Position effect variegation and viability are both sensitive to dosage of constitutive heterochromatin in Drosophila.

Maria Berloco (1) , Gioacchino Palumbo (1) , Lucia Piacentini (2) , Sergio Pimpinelli (2) , Laura Fanti (2)

1 UNIBA - Università degli studi di Bari Aldo Moro = University of Bari Aldo Moro
2 Department of Biology and Biotechnology "Charles Darwin"

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.

Domaines: Génétique

Maria Berloco, Gioacchino Palumbo, Lucia Piacentini, Sergio Pimpinelli, Laura Fanti. Position effect variegation and viability are both sensitive to dosage of constitutive heterochromatin in Drosophila.. G3, 2014, 4 (9), pp.1709-16. ⟨10.1534/g3.114.013045⟩. ⟨pasteur-01182751⟩