Torsional restraint: a new twist on frameshifting pseudoknots.
mRNA pseudoknots have a stimulatory function in programmed -1 ribosomal frameshifting (-1 PRF). Though we previously presented a model for how mRNA pseudoknots might activate the mechanism for -1 PRF, it did not address the question of the role that they may play in positioning the mRNA relative to the ribosome in this process [E. P. Plant, K. L. M. Jacobs, J. W. Harger, A. Meskauskas, J. L. Jacobs, J. L. Baxter, A. N. Petrov and J. D. Dinman (2003) RNA, 9, 168-174]. A separate 'torsional restraint' model suggests that mRNA pseudoknots act to increase the fraction of ribosomes directed to pause with the upstream heptameric slippery site positioned at the ribosome's A- and P-decoding sites [J. D. Dinman (1995) Yeast, 11, 1115-1127]. Here, experiments using a series of 'pseudo-pseudoknots' having different degrees of rotational freedom were used to test this model. The results of this study support the mechanistic hypothesis that -1 ribosomal frameshifting is enhanced by torsional resistance of the mRNA pseudoknot.
Plant
Ewan P
EP
Department of Cell Biology and Molecular Genetics Microbiology Building Room 2135 University of Maryland College Park, MD 20742, USA.
Dinman
Jonathan D
JD
D001483:Base Sequence; D018965:Frameshifting, Ribosomal; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry* / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D012399:Rotation
D012333:RNA, Messenger