title: Nonsense mutations inhibit RNA splicing in a cell-free system: recognition of mutant codon is independent of protein synthesis.
abstract: Mutations resulting in premature termination codons reduce the corresponding mRNA levels. We describe a cell-free system in which depletion of the mutant immunoglobulin kappa mRNA pool correlates with inefficient splicing and not with RNA decay. Splicing deficiency does not depend on the sequence surrounding the in-frame nonsense codon and can be partially corrected by mutating the methionine initiation codon. Despite the apparent link between translation and low mutant mRNA levels, inefficient splicing is not dependent on protein synthesis. Abnormal splicing of mutant immunoglobulin RNA is observed with B-cell but not with HeLa or T-cell extracts. A nonsense mutant beta-globin RNA is normally spliced by B-cell extract. We propose that the phenomenon exhibits tissue and gene specificity.
authors.affiliation: Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Aoufouchi
authors.forename: J
authors.initials: J
authors.lastname: Yélamos
authors.forename: C
authors.initials: C
authors.lastname: Milstein
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D001483:Base Sequence; D002457:Cell Extracts / Q000502:physiology; D002467:Cell Nucleus / Q000235:genetics; D002474:Cell-Free System; D018389:Codon, Nonsense / Q000235:genetics* / Q000494:pharmacology; D006367:HeLa Cells / Q000502:physiology; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000235:genetics; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics; D014176:Protein Biosynthesis; D012322:RNA Precursors / Q000378:metabolism; D012326:RNA Splicing / Q000187:drug effects / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D013601:T-Lymphocytes / Q000502:physiology; D014407:Tumor Cells, Cultured
chemical_list: D002457:Cell Extracts; D018389:Codon, Nonsense; D007147:Immunoglobulin Light Chains; D012322:RNA Precursors; D012333:RNA, Messenger