A lot about a little dot - Lessons learned from Drosophila melanogaster chromosome 4

Academic Article


  • The fourth chromosome of Drosophila melanogaster has a number of unique properties that make it a convenient model for the study of chromatin structure. Only 4.2 Mb overall, the 1.2 Mb distal arm of chromosome 4 seen in polytene chromosomes combines characteristics of heterochromatin and euchromatin. This domain has a repeat density of ∼35%, comparable to some pericentric chromosome regions, while maintaining a gene density similar to that of the other euchromatic chromosome arms. Studies of position-effect variegation have revealed that heterochromatic and euchromatic domains are interspersed on chromosome 4, and both cytological and biochemical studies have demonstrated that chromosome 4 is associated with heterochromatic marks, such as heterochromatin protein 1 and histone 3 lysine 9 methylation. Chromosome 4 is also marked by POF (painting-of-fourth), a chromosome 4-specific chromosomal protein, and utilizes a dedicated histone methyltransferase, EGG. Studies of chromosome 4 have helped to shape our understanding of hetero-chromatin domains and their establishment and maintenance. In this review, we provide a synthesis of the work to date and an outlook to the future.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Riddle NC; Shaffer CD; Elgin SCR
  • Start Page

  • 229
  • End Page

  • 241
  • Volume

  • 87
  • Issue

  • 1