Initiation at the third in-frame AUG codon
of open reading frame 3 of the hepatitis E virus is essential for viral infectivity in vivo.
Base-pairing interactions between the Shine-Dalgarno sequence and the anti-Shine-Dalgarno sequence momentarily tether the mRNA to the face of the 30S ribosomal subunit and increase the likelihood that an appropriately spaced AUG codon
will be utilized during translational initiation (reviewe d in 3).
In cases where an upstream AUG codon
is followed by a short open reading frame, the 40 S subunit can reinitiate scanning and initiate translation from a downstream AUG (11).
In estimating our results, we had in mind the first initiation codon, which is thought to have more favorable flanking sequences for initiation of protein synthesis, although use of leaky scanning mechanism could be the reason of initiation at the second AUG codon