Drosophila Embryo: Homeotic Genes in Specification of the Anterior–Posterior Axis


The products of the homeotic genes of Drosophila melanogaster are a set of transcription factors, each with its own unique expression pattern and battery of target genes. It is the combination of these two features by which, as a group, the homeotic genes are capable of specifying the collections of cell types characteristic of different regions of the animal body.

Keywords: embryogenesis; homeotic; homeodomain; segmental identity

Figure 1.

Theorganization and expression of HOM/Hox genes in Drosophilamelanogaster. The diagram shows the embryonic expression pattern andphenotypic result for the nine HOM/Hox genes. The relativechromosomal positions of the ANT‐C and BX‐C genes are shown at the bottom. Theexpression of each gene in a D. melanogaster embryo is shown as acolour‐coded line and shading. The lines represent the approximate extent ofmetameric expression domains. The shading in the embryo is representative ofmodulated expression patterns but is not intended to accurately depict anyspecific time during development. A diagram of a larva shows the diversesegmental identities produced by HOM/Hox gene expression. Ic,intercalary; Mn, mandibular; Mx, maxillary; Lb, labial;dr, dorsal ridge; T1, first thoracic; A1, first abdominal; A8,eighth abdominal; ps, posterior spiracle.

Figure 2.

The HOM/Hoxhomeodomains. The aligned sequences of homeodomains and flanking amino acidsare shown using one letter (AA) code. The helices of thehomeodomain and YPWM motif are marked. Dashes represent spaces introduced intothe sequence to make the alignment, and dots represent amino acids not shown.The Abd‐B and zen homeodomains are shown separate because oftheir divergent homeodomains. Asterisks along the top indicate identical aminoacids for the top seven homeodomains. Asterisks along the bottom markidentical amino acids for all nine homeodomains.



Akam M (1989) Hox and HOM: homologous gene clusters in insects and vertebrates. Cell 57: 347–349.

Andrew DJ, Horner MA, Petitt MG, Smolik SM and Scott MP (1994) Setting limits on homeotic gene function: restraint of Sex combs reduced activity by teashirt and other homeotic genes. EMBO Journal 13: 1132–1144.

Castelli‐Gair JE and Akam M (1995) How the Hox gene Ultrabithorax specifies two different segments: The significance of spatial and temporal regulation within metameres. Development 121: 2973–2982.

Gellon G and McGinnis W (1998) Shaping animal body plans in development and evolution by modulation of Hox expression patterns. BioEssays 20: 116–125.

Graba Y, Arangol D and Pradel J (1997) Drosophila Hox complex downstream targets and the function of homeotic genes. BioEssays 19: 379–388.

Hoppler S and Bienz M (1994) Specification of a single cell type by a Drosophila homeotic gene. Cell 76: 689–702.

Jack TP and McGinnis W (1990) Establishment of the Deformed expression stripe requires the combinatorial action of coordinate, gap and pair‐rule proteins. EMBO Journal 9: 1187–1198.

Kennison JA (1995) The Polycomb and trithorax group proteins of Drosophila: Trans‐regulators of homeotic gene function. Annual Review of Genetics 29: 289–303.

Lewis EB (1994) Homeosis: the first 100 years. Trends in Genetics 10: 341–343.

Lindsley DL and Zimm GG (1990) The Genome of Drosophila melanogaster. New York: Academic Press.

McGinnis W (1994) A century of homeosis, a decade of homeoboxes. Genetics 137: 607–611.

McGinnis N, Ragnhildstveit E, Veraksa A and McGinnis W (1998) A cap ‘n’ collar protein isoform contains a selective Hox repressor function. Development 125: 4553–4564.

Mann RS and Affolter M (1998) Hox proteins meet more partners. Current Opinion in Genetics and Development 8: 423–429.

Michelson AM (1994) Muscle pattern diversification in Drosophila is determined by the autonomous function of homeotic genes in the embryonic mesoderm. Development 120: 755–768.

Prokop A, Bray S, Harrison E and Technau GM (1998) Homeotic regulation of segment‐specific differences in neuroblast numbers and proliferation in the Drosophila central nervous system. Mechanisms of Development 74: 99–110.

Simon J, Peifer M, Bender W and O'Connor M (1990) Regulatory elements of the bithorax complex that control expression along the anterior–posterior axis. EMBO Journal 9: 3945–3956.

Triesman J, Harris E, Wilson D and Desplan C (1992) The Homeodomain: A new face for the helix‐turn‐helix? Bioessays 14: 145–150.

Further Reading

Akam M (1998) Hox genes, homeosis and the evolution of segment identity: No need for hopeless monsters. International Journal of Developmental Biology 42: 445–451.

Bate M and Martinez Arias A (eds) (1993) The Development of Drosophila melanogaster. New York: Cold Spring Harbor Laboratory Press.

Bienz M (1994) Homeotic genes and positional signalling in the Drosophila viscera. Trends in Genetics 10: 22–26.

Castelli‐Gair J, Grieg S, Micklem G and Akam M (1994) Dissecting the temporal requirements for homeotic gene function. Development 120: 1982–1995.

Hayashi S and Scott MP (1990) What determines the specificity of action of Drosophila homeodomain proteins? Cell 63: 883–894.

Kaufman TC, Lewis R and Wakimoto B (1980) Cytogenetic analysis of chromosome 3 in Drosophila melanogaster. The homeotic gene complex in polytene chromosome interval 84A‐B, Genetics 94: 115–133.

Lewis EB (1978) A gene complex controlling segmentation in Drosophila. Nature 276: 565–570.

Morata G (1993) Homeotic genes of Drosophila. Current Opinions in Genetics and Development 3: 606–614.

Tillib S, Petruk S, Sedkov Y et al. (1999) Trithorax‐ and polycomb‐group response elements within an Ultrabithorax transcription maintenance consists of closely situated but separable sequences. Molecular and Cellular Biology 19: 5189–5202.

Vachon G, Cohen B, Pfeifle C, McGuffin ME, Botas J and Cohen SM (1992) Homeotic genes of the Bithorax complex repress limb development in the abdomen of the Drosophila embryo through the target gene Distal‐less. Cell 71: 437–450.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Rogers, Bryan T(Apr 2001) Drosophila Embryo: Homeotic Genes in Specification of the Anterior–Posterior Axis. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0001509]