Drosophila chromosome condensation proteins Topoisomerase II and Barren colocalize with Polycomb and maintain Fab-7 PRE silencing

Rossella Lupo, Achim Breiling, Marco E. Bianchi, Valerio Orlando*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

103 Scopus citations


Mechanisms of cellular memory control the maintenance of cellular identity at the level of chromatin structure. We have investigated whether the converse is true; namely, if functions responsible for maintenance of chromosome structure play a role in epigenetic control of gene expression. We show that Topoisomerase II (TOPOII) and Barren (BARR) interact in vivo with Polycomb group (PcG) target sequences in the bithorax complex of Drosophila, including Polycomb response elements. In addition, we find that the PcG protein Polyhomeotic (PH) interacts physically with TOPOII and BARR and that BARR is required for Fab-7-regulated homeotic gene expression. Conversely, we find defects in chromosome segregation associated with ph mutations. We propose that chromatin condensation proteins are involved in mechanisms acting in interphase that regulate chromosome domain topology and are essential for the maintenance of gene expression.

Original languageEnglish (US)
Pages (from-to)127-136
Number of pages10
JournalMolecular cell
Issue number1
StatePublished - 2001
Externally publishedYes

Bibliographical note

Funding Information:
We particularly thank Laura Fanti and Sergio Pimpinelli for precious advices in the ph and mitotic chromosome experiments, Tatiana Boikova for helping with BX-C subcloning, and Nicola Collu for technical assistance. We are grateful to Hugo Bellen, Manzoor Bhat, Francois Karch, Jean-Maurice Dura, and Renato Paro for fly stocks; Donna Arndt-Jovin, Renato Paro, and Manzoor Bhat for sharing, respectively, anti-TOPOII, anti-PC, and anti-BARR antisera; and Giovanni Capranico for stimulating discussions. This work was supported by AIRC, TELETHON (A125), and EU-TMR (ERBFMRXCT98-0191). A. B. is a EU-TMR fellow. This work is dedicated to the memory of Antonio Ruberti.

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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