Translation initiation in eukaryotes begins at AUG codon that occurs in favorable context in majority of the cases. The nucleotides at positions -3 and/or +4 flanking AUG codon are shown to contribute significantly in modulating the efficiency of translation initiation. The preferred nucleotides at these positions are a purine base at position -3 and a guanine base at position +4. Here the context is referred as 'Weak' if a pyrimidine base is observed at position -3 AND A/T/C is observed at position +4 around the AUG codon.

We found human mRNA sequences in RefSeq database that begin translation at AUG codons that are in weak context. A neural network has been developed (S. Tikole and R. Sankararamakrishnan, Biochem. Biophys. Res. Commn. 369, 1166-1168, 2008) to predict the translation initiation site of human mRNA sequences that are likely to have AUG start codons in weak context. The dataset used to develop this method is located here. The program is available in the form of web server.