Berloco, M., Palumbo, G., Piacentini, L., Pimpinelli, S., Fanti, L. (2014). Position effect variegation and viability are both sensitive to dosage of constitutive heterochromatin in Drosophila.  G3 (Bethesda) 4(9): 1709--1716.

FBrf0226242

Research paper

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.

PMC4169164 (PMC) (EuropePMC)