internal ribosome entry site (IRES)

Introduction

• distinct regions of viral mRNA able to attract the eukaryotic ribosome &, thus, allow translation initiation
  • generally located in the 5'UTR of RNA viruses

Function

• allows for translation initiation in the middle of mRNA
• used by viruses as a means to ensure that viral translation is active during periods of time when host translation is inhibited

More general terms

• RNA motif