RNA binding of Hfq monomers promotes RelA-mediated hexamerization in a limiting Hfq environment

Pallabi Basu, Maya Elgrably-Weiss, Fouad Hassouna, Manoj Kumar, Reuven Wiener, Shoshy Altuvia*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The RNA chaperone Hfq, acting as a hexamer, is a known mediator of post-transcriptional regulation, expediting basepairing between small RNAs (sRNAs) and their target mRNAs. However, the intricate details associated with Hfq-RNA biogenesis are still unclear. Previously, we reported that the stringent response regulator, RelA, is a functional partner of Hfq that facilitates Hfq-mediated sRNA–mRNA regulation in vivo and induces Hfq hexamerization in vitro. Here we show that RelA-mediated Hfq hexamerization requires an initial binding of RNA, preferably sRNA to Hfq monomers. By interacting with a Shine–Dalgarno-like sequence (GGAG) in the sRNA, RelA stabilizes the initially unstable complex of RNA bound-Hfq monomer, enabling the attachment of more Hfq subunits to form a functional hexamer. Overall, our study showing that RNA binding to Hfq monomers is at the heart of RelA-mediated Hfq hexamerization, challenges the previous concept that only Hfq hexamers can bind RNA.

Original languageAmerican English
Article number2249
JournalNature Communications
Issue number1
StatePublished - 1 Dec 2021

Bibliographical note

Funding Information:
We are grateful to Sarah Woodson for her advice throughout the study. We appreciate the excellent assistance in strain and plasmid construction by Tal Hershko-Shalev and Noa Nur. This work was supported by: the Israel Science Foundation founded by The Israel Academy of Sciences and Humanities (138/18), and the Deutsch-lsraelische Pro-jektkooperation (AM 441/1-1 SO 568/1-1).

Publisher Copyright:
© 2021, The Author(s).


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