Using nucleolytic toxins as restriction enzymes enables new RNA applications.

Over the past five decades, DNA restriction enzymes have revolutionized biotechnology. While these enzymes are widely used in DNA research and DNA engineering, the emerging field of RNA and mRNA therapeutics requires sequence-specific RNA endoribonucleases. Here, we describe EcoToxN1, a member of the type III toxin-antitoxin family of sequence-specific RNA endoribonucleases, and its use in RNA and mRNA analysis.

Piscine Orthoreovirus (PRV)-3, but Not PRV-2, Cross-Protects against PRV-1 and Heart and Skeletal Muscle Inflammation in Atlantic Salmon.

Heart and skeletal muscle inflammation (HSMI), caused by infection with (PRV-1), is a common disease in farmed Atlantic salmon (). Both an inactivated whole virus vaccine and a DNA vaccine have previously been tested experimentally against HSMI and demonstrated to give partial but not full protection. To understand the mechanisms involved in protection against HSMI and evaluate the potential of live attenuated vaccine strategies, we set up a cross-protection experiment using PRV genotypes not associated with disease development in Atlantic salmon.

Autophagy mediates temporary reprogramming and dedifferentiation in plant somatic cells.

Somatic cells acclimate to changes in the environment by temporary reprogramming. Much has been learned about transcription factors that induce these cell-state switches in both plants and animals, but how cells rapidly modulate their proteome remains elusive. Here, we show rapid induction of autophagy during temporary reprogramming in plants triggered by phytohormones, immune, and danger signals.

Microbial Danger Signals Control Transcriptional Induction of Distinct MHC Class I L Lineage Genes in Atlantic Salmon.

Antigen processing and presentation by major histocompatibility complex (MHC) molecules is a cornerstone in vertebrate immunity. Like mammals, teleosts possess both classical MHC class I and multiple families of divergent MHC class I genes. However, while certain mammalian MHC class I-like molecules have proven to be integral in immune regulation against a broad array of pathogens, the biological relevance of the different MHC class I lineages in fish remains elusive.

Endosomal microautophagy is an integrated part of the autophagic response to amino acid starvation.

Starvation is a fundamental type of stress naturally occurring in biological systems. All organisms have therefore evolved different safeguard mechanisms to cope with deficiencies in various types of nutrients. Cells, from yeast to humans, typically respond to amino acid starvation by initiating degradation of cellular components by inducing autophagy.

Starvation induces rapid degradation of selective autophagy receptors by endosomal microautophagy.

It is not clear to what extent starvation-induced autophagy affects the proteome on a global scale and whether it is selective. In this study, we report based on quantitative proteomics that cells during the first 4 h of acute starvation elicit lysosomal degradation of up to 2-3% of the proteome. The most significant changes are caused by an immediate autophagic response elicited by shortage of amino acids but executed independently of mechanistic target of rapamycin and macroautophagy.

Regulation of selective autophagy: the p62/SQSTM1 paradigm.

In selective autophagy, cytoplasmic components are selected and tagged before being sequestered into an autophagosome by means of selective autophagy receptors such as p62/SQSTM1. In this review, we discuss how selective autophagy is regulated. An important level of regulation is the selection of proteins or organelles for degradation.

Turnip Mosaic Virus Counteracts Selective Autophagy of the Viral Silencing Suppressor HCpro.

Autophagy is a conserved intracellular degradation pathway and has emerged as a key mechanism of antiviral immunity in metazoans, including the selective elimination of viral components. In turn, some animal viruses are able to escape and modulate autophagy for enhanced pathogenicity. Whether host autophagic responses and viral countermeasures play similar roles in plant-virus interactions is not well understood.

Selective autophagy.

During the last decade it has become evident that autophagy is not simply a non-selective bulk degradation pathway for intracellular components. On the contrary, the discovery and characterization of autophagy receptors which target specific cargo for lysosomal degradation by interaction with ATG8 (autophagy-related protein 8)/LC3 (light-chain 3) has accelerated our understanding of selective autophagy. A number of autophagy receptors have been identified which specifically mediate the selective autophagosomal degradation of a variety of cargoes including protein aggregates, signalling complexes, midbody rings, mitochondria and bacterial pathogens.

Plant NBR1 is a selective autophagy substrate and a functional hybrid of the mammalian autophagic adapters NBR1 and p62/SQSTM1.

(Macro)autophagy encompasses both an unselective, bulk degradation of cytoplasmic contents as well as selective autophagy of damaged organelles, intracellular microbes, protein aggregates, cellular structures and specific soluble proteins. Selective autophagy is mediated by autophagic adapters, like p62/SQSTM1 and NBR1. p62 and NBR1 are themselves selective autophagy substrates, but they also act as cargo receptors for degradation of other substrates.