eight Hox proteins are responsible for the development of different body segments of the fly, such as its antennae, wings, or legs. Hox proteins execute their distinct functions through binding to similar but different in vivo binding sites<ref>Mann RS, Lelli KM, Joshi R. Hox specificity unique roles for cofactors and collaborators. Curr Top Dev Biol. 2009;88:63-101. [http://www.ncbi.nlm.nih.gov/pubmed/19651302 PMID:19651302]</ref>. This page discusses molecular mechanisms through which Hox proteins recognize their DNA targets with very high binding specificity. <br/> | Hox proteins are transcription factors that play a key role in the '''embryonic development''' across species by activating and repressing genes. In ''Drosophila,'' eight Hox proteins are responsible for the development of different body segments of the fly, such as its antennae, wings, or legs. Hox proteins execute their distinct functions through binding to similar but different in vivo binding sites<ref>Mann RS, Lelli KM, Joshi R. Hox specificity unique roles for cofactors and collaborators. Curr Top Dev Biol. 2009;88:63-101. [http://www.ncbi.nlm.nih.gov/pubmed/19651302 PMID:19651302]</ref>. This page discusses molecular mechanisms through which Hox proteins recognize their DNA targets with very high binding specificity. <br/> | ||
The crystal structure of a Hox-DNA complex (Figure 1) shows that the Hox protein Sex combs reduced (Scr) | The crystal structure of a Hox-DNA complex (Figure 1) shows that the Hox protein ''Sex combs reduced'' (Scr) binds its specific ''in vivo'' site with the help of cofactors, ''Extradenticle (Exd)/Pbx proteins''. Hox proteins can bind DNA as monomers but their binding specificity is enhanced when the co-factor is present, a principle that is called '''latent specificity''' (Figure 2). In ''Drosophila'', for instance, eight Hox proteins bind as heterodimers with their cofactor Exd to similar but distinct target sites.<br/> | ||
Hox proteins are expressed along the anterior-posterior axis of an embryo, thus determining the localization for the development of different body segments (Figure 2). This spatial order of expression from anterior to posterior is congruent with the location of the respective Hox genes at the chromosome, a fact known as '''collinearity'''. <br/> | Hox proteins are expressed along the anterior-posterior axis of an embryo, thus determining the localization for the development of different body segments (Figure 2). This spatial order of expression from anterior to posterior is congruent with the location of the respective Hox genes at the chromosome, a fact known as '''collinearity'''. <br/> | ||