Conserved Site

Homeobox protein, antennapedia type, conserved site (IPR001827)

Short name: Homeobox_Antennapedia_CS


The homeobox is a 60-residue motif first identified in a number of Drosophila homeotic and segmentation proteins, but now known to be well-conserved in many other animals, including vertebrates [PMID: 1357790, PMID: 2568852]. Proteins containing homeobox domains are likely to play an important role in development - most are known to be sequence-specific DNA-binding transcription factors. The domain binds DNA through a helix-turn-helix (HTH) structure.

Many homeodomain-containing proteins have now been sequenced and, while the homeodomain flanking regions vary, characteristic conserved sequences upstream of the domain allow the proteins to be grouped into 3 subfamilies: the so-called antennapedia, engrailed and 'paired box' proteins. Antennapedia, which regulates the formation of leg structures in Drosophila, was one of the first homeotic genes studied and led to the discovery of the homeobox domain. Over expression of this gene in the wrong segment of the fruit fly can lead to the formation of leg structures in these segments. For example, over expression in the head segment can lead to the formation of legs instead of antennae (hence the name antennapedia). The sequences of the antennapedia proteins contain a conserved hexapeptide 5-16 residues upstream of the homeobox, the specific function of which is unclear. The six Drosophila proteins that belong to this group are antennapedia (Antp), abdominal-A (abd-A), deformed (Dfd), proboscipedia (pb), sex combs reduced (scr) and ultrabithorax (ubx) and are collectively known as the 'antennapedia' subfamily.

In vertebrates the corresponding Hox genes are known [PMID: 1358459] as Hox-A2, A3, A4, A5, A6, A7, Hox-B1, B2, B3, B4, B5, B6, B7, B8, Hox-C4, C5, C6, C8, Hox-D1, D3, D4 and D8.

Caenorhabditis elegans lin-39 and mab-5 are also members of the 'antennapedia' subfamily.

Arg and Lys are most frequently found in the last position of the hexapeptide; other amino acids are found in only a few cases.

GO terms

Biological Process

GO:0006355 regulation of transcription, DNA-templated

Molecular Function

GO:0003677 DNA binding
GO:0003700 DNA-binding transcription factor activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns