Biology subjects

Schlegel, T.

Publications and source records attributed to Schlegel, T..

3 recordsLinked to original sources

bioRxiv2025

Loss of Vertically-Inherited Totiviruses and Toxin-Encoding Satellites in Killer Yeast Evidences Intracellular Conflict in Natural Populations

Saccharomyces cerevisiae is occasionally infected by totiviruses and their toxin-encoding satellites. Totiviruses and their satellites coexist but with an asymmetric dependence on the totivirus for maintenance inside the host cell. Satellites provide their yeast hosts with inhibitory toxins and the necessary self-immunity; loss of the satellite equates to loss of immunity. Because mycoviruses lack known extracellular stages, and sex is considered rare, mycoviruses are assumed to be transmitted vertically, implying infection states should correlate with host genotypes. However, totivirus-satellite coinfections are rarely examined in natural populations, leaving their associations with host genotypes poorly understood. We screened a multiyear population of S. cerevisiae isolates from New Zealand to examine the stability of host-virus associations over time, both within and across genotypes. While 55% of wild isolates harbored infections, only 37% of these included toxin-encoding satellites. Genotypes that persisted across years typically maintained consistent infection states. However, we observed stepwise transitions including acquisitions of totiviruses and satellites. Genotypes clustered strongly by infection state, supporting vertical transmission while suggesting that outcrossing is not responsible for the mycovirus acquisitions. Despite infection changes, genotype clustering by infection state remained intact, suggesting transitions are transient and that host genotypes may have optimal totivirus-satellite infection states.

evolutionary biology↗

bioRxiv2024

Pangenomic context reveals the extent of intraspecific plant NLR evolution

Nucleotide-binding leucine-rich repeat (NLR) proteins are a major component of the plant immune system, which directly or indirectly detect molecular signals of pathogen invasion. Despite their critical role, the processes by which NLR genes diversify remain poorly characterised due to the extraordinary sequence, structural, and regulatory variability of NLRs, even among closely related individuals. To understand the evolution of NLR diversity in Arabidopsis thaliana, we leverage graph-based methods to define pangenomic NLR neighbourhoods in 17 genetically diverse genomes. We integrate full-length transcript and transposable element information to exhaustively annotate all intact and degraded NLRs, enabling exploration of the processes that underpin the birth, death and maintenance of NLR diversity within a species. Our main finding is that many uncorrelated mutational processes create NLR diversity, and that there is no single metric that captures on its own the true extent of NLR structural and sequence variation. This immense diversity in plant immune system diversification allows populations to survive the constant onslaught of pathogens, not unlike vertebrate adaptive immunity, where variation is also generated by a variety of complementary mechanisms, albeit at the level of individuals.

plant biology↗

bioRxiv2023

CLUH maintains functional mitochondria and translation in motoneuronal axons and prevents peripheral neuropathy

Transport and local translation of mRNAs in distal axonal compartments are essential for neuronal viability. Local synthesis of nuclear-encoded mitochondrial proteins protects mitochondria from damage during their long journey along the axon, however the regulatory factors involved are largely unknown. Here, we show that CLUH, a cytosolic protein that binds mRNAs encoding mitochondrial proteins, is essential for preventing axonal degeneration of spinal motoneurons and maintaining motor behavior in the mouse. We demonstrate that CLUH is enriched in the growth cone of developing spinal motoneurons and is required for their growth. The absence of CLUH affects the abundance of target mRNAs and the corresponding mitochondrial proteins more prominently in axons, leading to ATP deficits specifically in the growth cone. CLUH binds ribosomal subunits, translation initiation and ribosome recycling components, and preserves axonal translation. Overexpression of the ribosome recycling factor ABCE1 rescues the growth cone and translation defects in CLUH-deficient motoneurons. In conclusion, we demonstrate a role for CLUH in mitochondrial quality control and translational regulation in axons, which are essential for their development and long-term integrity and function.

cell biology↗