CONTEXT SEQUENCES OF TRANSLATION INITIATION CODON IN PLANTS

In this survey of 5074 plant genes for their AUG context sequences, pu rines are present at the -3 and +4 positions in about 80% of the seque nces. Although this observation is similar to the vertebrate consensus sequence, the number of plant mRNAs with purines at the -3 position i s lower and at the +4 position is higher than reported for vertebrate mRNAs. Higher plants have an AC-rich consensus sequence, caA(A/C)aAUGG Cg as a context of translation initiator codon. Between the two major groups of angiosperms, the context of the AUG codon in dicot mRNAs is aaA(A/C)aAUGGCu which is similar to the higher-plant consensus but mon ocot mRNAs have c(a/c)(A/G)(A/C)cAUGGCG as a consensus which exhibits an overall similarity with the vertebrate consensus. The experimental evidence regarding the importance of the AUG context in plants is disc ussed.