Biology subjects

Rödelsperger, C.

Publications and source records attributed to Rödelsperger, C..

5 recordsLinked to original sources

bioRxiv2026

Plasticity in nonsense-mediated decay and translation initiation regulate polyphenism

Developmental plasticity is increasingly recognised as facilitator of evolutionary novelty. However, how plasticity itself evolves and how variation in plastic trait expression is structured in populations remain unknown1,2. The predatory nematode Pristionchus pacificus exhibits mouth-form plasticity with underlying molecular mechanisms being increasingly identified3. We investigate the temporal scale of natural variation of mouth-form plasticity. An 11-year survey characterised Adoretus beetle-derived isolates from Colorado, La Reunion Island and revealed a gradual shift in mouth-form preference. Quantitative trait locus mapping of mouth-form preferences identified a single peak harbouring the developmental switch gene eud-1. Through CRISPR-engineering and biochemical assays, we show that plasticity in nonsense-mediated decay coupled with alternative start codon selection resulting in different N-terminal proteoforms of EUD-1 are associated with natural variation of mouth-form preference. This work provides molecular explanations for variation in plastic trait expression and links nonsense variants in the major developmental switch locus to ecological and evolutionary processes.

evolutionary biology↗

bioRxiv2020

Tissue-specific safety mechanism results in opposite protein aggregation patterns during aging

During aging, proteostasis capacity declines and aggregation-prone proteins become instable, accumulating in protein aggregates both inside and outside cells. Both in disease and during aging, proteins selectively aggregate in certain tissues and not others. Yet, tissue-specific regulation of protein aggregation remains poorly understood. Surprisingly, we found that the inhibition of three core protein quality control systems, i.e. chaperones, proteasome and macroautophagy, leads to lower levels of age-dependent protein aggregation in C. elegans pharyngeal muscles, but higher levels in body-wall muscles. We describe a novel safety mechanism called SAPA that selectively targets newly synthesized aggregation-prone proteins to suppress aggregation and proteotoxicity. vha-12 and scav-3 mutants reveal that SAPA relies on macroautophagy-independent lysosomal degradation. Furthermore, SAPA involves several previously uncharacterized components of the intracellular pathogen response. We propose that SAPA represents an anti-aggregation machinery targeting aggregation-prone proteins for lysosomal degradation.

cell biology↗

bioRxiv2020

Comparative genomics and community curation further improve gene annotations in the nematode Pristionchus pacificus

BackgroundNematode model organisms such as Caenorhabditis elegans and Pristionchus pacificus are powerful systems for studying the evolution of gene function at a mechanistic level. However, the identification of P. pacificus orthologs of candidate genes known from C. elegans is complicated by the discrepancy in the quality of gene annotations, a common problem in nematode and invertebrate genomics. ResultsHere, we combine comparative genomic screens for suspicious gene models with community-based curation to further improve the quality of gene annotations in P. pacificus. We extend previous curations of one-to-one orthologs to larger gene families and also orphan genes. Cross-species comparisons of protein lengths and screens for atypical domain combinations and species-specific orphan genes resulted in 4,221 candidate genes that were subject to community-based curation. Corrections for 2,851 gene models were implemented in a new version of the P. pacificus gene annotations. The new set of gene annotations contains 28,896 genes and has a single copy ortholog completeness level of 97.6%. ConclusionsOur work demonstrates the effectiveness of comparative genomic screens to identify suspicious gene models and the scalability of community-based approaches to improve the quality of thousands of gene models. Similar community-based approaches can help to improve the quality of gene annotations in other invertebrate species, including parasitic nematodes.

genomics↗

bioRxiv2020

Museum phylogenomics of extinct Oryctes beetles from the Mascarene Islands

The evolution of island systems is characterized by processes that result in extreme morphological diversity, high endemism and high extinction rates. These dynamics can make phylogenetic reconstruction difficult, i.e. the extinct flightless Dodo from Mauritius was assigned to the family of doves only through DNA analysis of subfossils. Many insect species on islands have gone extinct through habitat loss, and face similar challenges to decipher their evolutionary history, however historical specimens have not yet been harnessed for phylogenomic reconstructions. Here, we employed historical museum specimens from the Mascarene Islands to generate the first whole-genome based phylogeny of three presumably extinct species of the rhinoceros beetle genus Oryctes. We compared their genomes with those of an extant Oryctes species from the island of Reunion, as well as a flightless Reunion-based species previously placed into the supposedly unrelated genus Marronus. We found that Marronus borbonicus belongs instead to the genus Oryctes and that the two Reunion-based species (O. borbonicus and M. borbonicus) are not sister taxa, suggesting two independent colonizations. The divergence time between them (<3Myr) overlaps with the volcanic formation of Reunion, likely indicating that M. borbonicus became flightless in situ. Our study showcases the power of genomes from insect museum specimens to address evolutionary questions in light of increasing extinction rates.

evolutionary biology↗

bioRxiv2019

Conserved nuclear receptors controlling a novel trait target fast-evolving genes expressed in a single cell

Environment shapes development through a phenomenon called developmental plasticity. Deciphering its genetic basis has implications for understanding evolution and adaptation to novel environments, yet molecular studies are scarce. Here, we expanded the gene regulatory network controlling predatory vs. non-predatory morphology in the nematode Pristionchus pacificus. First, we isolated a mutant in the nuclear hormone receptor nhr-1 with a previously unseen phenotypic effect. It disrupts mouth-form determination and results in animals combining features of both wild-type morphs. Further, we identified common targets of NHR-1 and the previously identified nuclear hormone receptor NHR-40 through transcriptomics. Unlike their highly conserved regulators, the target genes have no orthologs in Caenorhabditis elegans and likely result from lineage-specific expansions. An array of transcriptional reporters revealed co-expression of all tested targets in the same pharyngeal gland cell. The morphological remodeling of this cell accompanied the evolution of teeth and predation, linking rapid gene turnover with morphological innovations.

developmental biology↗