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Hydrobiologia

, Volume 383, Issue 1–3, pp 125–130 | Cite as

Synchronous and early activation of planarian Hox genes and the re-specification of body axes during regeneration in Dugesia (G.) tigrina (Turbellaria; Tricladida)

  • J. R. Bayascas
  • E. Castillo
  • A.M. Muñoz-Mármol
  • J. Baguñà
  • E. Saló
Article

Abstract

Seven Hox cluster-related genes (Dthox-A to -G) have been isolated from the freshwater triclad Dugesia (G.) tigrina, their sequence compared to other Hox genes and their expression in intact and regenerating organisms analyzed by whole mount in situ hybridization. Sequence comparison analyses show high similarities of D. tigrina Hox genes to anterior and medial groups of coelomate Hox genes. Expression analyses show very early, synchronous, and overlapping expression of Dthox -A, -E, -G and -F in anterior, posterior and lateral regenerative tissues. At one hour of regeneration all Dthox genes studied showed a neat, clear expression at the wound boundary. Later, as the blastema grows, the expression area expands to more proximal regions covering the blastema and the distal postblastema regions. Blastemas formed by intercalary regeneration also show a synchronous expression of the same Hox genes though the onset of activation is much delayed. The finding that the same set of Hox genes is synchronously activated in anterior, posterior, intercalary and lateral regeneration is in sharp contrast to its well established role in specifying antero-posterior pattern during embryonic development. The implications of these results as regards ancestral versus co-opted roles of Hox genes in development and regeneration are discussed.

Planarian Hox gene expression 

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References

  1. Averof, M. & M. Akam, 1995. Hox genes and the diversification of insect and crustacean body plans. Nature 376: 420–423.PubMedCrossRefGoogle Scholar
  2. Baguñà, J., 1981. Planarian neoblasts. Nature 290: 14–15.CrossRefGoogle Scholar
  3. Baguñà, J., E. Saló & M. C. Auladell, 1989. Regeneration and pattern formation in planarians. III. Evidence that neoblasts are totipotent stem cells and the source of blastema cells. Development 107: 77–86.Google Scholar
  4. Baguñà, J., E. Saló, R. Romero, J. Garcia-Fernàndez, D. Bueno, A. Muñoz-Mármol, J. R. Bayascas-Ramírez & A. Casali, 1994. Regeneration and pattern formation in planarians: cells, molecules and genes. Zool. Sci. 11: 781–795.Google Scholar
  5. Balavoine G., 1997. The early emergence of platyhelminths is contradicted by the agreement between 18S rRNA and Hox genes data. C.r. Acad. Sci., Paris 320: 83–94.Google Scholar
  6. Bayascas JR, E. Castillo, A.M. Muñoz-Mármol, E. Saló, 1997. Planarian Hox genes: novel patterns of expression during regeneration. Development 124: 141–148.PubMedGoogle Scholar
  7. Brønsdted, H. V., 1969. Planarian Regeneration. Pergamon Press, London.Google Scholar
  8. Carroll, S. B., 1995. Homeotic genes and the evolution of arthropods and chordates. Nature 376: 478–485.CrossRefGoogle Scholar
  9. Deveraux JP, P. Haeberli, O. Smithies, 1984. A comprehensive set of sequence analysis programs for the VAX. Nucl. Acids Res. 12: 387–395.Google Scholar
  10. Duboule, D., 1994. Temporal colinearity and the phylotypic progression: a basis for the stability of a vertebrate Bauplan and evolution of morphologies through heterochrony. Development Suppl., 135–142.Google Scholar
  11. Gardiner, D. M., B. Blumberg, Y. Komine & S. V. Bryant, 1995. Regulation of Hox-A expression in developing and regenerating axolotl limbs. Development 121: 1731–1741.PubMedGoogle Scholar
  12. Gardiner, D.M. & S. V. Bryant, 1996. Molecular mechanisms in the control of limb regeneration: the role of homeobox genes. Int. J. Dev. Biol 40: 797–805.PubMedGoogle Scholar
  13. Holland, P. W. H., 1993. Cloning genes using the polymerase chain reaction. In C. D. Stern & P. W. H. Holland (eds), Essential Developmental Biology. A Practical Approach. IRL Press, Oxford: 243–255.Google Scholar
  14. Kenyon, C., 1994. If birds can fly, why can't we? Homeotic genes and evolution. Cell 78: 175–180.PubMedCrossRefGoogle Scholar
  15. Krumlauf, R., 1994. Hox genes in vertebrate development. Cell 78: 191–201.PubMedCrossRefGoogle Scholar
  16. Lawrence, P. A. & G. Morata, 1994. Homeobox genes: their function in Drosophila segmentation and pattern formation. Cell 78: 181–189.PubMedCrossRefGoogle Scholar
  17. Ribas, M., M. Riutort & J. Baguñà, 1989. Morphological and biochemical variation in populations of Dugesia (G.) tigrina (Turbellaria, Tricladida, Paludicola) from the western Mediterranean: biogeographical and taxonomical implications. J. Zool., London 218: 609–626.CrossRefGoogle Scholar
  18. Saló, E. & J., Baguñà, 1984. Regeneration and pattern formation in planarians. I. The pattern of mitosis in anterior and posterior regeneration inDugesia (G.) tigrina, and a new proposal for blastema formation. J. Embryol. exp. Morph. 83: 63–80.PubMedGoogle Scholar
  19. Saló, E. & J., Baguñà, 1985. Proximal and distal transformation during intercalary regeneration in the planarian Dugesia (G) tigrina. Roux's Arch. Dev. Biol. 194: 364–368.CrossRefGoogle Scholar
  20. Saló, E. & J. Baguñà. 1989. Regeneration and pattern formation in planarians. II. Local origin and role of cell movements in blastema formation. Development 107: 69–76.Google Scholar
  21. Saló, E., A. M. Muñoz-Mármol, J. R. Bayascas-Ramirez, J. Garcia-Fernàndez, A. Miralles, A. Casali, M. Corominas & J. Baguñà, 1995. The freshwater planarian Dugesia (G.) tigrina contains a great diversity of homeobox genes. Hydrobiologia 305: 269–275.CrossRefGoogle Scholar
  22. Tauler J, Baguñà J, E. Saló, J. Garcia-Fernàndez, 1996. Distox genes: A milestone in the evolution of HOX clusters? Int. J. Dev. Biol. Suppl. 1: 69S.PubMedGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • J. R. Bayascas
    • 1
  • E. Castillo
    • 2
  • A.M. Muñoz-Mármol
    • 2
  • J. Baguñà
    • 2
  • E. Saló
    • 2
  1. 1.Departament de Genètica, Facultat de BiologiaUniversitat de Barcelona.BarcelonaSpain
  2. 2.Departament de Genètica, Facultat de BiologiaUniversitat de Barcelona.BarcelonaSpain

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