Reorganization of the nuclear architecture in the Drosophila melanogaster Lamin B mutant lacking the CaaX box.
Lamins interact with the nuclear membrane and chromatin but the precise players and mechanisms of these interactions are unknown. Here, we tested whether the removal of the CaaX motif from Lamin B disrupts its attachment to the nuclear membrane and affects chromatin distribution. We usedDrosophila melanogaster Lam  homozygous mutants that lack the CaaX box. We found that the mutant Lamin B was not confined to the nuclear periphery but was distributed throughout the nuclear interior, colocalizing with chromosomes in salivary gland and proventriculus. The peripheral position of Lamin C, nuclear pore complex (NPC), heterochromatin protein 1a (HP1a), H3K9me2- and H3K27me3-associated chromatin remained intact. The fluorescence intensity of the DAPI-stained peripheral chromatin significantly decreased and that of the central chromatin significantly increased in the proventriculus nuclei of the mutantflies compared to wild-type. However, the mutation had little effect on chromatin radial distribution inside highly polytenized salivary gland nuclei.
['Bondarenko|Semen M|SM|0000-0003-0753-581X', 'Sharakhov|Igor V|IV|0000-0003-0752-3747']
D000818:Animals D002843:Chromatin D000090266:Chromobox Protein Homolog 5 D002868:Chromosomal Proteins, Non-Histone D029721:Drosophila Proteins D004331:Drosophila melanogaster D006657:Histones D006720:Homozygote D034921:Lamin Type B D034882:Lamins D009154:Mutation D022022:Nuclear Pore
Drosophila Lamin B chromatin proventriculus nuclei salivary gland nuclei Dm0 Lama25  mutant B-type lamin Nuclear lamina confocal microscopy nuclear envelope