title: [Distorted heterochromatin replication in Drosophila melanogaster polytene chromosomes as a result of euchromatin-heterochromatin rearrangements].
abstract: Studies of the position effect resulting from chromosome rearrangements in Drosophila melanogaster have shown that replication distortions in polytene chromosomes correlate with heritable gene silencing in mitotic cells. Earlier studies mostly focused on the effects of euchromatin--heterochromatin rearrangements on replication and silencing of euchromatic regions adjacent to the heterochromatin breakpoint. This review is based on published original data and considers the effect of rearrangements on heterochromatin: heterochromatin blocks that are normally underrepresented or underreplicated in polytene chromosomes are restored. Euchromatin proved to affect heterochromatin, preventing its underreplication. The effect is opposite to the known inactivation effect, which extends from heterochromatin to euchromatin. The trans-action of heterochromatin blocks on replication of heterochromatin placed within euchromatin is discussed. Distortions of heterochromatin replication in polytene chromosomes are considered to be an important characteristic associated with the functional role of the corresponding genome regions.
authors.forename: V A
authors.initials: VA
authors.lastname: Gvozdev
authors.forename: Iu A
authors.initials: IuA
authors.lastname: Abramov
authors.forename: G L
authors.initials: GL
authors.lastname: Kogan
authors.forename: S A
authors.initials: SA
authors.lastname: Lavrov
mesh_terms: D000818:Animals; D042002:Chromatin Assembly and Disassembly; D004261:DNA Replication; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D022041:Euchromatin / Q000235:genetics / Q000502:physiology*; D015321:Gene Rearrangement; D006570:Heterochromatin / Q000235:genetics / Q000502:physiology*; D014960:X Chromosome / Q000235:genetics / Q000502:physiology
chemical_list: D022041:Euchromatin; D006570:Heterochromatin