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bioRxiv · 10.1101/2025.10.15.682605

The GT1 domain of RNase J ensures RNA quality control through dsRNA binding in Arabidopsis plastids

Baudry, K.·Skiada, S.·Burstein, C.·Liveanu, V.·Liehrmann, A.·Ceminsky, M.·Kleifeld, O.·Delannoy, E.·Launay-Avon, A.·Castandet, B.·Schuster, G.·Stern, D.
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Abstract

RNase J is a ribonuclease found in bacteria, archaea, and plant chloroplasts, and plays diverse roles in RNA maturation and stability. Chloroplast RNase J is encoded by the nuclear RNJ locus and is essential for embryo maturation. Arabidopsis or tobacco plants depleted for RNase J accumulate massive amounts of double-stranded RNA, which interferes with translation and causes chlorosis. Land plant RNase J uniquely contains a C-terminal GT1 domain, a DNA- binding motif found in transcription factors. Here, we have used complementation of an Arabidopsis rnj mutant with versions of RNase J with a mutated or deleted GT1 domain to investigate its role in RNase J function. We show that in vitro, the recombinant GT1 domain binds both double-stranded RNA and DNA, but not single-stranded nucleic acids, with no sequence specificity. Furthermore, while RNase J lacking GT1 binding complements the rnj mutant, these plants accumulate high levels of dsRNA as detected by immunolocalization and RNA-Seq. GT1 mutations also change RNase J solubility in vivo, suggesting that the GT1 domain is involved in localization within the plastid. Taken together, our results suggest that the GT1 domain plays a key role in dsRNA removal through localizing the enzyme and/or selectively binding the dsRNA substrate. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/682605v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@e5642borg.highwire.dtl.DTLVardef@136456org.highwire.dtl.DTLVardef@1205466org.highwire.dtl.DTLVardef@184f72b_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Baudry, K., Skiada, S., Burstein, C., Liveanu, V., Liehrmann, A., Ceminsky, M., Kleifeld, O., Delannoy, E., Launay-Avon, A., Castandet, B., Schuster, G., Stern, D.. 2025-10-15. The GT1 domain of RNase J ensures RNA quality control through dsRNA binding in Arabidopsis plastids. https://doi.org/10.1101/2025.10.15.682605

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