title: Characterization of sequences associated with position-effect variegation at pericentric sites in Drosophila heterochromatin.
abstract: In a variety of organisms, euchromatic genes brought into juxtaposition with pericentric heterochromatin show position-effect variegation (PEV), a silencing of gene expression in a subset of the cells in which the gene is normally expressed. Previously, a P-element mobilization screen identified transgenic Drosophila stocks showing PEV of an hsp70-white+ reporter gene; transgenes in many of these stocks map to the chromocenter of polytene chromosome. A screen at an elevated temperature identified two stocks that under standard culture temperatures show complete repression of the hsp70-white+ transgene. The transgenes in both cases map to the chromocenter of polytene chromosomes. Different types of middle repetitive elements are adjacent to seven pericentric transgenes; unique sequences are adjacent to two of the perimetric transgenes. All of the transgenes show suppression of PEV in response to a mutation in the gene encoding heterochromatin protein 1 (HP1). This suppression correlates with a more accessible chromatin structure. The results indicate that a pericentric transgene showing PEV can be associated with different types of DNA sequences, while maintaining a common association with the chromosomal protein HP1.
authors.affiliation: Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Cryderman
authors.forename: M H
authors.initials: MH
authors.lastname: Cuaycong
authors.forename: S C
authors.initials: SC
authors.lastname: Elgin
authors.forename: L L
authors.initials: LL
authors.lastname: Wallrath
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000818:Animals; D030801:Animals, Genetically Modified; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005127:Eye Color / Q000235:genetics; D005136:Eye Proteins; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D006570:Heterochromatin / Q000235:genetics*; D019476:Insect Proteins / Q000235:genetics; D008297:Male; D009154:Mutation; D012091:Repetitive Sequences, Nucleic Acid; D019076:Transgenes
chemical_list: D018528:ATP-Binding Cassette Transporters; D002868:Chromosomal Proteins, Non-Histone; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D005136:Eye Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D006570:Heterochromatin; C087442:Hsp26 protein, Drosophila; D019476:Insect Proteins; C059254:w protein, Drosophila; D000090266:Chromobox Protein Homolog 5