A new role of ATAC-HAT in dosage compensation

Cristina Popescu, I. Boros

Research output: Contribution to journalArticle


In Drosophila similar to other eukaryotes, SAGA and ATAC HAT complexes exhibit different specificities in the targeted histone lysines and have essential but distinct functions as it is shown by the different phenotypes occurring in their absence. Besides Gnc5, Ada3 is also an important member of both types of HAT complexes. Loss of dADA3 function results in similar chromosome structural defects like the dGcn5 and dAda2a. The abnormal polytene chromosome structure of dAda3 mutants is visible most clearly on the X male chromosomes which appear bloated. Immunostaining indicates that the level of dADA3 protein is increased on the wild type male X. Nonetheless, the levels of K16 acetylated histone H4, a marker of dosage compensation is similar both in the mutant and wild type male X chromosomes. ATAC displays a preferential specificity towards acetylating histone H4. Besides already known acetylated lysine's (H4K5 and K12) recent findings suggest a possible role of ATAC in H4K16 acetylation. This marker is well known as being specific for X male chromosome which is double transcribed in males compared to females. We have data that show a 2 fold increase in binding of dAda3 protein was observed on the male X that can be easily associated with increase transcriptional activity on the X. Also, the JIL-1 kinase that is not part of the MOF histone acetyltransferase has been shown to be implicated in dosage compensation. Phosphoryllation of H3 at Serine 10 has been shown to modulate chromosome condensation during mitosis. Reduced phosphorylation of H3S10 can also be observed in ATAC mutants.

Original languageEnglish
Pages (from-to)93-100
Number of pages8
JournalAnnals of the Romanian Society for Cell Biology
Issue number2
Publication statusPublished - Dec 1 2010


  • Ada3
  • Histone acetilation
  • X-male chromosome

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cell Biology

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