Biology subjects

Röseler, W.

Publications and source records attributed to Röseler, W..

3 recordsLinked to original sources

bioRxiv2024

Developmental small RNA transcriptomics reveals divergent evolution of the conserved microRNA miR-100 and the let-7-complex in nematodes

BackgroundOver the last three decades, small RNAs have emerged as one of the key post-transcriptional regulators, and are categorised into microRNAs (miRNAs), small interfering RNAs (siRNAs), and PIWI-interacting RNAs (piRNAs). Since their discovery as regulators of developmental timing in the nematode Caenorhabditis elegans, some miRNAs have been found to be highly conserved throughout animal evolution. miR-100 is one such highly conserved miRNA, possibly predating the origin of bilaterians. Furthermore, mir-100 is a member of the conserved let-7-complex, a locus containing three conserved miRNA-coding genes (mir-100, let-7, and mir-125/lin-4) that does not exist in the same arrangement in C. elegans. ResultsWe performed small RNA sequencing across four developmental time-points in the satellite nematode Pristionchus pacificus, identifying 64 novel and ontogenically specifically expressed miRNAs. We also identified miR-100 as the most abundant miRNA in post-embryonic juvenile stages. Additionally, P. pacificus exhibited a novel constellation of the let-7-complex, wherein mir-100 is closely linked to let-7, but without mir-125/lin-4 in the same locus. Mutants of mir-100 and let-7, individually as well as simultaneously, resulted in viable but developmentally defective worms, showing misregulation in collagen and astacin gene families. Interestingly, lin-4 mutants showed a delayed but otherwise normal development. ConclusionThis study provides the first developmental small RNA transcriptome of P. pacificus, providing a community resource for future evo-devo studies. Furthermore, we identify miR-100 as the most abundant ontogenically-specific miRNA, which, along with let-7, regulates normal development in P. pacificus. Lastly, we observe two alternative arrangements of the highly conserved miRNA locus let-7-complex.

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

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↗