ABSTRACT
Modular gold amide chemotherapeutics: Access to modern chemotherapeutics with robust and flexible synthetic routes that are amenable to extensive customisation is a key requirement in drug synthesis and discovery. A class of chiral gold amide complexes featuring amino acid derived ligands is reported herein. They all exhibit in vitro cytotoxicity against two slow growing breast cancer cell lines with limited toxicity towards normal epithelial cells.
Subject(s)
Amides/chemistry , Antineoplastic Agents/pharmacology , Gold/chemistry , Organogold Compounds/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Epithelial Cells/drug effects , Humans , Molecular Structure , Nigericin/pharmacology , Organogold Compounds/chemical synthesis , Organogold Compounds/chemistry , Structure-Activity RelationshipABSTRACT
Cells coordinate spindle formation with DNA repair and morphological modifications to chromosomes prior to their segregation to prevent cell division with damaged chromosomes. Here we uncover a novel and unexpected role for Aurora kinase in preventing the formation of spindles by Clb5-CDK (S-CDK) during meiotic prophase I and when the DDR is active in budding yeast. This is critical since S-CDK is essential for replication during premeiotic S-phase as well as double-strand break induction that facilitates meiotic recombination and, ultimately, chromosome segregation. Furthermore, we find that depletion of Cdc5 polo kinase activity delays spindle formation in DDR-arrested cells and that ectopic expression of Cdc5 in prophase I enhances spindle formation, when Ipl1 is depleted. Our findings establish a new paradigm for Aurora kinase function in both negative and positive regulation of spindle dynamics.
Subject(s)
Aurora Kinases/metabolism , Chromosomes, Fungal/metabolism , Cyclin B/metabolism , Meiotic Prophase I , Saccharomyces cerevisiae Proteins/metabolism , Spindle Apparatus/metabolism , Cell Cycle Proteins/metabolism , Cell Nucleus/genetics , Cell Nucleus/metabolism , Chromosomes, Fungal/genetics , DNA Damage , DNA-Binding Proteins/metabolism , Mutation , Phosphorylation , Protein Serine-Threonine Kinases/metabolism , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/enzymology , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Spindle Apparatus/genetics , Transcription, GeneticABSTRACT
During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4(Eme1). Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastrophe.
