Drosophila homeodomain

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. 

Figure 9.11 Amino acid sequences of homeodomains from four differenf franscription factors Anfp is from fhe Antennapedia gene in the fruitfly Drosophila, a2 is from the yeast Mat o2 gene, eng is from fhe engrailed gene in Drosophila and POU is from fhe POU homeodomain in the mammalian gene Oct-1. Residues colored green form the hydrophobic core of the homeodomain, blue form nonspecific interactions with the DNA backbone and red form contacts with the edges of the DNA bases.

Fortini, M. E., Lai, Z., and Rubin, G. M. (1991). The Drosophila zfli-1 and zfli-2 genes encode novel proteins containing both zinc-finger and homeodomain motifs. Mech. Dev. 34 113-122. 

An interesting case of regulation at the translation level was discovered on the example of the homeodomain protein bicoid (bed), which is important in Drosophila differentiation (Dubnau and Struhl, 1996). The bicoid protein is a transcriptional activator that binds a cognate DNA element and stimulates the transcription of the neighboring genes. Apart from its specific DNA-binding capabUity, the bicoid protein binds to 3 -, non-translating sequences of the mRNA of another homeodomain protein (caudal protein) to inhibit its translation. 

Human (Homo sapiens) Escherichia coli Aspergillus awamori, variant xlOO engrailed Homeodomain Drosophila melanogaster... 

Han K, Jeon MJ, Kim KA, Park J, Choi SY. Efficient intracellular delivery of GFP by homeodomains of Drosophila Fushi-tarazu and Engrailed proteins. Mol Cells 2000 10 728-32. 

Penetratin Drosophila antennapedia homeodomain RQIKIWFQNRRMKWKK Cationic Y 108... 

Chiang, C., Patel, N., Young, K., and Beachy, P. (1994). The novel homeodomain gene buttonless specifies differentiation and axonal guidance functions of Drosophila dorsal median cells. 

Copeland, J.W., Nasiadka, A., Dietrich, B.H., Krause, H.M. 1996. Patterning of the Drosophila embryo by a homeodomain-deleted Ftz polypeptide. Nature 379, 162-165. 

Fitzpatrick, V.D., Percival-Smith, A., Ingles, C.J., Krause, H.M. 1992. Homeodomain-independent activity of the fushi tarazu polypeptide in Drosophila embryos. Nature 356, 610-612. 

Johnson, F.B., Parker, E., Krasnow, M.A. 1995. Extradenticle protein is a selective cofactor for the Drosophila homeotics Role of the homeodomain and YPWM amino acid motif in the interaction. Proc. Natl. Acad. Sci. USA 92, 739-743. 

Kuziora, M.A., McGinnis, W. 1991. Altering the regulatory targets of the Deformed protein in Drosophila embryos by substituting the Abdominal-B homeodomain. Mech. Dev. 33, 83-94. 

Walter, J., Biggin, M.D. 1996. DNA binding specificity of two homeodomain proteins in vitro and in Drosophila embryos. Proc. Natl. Acad. Sci. USA 93, 2680-2685. 

Cdx (caudal) family members encode homeodomain transcription factors. The name caudal derives from the essential function of the gene product in the development of the posterior Drosophila embryo, a role that appears generally conserved across species. In vertebrates, Cdx proteins perform essential functions in the trophoblast, intestinal development, posterior specification and vertebral patterning. While this review focuses largely on the function of murine Cdx homologues, a number of relevant findings have been established initially from other systems, and will be briefly discussed. 

Gamer, L.W., Wright, C.V. 1993. Murine Cdx-4 bears striking similarities to the Drosophila caudal gene in its homeodomain sequence and early expression pattern. Mech. Dev. 43, 71-81. 

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