RRC ID 11282
著者 Kanamori Y, Hayakawa Y, Matsumoto H, Yasukochi Y, Shimura S, Nakahara Y, Kiuchi M, Kamimura M.
タイトル A eukaryotic (insect) tricistronic mRNA encodes three proteins selected by context-dependent scanning.
ジャーナル J Biol Chem
Abstract Eukaryotic mRNAs are generally considered monocistronic and encode only one protein. Although dicistronic mRNAs encoding two proteins were found in fungi, plants, and animals, polycistronic mRNAs encoding more than two proteins have remained elusive so far in any eukaryote. Here we demonstrate that a single mRNA from silkworm encodes the precursor of an insect cytokine paralytic peptide (PP) and two new cytokine precursor-like proteins, uENF1 and uENF2. RT-PCR analysis showed that this mRNA is widely conserved in moths. Western blot analyses and reporter assays using its modified mRNAs, created by replacing each one of the three ORFs with the firefly luciferase ORF, showed that all three proteins were translated from this mRNA in cell lines, larval tissues, and cell-free systems. Insertion experiments using the Renilla luciferase ORF or a stem loop ruled out the possible involvement of internal ribosome entry site in the three protein translation. On the other hand, systematic mutation analysis of the translation initiation sequence of the 5'-proximal uENF1 ORF suggested that the context-dependent leaky-scanning mechanism is involved in translation of the downstream uENF2 and PP ORFs. In vitro, a synthetic peptide corresponding to the putative mature form of uENF1 stimulated spreading of hemocytes as did the synthetic PP, whereas that of uENF2 antagonized the stimulating activities of PP and the uENF1 peptide, suggesting that the three proteins control cellular immunity interactively. Thus, eukaryotes have a cellular tricistronic mRNA that encodes three functionally related proteins as in an operon.
巻・号 285(47)
ページ 36933-44
公開日 2010-11-19
DOI 10.1074/jbc.M110.180398
PII S0021-9258(20)46842-5
PMID 20829361
PMC PMC2978622
MeSH Amino Acid Sequence Animals Blotting, Northern Blotting, Western Bombyx Cloning, Molecular Codon, Initiator / genetics Codon, Initiator / metabolism* Cytokines / genetics* Cytokines / metabolism Gene Expression Regulation, Developmental Insect Proteins / genetics* Insect Proteins / metabolism Larva / cytology Larva / genetics Larva / metabolism Luciferases / metabolism Molecular Sequence Data Neuropeptides / genetics* Open Reading Frames / genetics* Peptide Chain Initiation, Translational* Peptide Fragments / chemical synthesis Peptide Fragments / metabolism Protein Biosynthesis RNA, Messenger / genetics* Reverse Transcriptase Polymerase Chain Reaction Ribosomes / genetics* Sequence Homology, Amino Acid Transcription, Genetic
IF 4.238
引用数 20
WOS 分野 BIOCHEMISTRY & MOLECULAR BIOLOGY
リソース情報
カイコ Samia cynthia pryeri