Dv. Lavrov et al., A novel type of RNA editing occurs in the mitochondrial tRNAs of the centipede Lithobius forficatus, P NAS US, 97(25), 2000, pp. 13738-13742
Citations number
31
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
We determined the complete mtDNA sequence of the centipede Lithobius forfic
atus and found that only one of the 22 inferred tRNA genes encodes a fully
paired aminoacyl acceptor stem. The other 21 genes encode tRNAs with up to
five mismatches in these stems, and some of these overlap extensively with
the downstream genes. Because a well-paired acceptor stem is required for p
roper tRNA functioning, RNA editing in the products of these genes was susp
ected. We investigated this hypothesis by studying cDNA sequences from eigh
t tRNAs and found the editing of up to 5 nt at their 3' ends. This editing
appears to occur by a novel mechanism with the 5' end of the acceptor stem
being used as a template for the de novo synthesis of the 3' end, presumabl
y by an RNA-dependent RNA polymerase. in addition, unusual secondary struct
ures for several tRNAs were found, including those lacking a T PsiC (T) or
a dihydrouridine (D) arm, and having an unusual number of base pairs in the
acceptor or anticodon stems.