Document 3165
 DOCN  M94A3165
 TI    Splicing signals are required for the expression of unspliced
       Gag-containing message of moloney murine leukemia virus.
 DT    9412
 AU    Odawara T; Ohshima M; Matano T; Iwamoto A; Yoshikura H; Faculty of
       Medicine, University of Tokyo, Japan.
 SO    Int Conf AIDS. 1994 Aug 7-12;10(1):138 (abstract no. PA0173). Unique
       Identifier : AIDSLINE ICA10/94369410
 AB    OBJECTIVE: All the retroviruses express both unspliced and spliced
       messages simultaneously. However, little is known about the control of
       the production of the unspliced message under the presence of splicing.
       We studied the role of splicing signals on the expression of a
       retroviral unspliced message. METHODS: A Moloney murine leukemia virus
       (MLV)-derived construct, pG3.6, containing gag as a sole coding region
       expressed only small amounts of Gag protein owing to a low message
       level. The expression of Gag was restored by the insertion of 2.8k bp
       int-env fragment downstream of gag in pG3.6 (pGE6.4). We determined the
       sequence in the 2.8k bp fragment required for the expression of the
       unspliced message encoding gag. RESULTS: Inversion or deletion of 441 bp
       sequence containing a splice acceptor signal in the 2.8k bp int-env
       fragment inserted in the downstream of gag abolished the ability of
       increasing the gag message, and insertion of the 441 bp alone in the
       downstream of gag restored the expression level to that of pGE6.4.
       Comparison of nuclear and cytoplasmic RNA levels of pG3.6 with those of
       pGE6.4 indicated that the nuclear-cytoplasmic transport of pG3.6 message
       was impaired. DISCUSSION AND CONCLUSIONS: For the expression of the
       unspliced message encoding gag, MLV genome should be equipped with the
       441 bp sequence containing the splice acceptor signal. If the gag gene
       of pG3.6 or pGE6.4 was replaced with a neomycin resistance gene, the
       expression level was the same for the two constructs. Gag sequence may
       contain an inhibitory signal on the expression of RNA lacking the splice
       signal.
 DE    Animal  Gene Expression  Gene Products, gag/*BIOSYNTHESIS  Genes, env
       *Genes, gag  Genome, Viral  Moloney Leukemia Virus/*GENETICS/METABOLISM
       Mutagenesis, Insertional  RNA Splicing  RNA,
       Messenger/BIOSYNTHESIS/METABOLISM  RNA, Viral/BIOSYNTHESIS/METABOLISM
       Signal Peptides/METABOLISM  MEETING ABSTRACT

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).