title: A subtle alternative splicing event gives rise to a widely expressed human RNase k isoform.
abstract: Subtle alternative splicing leads to the formation of RNA variants lacking or including a small number of nucleotides. To date, the impact of subtle alternative splicing phenomena on protein biosynthesis has been studied in frame-preserving incidents. On the contrary, mRNA isoforms derived from frame-shifting events were poorly studied and generally characterized as non-coding. This work provides evidence for a frame-shifting subtle alternative splicing event which results in the production of a novel protein isoform. We applied a combined molecular approach for the cloning and expression analysis of a human RNase κ transcript (RNase κ-02) which lacks four consecutive bases compared to the previously isolated RNase κ isoform. RNase κ-02 mRNA is expressed in all human cell lines tested end encodes the synthesis of a 134-amino-acid protein by utilizing an alternative initiation codon. The expression of RNase κ-02 in the cytoplasm of human cells was verified by Western blot and immunofluorescence analysis using a specific polyclonal antibody developed on the basis of the amino-acid sequence difference between the two protein isoforms. The results presented here show that subtle changes during mRNA splicing can lead to the expression of significantly altered protein isoforms.
authors.affiliation: University of Athens, Faculty of Biology, Department of Biochemistry and Molecular Biology, Athens, Greece.
authors.forename: Evangelos D
authors.initials: ED
authors.lastname: Karousis
authors.affiliation: University of Athens, Faculty of Biology, Department of Biochemistry and Molecular Biology, Athens, Greece.
authors.forename: Diamantis C
authors.initials: DC
authors.lastname: Sideris
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004722:Endoribonucleases / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D004722:Endoribonucleases; C525216:RNase kappa, human