Non-cell-autonomous cancer progression from chromosomal instability.

Chromosomal instability (CIN) is a driver of cancer metastasis, yet the extent to which this effect depends on the immune system remains unknown. Using ContactTracing-a newly developed, validated and benchmarked tool to infer the nature and conditional dependence of cell-cell interactions from single-cell transcriptomic data-we show that CIN-induced chronic activation of the cGAS-STING pathway promotes downstream signal re-wiring in cancer cells, leading to a pro-metastatic tumour microenvironment. This re-wiring is manifested by type I interferon tachyphylaxis selectively downstream of STING and a corresponding increase in cancer cell-derived endoplasmic reticulum (ER) stress response.

Miniature type V-F CRISPR-Cas nucleases enable targeted DNA modification in cells.

Class 2 CRISPR systems are exceptionally diverse, nevertheless, all share a single effector protein that contains a conserved RuvC-like nuclease domain. Interestingly, the size of these CRISPR-associated (Cas) nucleases ranges from >1000 amino acids (aa) for Cas9/Cas12a to as small as 400-600 aa for Cas12f. For in vivo genome editing applications, compact RNA-guided nucleases are desirable and would streamline cellular delivery approaches.

Transposon-associated TnpB is a programmable RNA-guided DNA endonuclease.

Transposition has a key role in reshaping genomes of all living organisms. Insertion sequences of IS200/IS605 and IS607 families are among the simplest mobile genetic elements and contain only the genes that are required for their transposition and its regulation. These elements encode tnpA transposase, which is essential for mobilization, and often carry an accessory tnpB gene, which is dispensable for transposition.

PAM recognition by miniature CRISPR-Cas12f nucleases triggers programmable double-stranded DNA target cleavage.

In recent years, CRISPR-associated (Cas) nucleases have revolutionized the genome editing field. Being guided by an RNA to cleave double-stranded (ds) DNA targets near a short sequence termed a protospacer adjacent motif (PAM), Cas9 and Cas12 offer unprecedented flexibility, however, more compact versions would simplify delivery and extend application. Here, we present a collection of 10 exceptionally compact (422-603 amino acids) CRISPR-Cas12f nucleases that recognize and cleave dsDNA in a PAM dependent manner.