Biology subjects

Wirth, S. A.

Publications and source records attributed to Wirth, S. A..

4 recordsLinked to original sources

bioRxiv2025

Exon-skipping and genetic compensation due to biallelic mutations in the neurodevelopmental disease gene LNPK

Homozygous loss-of-function mutations in LNPK, the gene encoding the endoplasmic reticulum-associated protein lunapark, have previously been linked to an autosomal recessive neurodevelopmental syndrome. Here, we describe an individual harboring compound heterozygous predicted splice site mutations with an overall matching phenotype. In cultured fibroblasts, these mutations result in a dearth of transcript and severe loss of protein, thereby establishing their likely pathogenicity. The underlying reduction in gene expression is due to the activation of the nonsense-mediated decay (NMD) pathway as a consequence of exon-skipping rather than intron retention, leading to aberrant transcripts. We further demonstrate that LNPK is subject to genetic compensation, as both cells from the affected individual and her mother exhibit a significant increase in transcript compared to a control cell line when treated with an inhibitor of NMD. Together, this report describes novel disease-causing variants in LNPK and reveals their impact on transcription and mRNA stability.

genetics↗

bioRxiv2025

CREPE (CREate Primers and Evaluate): a computational tool for large-scale primer design and specificity analysis

Polymerase chain reaction (PCR) is ubiquitous in biological research labs, as it is a fast, flexible, and cost-effective technique to amplify a DNA region of interest. However, manual primer design can be an error-prone and time-consuming process depending on the number and composition of target sites. While Primer3 has emerged as an accessible tool to solve some of these issues, additional computational pipelines are required for appropriate scaling. Moreover, this does not replace the manual confirmation of primer specificity (i.e., the assessment of off-targets). To overcome the challenges of large-scale primer design, we fused the functionality of Primer3 and In-Silico PCR (ISPCR); this integrated pipeline, CREPE (CREate Primers and Evaluate), performs primer design and specificity analysis through a custom evaluation script for any given number of target sites at scale. Its final output summarizes the lead forward and reverse primer pair for each target site, a measure of the likelihood of binding to off-targets, and additional information to aid decision-making. We provide this through a customized workflow for targeted amplicon sequencing (TAS) on a 150bp paired-end Illumina platform. Experimental testing showed successful amplification for more than 90% of primers deemed acceptable by CREPE.

genetics↗

bioRxiv2024

Production of biologically active human basic Fibroblast Growth Factor (hFGFb) using Nicotiana tabacum transplastomic plants

The use of plants as biofactories presents as an attractive technology with the potential to efficiently produce high-value human recombinant proteins in a cost-effective manner. Plastid genome transformation stands out for its possibility to accumulate recombinant proteins at elevated levels. Of particular interest are recombinant growth factors, given their applications in animal cell culture and regenerative medicine. In this study we produced recombinant human Fibroblast Growth Factor (rhFGFb), a crucial protein required for animal cell culture, in tobacco chloroplasts. We successfully generated two independent transplastomic lines that are homoplasmic and accumulate rhFGFb in their leaves. Furthermore, the produced rhFGFb demonstrated its biological activity by inducing proliferation in HEK293T cell lines. These results collectively underscore plastid genome transformation as a promising plant-based bioreactor for rhFGFb production. Main conclusionWe generated transplastomic tobacco lines that stably express a human Basic Fibroblast Growth Factor (hFGFb) in their chloroplasts stroma and purified a biologically active recombinant hFGFb.

bioengineering↗

bioRxiv2020

Temporal stability of human sperm mosaic mutations results in life-long threat of transmission to offspring

Every newborn harbors scores of new single nucleotide variants (SNVs) that may impact health and disease1-4; the majority of these are contributed by the paternal germ cells5. In some cases, these mutations are identifiable in a subset of the parents cells--a phenomenon called mosaicism, which is capable of producing disease recurrence6-8. Here, we provide a comprehensive analysis of male gonadal mosaic mutations, employing 300x whole genome sequencing (WGS) of blood and sperm in 17 healthy individuals, including assessment across multiple samples and age groups. Approximately 1 in 15 healthy males is predicted to harbor a transmissible, likely pathogenic exonic variant that is mosaic in his sperm. In general, only a third of sperm mosaic mutations were detectable in blood cells, all were remarkably stable over the course of months to years, and 23% were present in 5% or more of sperm cells. There was no evidence of age-dependent clonal expansion or collapse, as seen in hematopoiesis. Thus, despite the observed increase of mutations in offspring of men with advanced paternal age, detectable sperm mosaicism remains stable, represents a life-long transmission risk to offspring, and suggests a testis stem cell niche that prevents widespread clonality.

genomics↗