cis Acting RNA sequences control the gag-pol translation readthrough in murine leukemia virus.
The pol gene of the Moloney murine leukemia virus (M-MuLV) is expressed as a Gag-Pol fusion protein through an in-frame suppression of the UAG termination codon located between the two genes. The role of nucleotide context in suppression was investigated, in a rabbit reticulocyte lysate translation system, using site-directed mutagenesis. The results indicate that the translational readthrough is mediated by at least 50 bases long RNA sequence located 3' to the gag UAG termination codon. Within this sequence a short purine-rich sequence adjacent to the amber codon, highly conserved among different retroviruses, appears essential for M-MuLV suppression. Two alternative putative stem and loop like RNA structures can be drawn at the gag-pol junction, one abutting the gag UAG codon, and the second downstream to it. None of these structures appears to be important to the suppression process.
Honigman
A
A
Department of Molecular Genetics and Virology, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Wolf
D
D
Yaish
S
S
Falk
H
H
Panet
A
A
D000818:Animals; D001483:Base Sequence; D003062:Codon; D015685:Fusion Proteins, gag-pol / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D015750:Genes, gag; D015751:Genes, pol; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000737:chemistry*; D011817:Rabbits; D012045:Regulatory Sequences, Nucleic Acid; D012156:Reticulocytes / Q000378:metabolism; D013489:Suppression, Genetic; D013728:Terminator Regions, Genetic
D003062:Codon; D015685:Fusion Proteins, gag-pol; D012367:RNA, Viral