title: Position effect variegation and viability are both sensitive to dosage of constitutive heterochromatin in Drosophila.
abstract: The dosage effect of Y-chromosome heterochromatin on suppression of position effect variegation (PEV) has long been well-known in Drosophila. The phenotypic effects of increasing the overall dosage of Y heterochromatin have also been demonstrated; hyperploidy of the Y chromosome produces male sterility and many somatic defects including variegation and abnormal legs and wings. This work addresses whether the suppression of position effect variegation (PEV) is a general feature of the heterochromatin (independent of the chromosome of origin) and whether a hyperdosage of heterochromatin can affect viability. The results show that the suppression of PEV is a general feature of any type of constitutive heterochromatin and that the intensity of suppression depends on its amount instead of some mappable factor on it. We also describe a clear dosage effect of Y heterochromatin on the viability of otherwise wild-type embryos and the modification of that effect by a specific gene mutation. Together, our results indicate that the correct balance between heterochromatin and euchromatin is essential for the normal genome expression and that this balance is genetically controlled.
authors: Dipartimento di Biologia, Università degli studi di Bari "Aldo Moro," 70125 Bari, Italy.
authors: Maria
authors: M
authors: Berloco
authors: Dipartimento di Biologia, Università degli studi di Bari "Aldo Moro," 70125 Bari, Italy.
authors: Gioacchino
authors: G
authors: Palumbo
authors: Istituto Pasteur, Fondazione Cenci Bolognetti and Dipartimento di Biologia e Biotecnologie "Charles Darwin," Sapienza Università di Roma, 00185 Roma, Italy.
authors: Lucia
authors: L
authors: Piacentini
authors: Istituto Pasteur, Fondazione Cenci Bolognetti and Dipartimento di Biologia e Biotecnologie "Charles Darwin," Sapienza Università di Roma, 00185 Roma, Italy.
authors: Sergio
authors: S
authors: Pimpinelli
authors: Istituto Pasteur, Fondazione Cenci Bolognetti and Dipartimento di Biologia e Biotecnologie "Charles Darwin," Sapienza Università di Roma, 00185 Roma, Italy laura.fanti@uniroma1.it.
authors: Laura
authors: L
authors: Fanti
mesh_terms: D000818:Animals; D004330:Drosophila / Q000235:genetics*; D022041:Euchromatin / Q000235:genetics; D005260:Female; D006570:Heterochromatin / Q000235:genetics*; D008297:Male; D014960:X Chromosome; D014998:Y Chromosome
chemical_list: D022041:Euchromatin; D006570:Heterochromatin
keywords: Drosophila; PEV; heterochromatin; viability