title: The Natural Product N-Palmitoyl-l-leucine Selectively Inhibits Late Assembly of Human Spliceosomes.
abstract: The spliceosome is a dynamic complex of five structural RNAs and dozens of proteins, which assemble together to remove introns from nascent eukaryotic gene transcripts in a process called splicing. Small molecules that target different components of the spliceosome represent valuable research tools to investigate this complicated macromolecular machine. However, the current collection of spliceosome inhibitors is very limited. To expand the toolkit we used a high-throughput in vitro splicing assay to screen a collection of pre-fractions of natural compounds derived from marine bacteria for splicing inhibition. Further fractionation of initial hits generated individual peaks of splicing inhibitors that interfere with different stages of spliceosome assembly. With additional characterization of individual peaks, we identified N-palmitoyl-l-leucine as a new splicing inhibitor that blocks a late stage of spliceosome assembly. Structure-activity relationship analysis of the compound revealed that length of carbon chain is important for activity in splicing, as well as for effects on the cytological profile of cells in culture. Together these results demonstrate that our combination of in vitro splicing analysis with complex natural product libraries is a powerful strategy for identifying new small molecule tools with which to probe different aspects of spliceosome assembly and function.
authors.affiliation: From the Department of Molecular, Cell and Developmental Biology, Center for Molecular Biology of RNA, and.
authors.forename: Kerstin A
authors.initials: KA
authors.lastname: Effenberger
authors.affiliation: Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064.
authors.forename: Robert C
authors.initials: RC
authors.lastname: James
authors.affiliation: From the Department of Molecular, Cell and Developmental Biology, Center for Molecular Biology of RNA, and.
authors.forename: Veronica K
authors.initials: VK
authors.lastname: Urabe
authors.affiliation: Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064.
authors.forename: Bailey J
authors.initials: BJ
authors.lastname: Dickey
authors.affiliation: Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064 rliningt@ucsc.edu.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Linington
authors.affiliation: From the Department of Molecular, Cell and Developmental Biology, Center for Molecular Biology of RNA, and mjurica@ucsc.edu.
authors.forename: Melissa S
authors.initials: MS
authors.lastname: Jurica
mesh_terms: D001688:Biological Products / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006367:HeLa Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D007438:Introns; D007930:Leucine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D012326:RNA Splicing / Q000187:drug effects*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D017381:Spliceosomes / Q000187:drug effects* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D001688:Biological Products; C526459:N-palmitoylleucine; D012333:RNA, Messenger; D007930:Leucine
keywords: RNA splicing; drug screening; inhibitor; natural product; spliceosome