文档介绍：tRNA Synthesis and Secondary article
Regulation Article Contents
. Introduction
Takuya Ueda, University of Tokyo, Tokyo, Japan . Prokaryotic Systems
Kimitsuna Watanabe, University of Tokyo, Tokyo, Japan . Eukaryotic Systems
. Synthesis of Mature tRNA
.
Transfer RNA is primarily synthesized by transcription by RNA polymerase and es Summary
the mature form via several steps: processing, splicing, CCA addition and
posttranscriptional modification. The concentration of individual tRNA molecules is
controlled in order to maintain cellular functions.
Introduction
eukaryotes, chloroplasts, plant mitochondria and in some
The size position of the intracellular transfer RNA bacteria, are also spliced out by a specific endonuclease and
(tRNA) pool is regulated at several stages of RNA the resultant two RNA fragments are joined by RNA
synthesis and degradation to ensure efficient translation ligase. A sequences, which pletely con-
by tRNA molecules. Codons residing in the reading frames served at 3’ termini of all tRNAs known so far, are not
of protein genes encoded on the genomes of individual encoded in tRNA genes in some species and are
anisms are not equally utilized. Such codon posttranscriptionally added by A-adding enzyme.
biases may reflect nucleotide selections resulting from All mature tRNA molecules contain modified nucleotides
directional mutation pressure du