Overall Rating (5/5)

Impact (5/5) This paper describes studies aimed at solving the mystery of the role of EBER1 in Epstein-Barr virus (EBV) infections. As noted by the authors, EBV has been studied extensively and the importance of EBER1 has been known for over 40 years but how it aids in EBV infections has remained elusive due to the fact that it has been impervious to attempts at knockdown using conventional methods to date. Now, using CRISPR, the authors have been able to knock down EBER1 by over 90% and see the effects. In their interesting findings they see that unlike most RNA modulators, EBER1 does not work directly on the genome but instead, acts as a translation modifier by inhibiting the ribosomal protein L22 which then allows for the upregulation of its paralog, L22L1. The effect of this on cellular function is to increase oxidative phosphorylation, an event which supports cellular growth and transformation. This finding has high impact and with further work can lead to finding targets to limit the spread of cancers that are EBV based. One suggestion is to change the title to “Epstein-Barr virus non-coding RNA EBER1 promotes the expression of the ribosomal protein paralog L22L1 to boost oxidative phosphorylation” to increase search engine hits.

Methods (4/5) The authors used standard cell culture methods with the use of CRISPR to knock down EBER1 in EBV infected BJAB-B1 cells. BJAB cells are an EBV negative tumor cell line often used in oncology studies. For these studies they infected these cells with EBV so as to have controls and steady state EBV levels. Immunoblotting was used to confirm increases in L22L1.The methods were all cell based and appropriate. Next steps, although not for this particular study, would be to produce a mouse model of EBER1 conditional knockdown and see if introduction of EBV led to EBV based cancers or other diseases.

Results (5/5) The results clearly show that loss of EBER1 causes an increase in L22L1 within ribosomes. Overexpression of L22L1 in ribosomes led to the expression of mRNAs associated with oxidative phosphorylation. Examination of ribosomal subunits in the EBER1 knockdown cells confirmed that loss of EBER1 led to a similar pattern of mRNAs expression associated with oxidative phosphorylation. Interestingly, if L22L1 was knocked down in these cells, colony formation was inhibited suggesting that a role for oxidative phosphorylation in the formation of growth and potentially transformation.

Discussion (5/5) This paper gives an intriguing look into the pathway by which EBV can lead to cancer formation, something which has eluded researchers for decades. Thus, this study has the potential to be very high impact. The study identifies a key step by which EBER1, a known protein involved in EBV function, leads to cellular growth by activating L22L1 which is a paralog to the ribosomal protein L22. Activation of L22L1 stimulated oxidative phosphorylation pathways that are normally quiescent which in turn allows for cellular growth. There are still many holes in the story, but this paper plugs a big one. It would be nice to see the next steps taken in determining how these particular oxidative phosphorylation pathways stimulate cancer growth. Also, as noted above, moving this into a mouse model would be a great step, although not needed for the publication of this particular article.

Reviewer Information The reviewer (Dr. Heather Duffy) is the Chair of Biotechnology at the Franklin Cummings Technical Institute. Her PhD is in neuroscience, but her work is as a protein biochemist working on inflammation, signal transduction, and cell-cell communication. She has worked in both industry and academia for over 20 years.

Dr. Heather Duffy on ResearchHub: https://www.researchhub.com/user/1790894/overview

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