Anna Chechenina

Abstract Viruses compete with each other for limited cellular resources, and some viruses deliver defense mechanisms that protect the host from competing genetic parasites. PARIS is a defense system, often encoded in viral genomes, that is composed of a 53 kDa ABC ATPase (AriA) and a 35 kDa TOPRIM nuclease (AriB). Here we show that AriA and AriB assemble into a 425 kDa supramolecular immune complex. We use cryo-EM to determine the structure of this complex which explains how six molecules of AriA assemble into a propeller-shaped scaffold that coordinates three subunits of AriB. ATP-dependent detection of foreign proteins triggers the release of AriB, which assembles into a homodimeric nuclease that blocks infection by cleaving the host tRNA Lys . Phage T5 subverts PARIS immunity through expression of a tRNA Lys variant that prevents PARIS-mediated cleavage, and thereby restores viral infection. Collectively, these data explain how AriA functions as an ATP-dependent sensor that detects viral proteins and activates the AriB toxin. PARIS is one of an emerging set of immune systems that form macromolecular complexes for the recognition of foreign proteins, rather than foreign nucleic acids.

Mechanical forces arising in developing embryos are able to spread over considerable distances in embryos and affect gene expression. The study of mechano-dependent transcription is one of the topical issues of modern developmental biology. One of the approaches to solving this problem is the use of low-molecular-weight myosin inhibitors. In this paper, we studied by RT-PCR the effect of four myosin inhibitors—blebbistatin, S-nitroblebbistatin, ML-9 and 2,3-butanedione monoxime—on the expression of eight mechano-dependent genes in early embryos of the clawed frog. When exposed to myosin inhibitors, we observed a change in the expression level of four mechano-dependent genes, namely gsc, myh6, Xbra, and xmc. These results indicate that mechanical forces can play a role in the anterio-posterior patterning of the embryo by regulating the expression of the corresponding genes.

Key Points High dietary fiber intake increases gut microbiome diversity and specific fibers link to MRD negativity in NDMM patients. Microbial signatures and butyrate-producing taxa segregate auto-HCT response and may link fiber intake to immune-modulating effects.

final concentration) (6-carboxyfluorescein)", the text "2 nM FAM (final concentration)" appeared initially as "20 M FAM".The affiliation for Svetlana Belukhina, Mikhail Skutel, Anna Chechenina and Artem Isaev has also been updated.