, Volume 117, Issue 1, pp 25–39 | Cite as

The trithorax group and Pc group proteins are differentially involved in heterochromatin formation in Drosophila

  • Laura FantiEmail author
  • Barbara Perrini
  • Lucia Piacentini
  • Maria Berloco
  • Enzo Marchetti
  • Gioacchino Palumbo
  • Sergio PimpinelliEmail author
Research Article


In Drosophila, the Polycomb group and trithorax group proteins play a critical role in controlling the expression states of homeotic gene complexes during development. The common view is that these two classes of proteins bind to the homeotic complexes and regulate transcription at the level of chromatin. In the present work, we tested the involvement of both groups in mitotic heterochromatin formation in Drosophila. Using specific antibodies, we show that some of the tested Pc-G proteins are present in heterochromatin, while all the tested trx-G proteins localize to specific regions of heterochromatin in both mitotic chromosomes and interphase nuclei. We also observed that mutations in trx-G genes are recessive enhancers of position-effect variegation and are able to repress the transcription of heterochromatic genes. These results strongly suggest that trx-G proteins, along with some Pc-G proteins, play an active role in heterochromatin formation in Drosophila.


Polytene Chromosome Mitotic Chromosome Heterochromatic Region Homeotic Gene Heterochromatin Formation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We thank K. Golic G. Karpen, T. Lyttle for their comments on manuscript. We thank C. Goday for the useful suggestions in elaborating some of the immunostaining procedures. We thank G. Cavalli, J. Eissenberg, M. Gatti, R. Johns, R. Paro, G. Reuter, A. Shearn, J. Tamkun, and Bloomington Stocks Center for the mutant Drosophila strains. We thank K. Ahmad, S. Elgin, P. Harte, S. Henikoff, R. Johns, G. Karpen, J. Kassis, A. Mazo, R. Paro, V. Pirrotta, A. G. Reuter, A. Shearn, J. Tamkun, C. Wu for antibodies.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Laura Fanti
    • 1
    Email author
  • Barbara Perrini
    • 1
  • Lucia Piacentini
    • 1
  • Maria Berloco
    • 2
  • Enzo Marchetti
    • 1
  • Gioacchino Palumbo
    • 2
  • Sergio Pimpinelli
    • 1
    Email author
  1. 1.Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Genetica e Biologia molecolareUniversità “La Sapienza”RomeItaly
  2. 2.Dipartimento di Genetica e MicrobiologiaUniversità di BariBariItaly

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