       Document 0754
 DOCN  M9620754
 TI    Analysis of the role of the pseudoknot component in the SRV-1 gag-pro
       ribosomal frameshift signal: loop lengths and stability of the stem
       regions.
 DT    9602
 AU    ten Dam EB; Verlaan PW; Pleij CW; Leiden Institute of Chemistry,
       Gorlaeus Laboratories, Leiden; University, The Netherlands.
 SO    RNA. 1995 Apr;1(2):146-54. Unique Identifier : AIDSLINE MED/96079947
 AB    The simian retrovirus-1 (SRV-1) gag-pro frameshift signal was identified
       in previous work, and the overall structure of the pseudoknot involved
       was confirmed (ten Dam E, Brierley I, Inglis S, Pleij C, 1994, Nucleic
       Acids Res 22:2304-2310). Here we report on the importance of specific
       elements within the pseudoknot. Some mutations in stem S1 that maintain
       base pairing have reduced frameshift efficiencies. This indicates that
       base pairing in itself is not sufficient. In contrast, frameshifting
       correlates qualitatively with the calculated stability of mutations in
       S2. The stems thus play different roles in the frameshift event. The
       nature of the base in L1 has little influence on frameshift efficiency.
       It is however required to bridge S2; deleting it lowers frameshifting
       from 23 to 9%. In L2, frameshift efficiency was not affected in a mutant
       that changed 10 to 12 bases. This makes it unlikely that the primary
       sequence of L2 plays a role in 1 frameshifting, in contrast to
       readthrough in Moloney murine leukemia virus (Wills N, Gesteland R,
       Atkins J, 1994, EMBO J 13:4137-4144). Deletions of 2 and 3 bases gave
       more frameshifting than the wild type, probably reflecting the increased
       stability of the pseudoknot due to a shorter loop L2. Deleting even more
       bases reduces frameshifting compared to wild-type levels. At this point,
       stress will build up in L2, and this will reduce overall pseudoknot
       stability.
 DE    Animal  Base Sequence  Frameshift Mutation  *Frameshifting, Ribosomal
       Genes, gag  Molecular Sequence Data  Nucleic Acid Conformation
       Retroviruses Type D, Simian/*GENETICS  RNA, Double-Stranded/CHEMISTRY
       RNA, Viral/*CHEMISTRY  Structure-Activity Relationship  JOURNAL ARTICLE

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

