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Evolution of a Transfer RNA Gene Through a Point Mutation in the Anticodon

Saks, Margaret E. and Sampson, Jeffrey R. and Abelson, John (1998) Evolution of a Transfer RNA Gene Through a Point Mutation in the Anticodon. Science, 279 (5357). pp. 1665-1670. ISSN 0036-8075. doi:10.1126/science.279.5357.1665.

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The transfer RNA (tRNA) multigene family comprises 20 amino acid–accepting groups, many of which contain isoacceptors. The addition of isoacceptors to the tRNA repertoire was critical to establishing the genetic code, yet the origin of isoacceptors remains largely unexplored. A model of tRNA evolution, termed “tRNA gene recruitment,” was formulated. It proposes that a tRNA gene can be recruited from one isoaccepting group to another by a point mutation that concurrently changes tRNA amino acid identity and messenger RNA coupling capacity. A test of the model showed that an Escherichia coli strain, in which the essential tRNA_(UGU)^(Thr) gene was inactivated, was rendered viable when a tRNA^(Arg) with a point mutation that changed its anticodon from UCU to UGU (threonine) was expressed. Insertion of threonine at threonine codons by the “recruited” tRNA^(Arg) was corroborated by in vitro aminoacylation assays showing that its specificity had been changed from arginine to threonine. Therefore, the recruitment model may account for the evolution of some tRNA genes.

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Additional Information:© 1999 American Association for the Advancement of Science. Received 3 July 1997; accepted 23 January 1998. We thank S. R. Kushner, V. Maples, and H. Shizuya for providing E. coli strains and for guidance in constructing the knockout strain, and A. Zera, F. Gould, and M. Lynch for thoughtful comments. Supported by NIH grant GM 48560.
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NIHGM 48560
Issue or Number:5357
Record Number:CaltechAUTHORS:20141125-094056321
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Official Citation:Evolution of a Transfer RNA Gene Through a Point Mutation in the Anticodon Margaret E. Saks, Jeffrey R. Sampson, and John Abelson Science 13 March 1998: 279 (5357), 1665-1670. [DOI:10.1126/science.279.5357.1665]
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52131
Deposited By: Tony Diaz
Deposited On:25 Nov 2014 20:29
Last Modified:10 Nov 2021 19:21

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