Homeobox sequence

The homeobox sequence found in three Drosophila regulatory proteins. The sequence of amino acids along the main, continuous line is that found in the Antp homeobox. At points where the sequence of ftz proteins is different, the differences are shown above the corresponding Antp proteins, and at points where the sequence of... 

As anticipated from the means of isolation, the cad homeobox shows a high degree of homology to the Hox homeobox family, being most related to Antennapedia (Ant) homeobox sequences (62% homology). Hox genes are clustered in two complexes in Drosophila, the BX-C and the ANT-C (reviewed in Lewis 1978 Popadic et al., 1998 Mann and Morata 2000). However, cad is not linked to either of these loci and is therefore not classified as a Hox gene per se. 

Fig. 3. Homology between murine Cdx family members. Regions of conservation between Cdxl, Cdx2, and Cdx3 proteins are indicated. Note also the extended homology flanking the homeobox sequences.

Holland, P.W.H. and Williams, N.A., Conservation of engrailed-like homeobox sequences during vertebrate evolution, FEES Lett., Ill, 250-252, 1990. 

H-NEs, see Historical-narrative explanations Homeobox sequence, 266, 269 Homeotic genes, 269 Homodynamy, 202 Homogeny, 198, 199, 201 Homologue(s)... 

McGinnis, W. (1985) Homeobox sequences of the antennapedia class are conserved only in higher animal genomes . Cold Spring Harbor Symposia on Quantitative Biology, 50, 263-70. 

Homeoboxes code for homeodomains, sequences of 60 amino acids that function as the DNA-binding regions of transcription factors. Each homeo-box gene in Drosophila is expressed only in its own characteristic subset of embryonic cells, and almost every embryonic cell contains a unique combination of homeodomain proteins. 

The amino acid sequence encoded by the homeobox includes a helix-tum-helix motif that has now been shown by X-ray crystallography to be structurally virtually identical to that found in various prokaryotic... 

The genes with paired boxes often, but not always, have homeoboxes as well. The homeoboxes that are associated with paired boxes have distinctive sequence characteristics that set them apart as a separate homeobox subfamily. Interestingly, these paired-type homeoboxes in mouse can sometimes reside on genes such as the K-2 (MHox) and S-8 paired-type homeobox genes, which have not been found to carry paired boxes. 

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