E. Goldman et al., CONSECUTIVE LOW-USAGE LEUCINE CODONS BLOCK TRANSLATION ONLY WHEN NEARTHE 5' END OF A MESSAGE IN ESCHERICHIA-COLI, Journal of Molecular Biology, 245(5), 1995, pp. 467-473
Insertion of nine consecutive low-usage CUA leucine codons after codon
13 of a 313-codon test mRNA strongly inhibited its translation withou
t apparent effect on translation of other mRNAs containing CUA codons.
In contrast, nine consecutive high-usage CUG leucine codons at the sa
me position had no apparent effect, and neither low- nor high-usage co
dons affected translation when inserted after codon 223 or 307. Additi
onal experiments indicated that the strong positional effect of the lo
w-usage codons could not be accounted for by differences in stability
of the mRNAs or in stringency of selection of the correct tRNA. The po
sitional effect could be explained if translation complexes are less s
table near the beginning of a message: slow translation through low-us
age codons early in the message may allow most translation complexes t
o dissociate before they read through.