Tissue-specific and temporal analysis of nuclear organization through development of a novel FLP/Frt-based toolkit for spatiotemporal control of gene expression

Abstract

The nuclear envelope (NE) plays critical roles in gene expression. Reflecting the importance of its functions, several human diseases are attributed to alterations in NE structure. Most notably are the laminopathies, with one example being Emery-Dreifuss muscular dystrophy, which is caused by mutations in the inner nuclear membrane protein emerin or in the nuclear lamina protein lamin A. On the one hand, we found recently that EMR-1, the Caenorhabditis elegans ortholog of emerin, associates with genes implicated in muscle and nervous system function and regulate their expression. Interestingly, deletion of emr-1 causes local changes in nuclear architecture and hypersensitivity to the cholinesterase inhibitor aldicarb, indicating altered activity at neuromuscular junctions. Although many NE proteins are ubiquitously expressed, laminopathies often affect a single tissue. We hypothesize that tissue-specific alterations in nuclear organization are responsible for particular symptoms of laminopathies. On the other hand, it is known that NE morphology is prone to suffer from changes through normal aging and in progeria patients. Again, we propose that alterations in nuclear organization through development and aging may have an impact on the aging-associated disorders. For these two reasons, changes in interactions between NE proteins and chromatin in a tissue-specific or in a temporal manner are thought to be relevant, but have not been explored in intact organisms due to technical limitations. This triggered us to develop novel DamID tools based on FLP-mediated recombination to dissect the function of EMR-1 in tissue-specific nuclear organization as well as at different stages in the aging process.