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Gene Review

twi  -  twist

Drosophila melanogaster

Synonyms: CG2956, DTwist, Dmel\CG2956, EC9, Protein twist, ...
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High impact information on twi

  • To initiate the differentiation of the mesoderm in Drosophila, multiple zygotic genes such as twist (twi) and snail (sna), which encode a basic-helix-loop-helix and a zinc finger transcription factor, respectively, are required [1].
  • This is explained by results showing that dCBP is necessary for dl-mediated activation of the twi promoter [1].
  • The transcription factor Twist initiates Drosophila mesoderm development, resulting in the formation of heart, somatic muscle, and other cell types [2].
  • Altering amounts of Twist after gastrulation revealed that high levels of Twist are required for somatic myogenesis and block the formation of other mesodermal derivatives [3].
  • The bHLH protein Twist is expressed throughout the epithelial somite and is subsequently excluded from the myotome [4].

Biological context of twi

  • Linear signaling in the Toll-Dorsal pathway of Drosophila: activated Pelle kinase specifies all threshold outputs of gene expression while the bHLH protein Twist specifies a subset [5].
  • Transgenes misexpressing Pelle and Twist were introduced into different mutant backgrounds and the patterning activities were visualized using various target genes that respond to different thresholds of Toll-Dorsal signaling [5].
  • A two-step procedure in which maternally expressed sequences were subtracted from each of these cDNA libraries, before subtracting twi from wild-type, increased the subtraction efficiency [6].
  • Here we show that Dorsal and the bHLH activator Twist synergistically activate transcription in cell culture and in vitro from a promoter containing binding sites for both factors [7].
  • Nonetheless, the regions of Twist and Dorsal required for the binding interaction are also required for synergistic transcriptional activation [7].

Anatomical context of twi

  • Two zygotic genes, snail (sna) and twist (twi), are required for mesoderm development, which begins with the formation of the ventral furrow [8].
  • Both twi and sna are expressed ventrally in the blastoderm, encode transcription factors and promote the invagination of the ventral furrow by activating or repressing appropriate target genes [8].
  • In the third instars discs, in the vicinity of tendon progenitors, some Twist-positive myoblasts start to express the muscle founder cell marker dumbfounded (duf) [9].
  • It is novel and its expression is mesoderm-specific, twi-dependent, and early during somatic, visceral, and heart muscle differentiation [6].
  • High Twist levels direct cells to the body wall muscle fate, whereas low levels are permissive for gut muscle and fat body fate [10].

Physical interactions of twi

  • Using a combination of promoter fusion-P-transformation assays, and in vitro DNA-binding assays coupled with site-directed mutagenesis, we establish a direct link between dl-binding sites and twi expression in the early embryo [11].

Regulatory relationships of twi

  • The expression of wntD is activated by Dorsal and Twist, but the expression is much reduced in the ventral cells through repression by Snail [12].
  • We show that Su(H)-mediated Notch signaling represses Twist expression during subdivision and thus plays a critical role in patterning mesodermal segments [10].
  • We present evidence that dl and twi directly activate sna expression [13].
  • We provide evidence that ap ectopic expression can induce per se ectopic twi expression and muscle degeneration [14].
  • Dip3 functions as a coactivator to stimulate synergistic activation by Dorsal and Twist, but does not stimulate simple activation of promoters containing only Dorsal or only Twist binding sites [15].

Other interactions of twi

  • In the anterior part, hkb antagonizes the activation of target genes by twi and sna [8].
  • We investigate the activities of the Pelle kinase and Twist basic helix-loop-helix (bHLH) transcription factor in transducing Toll signaling [5].
  • We discuss how the Dorsal gradient system can be modified during metazoan evolution and conclude that Dorsal-Twist interactions are distinct from the interplay between Bicoid and Hunchback, which pattern the anteroposterior axis [5].
  • Our work demonstrates that Notch acts as a transcriptional switch on mesodermal target genes, and it suggests that Notch/Su(H) directly regulates twist, as well as indirectly regulating twist by activating proteins that repress Twist [10].
  • The combination of a common set of mesoderm autonomous transcription factors (e.g. Tinman and Twist) and spatially restricted inductive signals (e.g. Dpp and Wg) subdivide the dorsal mesoderm into different competence domains [16].

Analytical, diagnostic and therapeutic context of twi

  • During Drosophila gastrulation, apical constrictions under the control of the transcription factor Twist lead to the invagination of the mesoderm [17].


  1. Drosophila CBP is required for dorsal-dependent twist gene expression. Akimaru, H., Hou, D.X., Ishii, S. Nat. Genet. (1997) [Pubmed]
  2. Patterns of gene expression during Drosophila mesoderm development. Furlong, E.E., Andersen, E.C., Null, B., White, K.P., Scott, M.P. Science (2001) [Pubmed]
  3. twist: a myogenic switch in Drosophila. Baylies, M.K., Bate, M. Science (1996) [Pubmed]
  4. Inhibition of myogenic bHLH and MEF2 transcription factors by the bHLH protein Twist. Spicer, D.B., Rhee, J., Cheung, W.L., Lassar, A.B. Science (1996) [Pubmed]
  5. Linear signaling in the Toll-Dorsal pathway of Drosophila: activated Pelle kinase specifies all threshold outputs of gene expression while the bHLH protein Twist specifies a subset. Stathopoulos, A., Levine, M. Development (2002) [Pubmed]
  6. A novel Drosophila, mef2-regulated muscle gene isolated in a subtractive hybridization-based molecular screen using small amounts of zygotic mutant RNA. Taylor, M.V. Dev. Biol. (2000) [Pubmed]
  7. A direct contact between the dorsal rel homology domain and Twist may mediate transcriptional synergy. Shirokawa, J.M., Courey, A.J. Mol. Cell. Biol. (1997) [Pubmed]
  8. Interacting functions of snail, twist and huckebein during the early development of germ layers in Drosophila. Reuter, R., Leptin, M. Development (1994) [Pubmed]
  9. Coordinated development of muscles and tendons of the Drosophila leg. Soler, C., Daczewska, M., Da Ponte, J.P., Dastugue, B., Jagla, K. Development (2004) [Pubmed]
  10. Notch signaling patterns Drosophila mesodermal segments by regulating the bHLH transcription factor twist. Tapanes-Castillo, A., Baylies, M.K. Development (2004) [Pubmed]
  11. The dorsal morphogen gradient regulates the mesoderm determinant twist in early Drosophila embryos. Jiang, J., Kosman, D., Ip, Y.T., Levine, M. Genes Dev. (1991) [Pubmed]
  12. Drosophila WntD is a target and an inhibitor of the Dorsal/Twist/Snail network in the gastrulating embryo. Ganguly, A., Jiang, J., Ip, Y.T. Development (2005) [Pubmed]
  13. dorsal-twist interactions establish snail expression in the presumptive mesoderm of the Drosophila embryo. Ip, Y.T., Park, R.E., Kosman, D., Yazdanbakhsh, K., Levine, M. Genes Dev. (1992) [Pubmed]
  14. Control of apterous by vestigial drives indirect flight muscle development in Drosophila. Bernard, F., Lalouette, A., Gullaud, M., Jeantet, A.Y., Cossard, R., Zider, A., Ferveur, J.F., Silber, J. Dev. Biol. (2003) [Pubmed]
  15. The MADF-BESS domain factor Dip3 potentiates synergistic activation by Dorsal and Twist. Bhaskar, V., Courey, A.J. Gene (2002) [Pubmed]
  16. Integrating transcriptional and signalling networks during muscle development. Furlong, E.E. Curr. Opin. Genet. Dev. (2004) [Pubmed]
  17. Control of Drosophila gastrulation by apical localization of adherens junctions and RhoGEF2. Kölsch, V., Seher, T., Fernandez-Ballester, G.J., Serrano, L., Leptin, M. Science (2007) [Pubmed]
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