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bioRxiv · 10.1101/2020.04.18.045682

Internal translation of large subunit transcripts drives small subunit synthesis in type I CRISPR-Cas interference complexes

McBride, T. M.·Schwartz, E. A.·Kumar, A.·Taylor, D. W.·Fineran, P. C.·Fagerlund, R. D.
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Abstract

CRISPR-Cas adaptive immune systems provide prokaryotes with defense against viruses by degradation of specific invading nucleic acids. We investigated the previously uncharacterized type I-D interference complex from Synechocystis and revealed it is a genetic and structural hybrid with similarity to both type I and III systems. Surprisingly, formation of the functional complex required internal in-frame translation of small subunits from within the large subunit gene. We further show that internal translation to generate small subunits is widespread across diverse type I-D, I-B and I-C systems, which account for roughly one quarter of CRISPR-Cas systems. Our work reveals the unexpected expansion of protein coding potential from within single cas genes, which has important implications for understanding CRISPR-Cas function and evolution. One Sentence SummaryInternal translation of large subunit transcripts drives small subunit synthesis in diverse type I CRISPR-Cas interference complexes

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McBride, T. M., Schwartz, E. A., Kumar, A., Taylor, D. W., Fineran, P. C., Fagerlund, R. D.. 2020-04-18. Internal translation of large subunit transcripts drives small subunit synthesis in type I CRISPR-Cas interference complexes. https://doi.org/10.1101/2020.04.18.045682

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