Analyzing the 5'-3' Kissing-Loop Interaction Sequence for Cap-Independent Translation Initiation of Blackcurrant Reversion Virus

• Published in: The FASEB journal Vol. 36 Suppl 1
• Main Authors: Zhou, Liheng, Lee, Julie, Baquero-Galvis, Laura D, Filbin, Megan E
• Format: Journal Article
• Language: English
• Published: United States 01.05.2022
• ISSN: 1530-6860
• DOI: 10.1096/fasebj.2022.36.S1.R3201

Translation regulation commonly involves the 5'-m7GpppN cap which binds the initiation factor 4E bound to recruit the other initiation factors and the small ribosomal subunit. Yet some viruses, such as the Blackcurrant Reversion virus (BRV), have no 5'-cap but are still able to translate using alternative mechanisms such as 3' cap independent translation enhancers (3' CITE). The 3' CITEs in BRV's bipartite genome are predicted to work like 4E by recruiting initiation factors and bringing them to the 5' end for initiation of translation though a 5'-3' RNA kissing interaction, called the kissing-loop interaction sequence (KIS). Our goal is to verify whether or not the KIS between the 5' UTR and 3' CITE exists to promote translation initiation. Using site-directed mutagenesis and in vitro transcription, we created a series of KIS mutations (including compensatory mutations). Our preliminary in vitro luciferase translation experiments indicate the putative KIS between the 5' UTR and 3' CITE may not be important for translation initiation, however, we are currently working to verify these results and identify alternative KISs between the 5' and 3' ends. Although many CITEs use 5'-3' RNA kissing interactions to deliver translation machinery to the 5' end of the genome, it is not required for CITE function. The BRV CITE may function through a protein bridge or some other unknown mechanism.