The completed sequence of lymphocytic choriomeningitis virus reveals a unique RNA structure and a gene for a zinc finger protein.
The arenavirus, lymphocytic choriomeningitis virus (LCMV) has a single-stranded RNA genome composed of a large (L) and a small (S) RNA segment. The completed sequence of LCMV, presented here, reveals a formerly unknown gene (Z) on the L genomic segment. This gene is encoded in the positive or message-sense of the viral genomic RNA, whereas the adjacent gene (L) is in the genome-complementary, or negative sense. The ambisense polarity of the genes on the L RNA reiterates the polarity of genes on the small (S) genomic segment. The Z gene encodes a 10-kDa protein containing a single zinc-finger sequence (Cys2His2). A small RNA representing the message sense of the Z gene is found in infected cells and within virions. In contrast to the known LCMV proteins having structural or enzymatic functions, the predicted Z gene product is most likely to be an RNA-binding protein with a regulatory role. The encapsidation of a message sense Z RNA suggests a role for this gene immediately following virus penetration. The L/Z intergenic region is rich in cytidylic acid (C) and presents an unusual RNA structure. All cDNA clones of the intergenic region differ from each other within a certain poly(C) stretch and lack a 30-base region present in the direct RNA sequence. Finally, the completed sequence establishes that the L RNA 5' end is complementary to its 3' end. The L RNA termini, similar to the S RNA termini, have a small but potentially important asymmetry of sequence. LCMV is the first arenavirus to be completely sequenced.
Salvato
M S
MS
Scripps Clinic and Research Foundation, Department of Immunology, La Jolla, California 92037.
Shimomaye
E M
EM
D000595:Amino Acid Sequence; D001345:Autoradiography; D001483:Base Sequence; D015152:Blotting, Northern; D004268:DNA-Binding Proteins / Q000235:genetics*; D005784:Gene Amplification; D015967:Gene Expression Regulation, Viral; D008217:Lymphocytic choriomeningitis virus / Q000235:genetics*; D008667:Metalloproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000235:genetics*; D012984:Software; D013696:Temperature; D013698:Templates, Genetic; D014158:Transcription, Genetic; D015032:Zinc / Q000378:metabolism*
D004268:DNA-Binding Proteins; D008667:Metalloproteins; D012367:RNA, Viral; D015032:Zinc