Xrp1 genetically interacts with the ALS-associated FUS orthologue caz and mediates its toxicity

In this study, we identified Xrp1, a nuclear chromatin-binding protein, as a key modifier of caz mutant phenotypes. Xrp1 expression was strongly up-regulated in caz mutants, and Xrp1 heterozygosity rescued their motor defects and life span. Interestingly, selective neuronal Xrp1 knockdown was sufficient to rescue, and neuronal Xrp1 overexpression phenocopied caz mutant phenotypes. The caz/Xrp1 genetic interaction depended on the functionality of the AT-hook DNA-binding domain in Xrp1, and the majority of Xrp1-interacting proteins are involved in gene expression regulation. Consistently, caz mutants displayed gene expression dysregulation, which was mitigated by Xrp1 heterozygosity. Finally, Xrp1 knockdown substantially rescued the motor deficits and life span of flies expressing ALS mutant FUS in motor neurons, implicating gene expression dysregulation in ALS-FUS pathogenesis.

Source: Journal of Cell Biology - November 5, 2018 Category: Cytology Authors: Mallik, M., Catinozzi, M., Hug, C. B., Zhang, L., Wagner, M., Bussmann, J., Bittern, J., Mersmann, S., Klämbt, C., Drexler, H. C. A., Huynen, M. A., Vaquerizas, J. M., Storkebaum, E. Tags: Chromatin or Epigenetics, DNA Biology, Neuroscience Articles Source Type: research