Lysophosphatidylcholine Analogues Alter Yeast Nuclear Envelope Architecture and Function

Abstract

The lysophosphatidylcholine analog edelfosine is an anticancer lipid drug that targets cellular membranes. Therefore, it is alleged that in contrast to other chemotherapeutic agents edelfosine does not impact DNA. Despite this claim, a genetic screen in Saccharomyces cerevisiae found that lack of silent information regulator (Sir) proteins, alleviated the toxic effect of edelfosine. Since Sir proteins are key architects and regulators of the genome, we decided to investigate if this unusual connection with edelfosine could be related to a potential effect of the lysophosphatidylcholine analog on the nuclear envelope (NE) structure and function. Indeed, we found that edelfosine alters NE morphology, leading to an abnormal elongation of the membrane. Since it is known that Sir proteins mediate tethering of subtelomeric chromatin to the NE, we investigated if this was affected by treatment of wild type cells with the drug. Results from chromatin immunoprecipitation of Sir4 showed a significant reduction in the association of the protein with telomeres when cells were treated with edelfosine. Current evidence also supports alterations of telomere clustering in the presence of the lysophosphatidylcholine analogue. Therefore, our results suggest that edelfosine alters NE morphology and function. We speculate that mislocalization of Sir proteins in the nucleus probably results in abnormal silencing of genes that may be implicated in pathways that confer resistance to this lysophosphatidylcholine analog.Support or Funding InformationThis work has been financially supported by the Natural Sciences and Engineering Research Council of Canada to V Zaremberg and JA Cobb.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.