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Wolfgang Wurst

Publications and source records attributed to Wolfgang Wurst.

13 recordsLinked to original sources
PubMed2026

Creating bottom-up RNA transfer vehicles from synthetic protein assemblies.

Evolution guides biological systems to populate ecological niches, with viruses among the most successful examples of this principle. Viruses evolved over billions of years to efficiently transfer genetic information. Although viruses are highly diverse, most have converged towards remarkable similarity in the size and shape of their capsids1,2. By contrast, generative models for protein design enable the creation of protein architectures that are absent from nature3-5. Here we investigate whether protein assemblies designed by artificial intelligence can be functionalized to construct nucleic acid transport vehicles that are independent of evolutionary trajectories. By combining natural protein domains with synthetic protein assemblies, we create more than 100 bottom-up RNA transfer vehicles with unique sizes and shapes. These vehicles surpass the RNA transfer efficiency of widely used delivery vehicles by several orders of magnitude. In addition, we demonstrate that their tropism can be programmed by incorporation of computationally designed peptide binders and use them to deliver therapeutically relevant cargo RNAs into a wide range of cellular models. We show the in vivo biodistribution of one of these vehicles in a mouse at near-single-cell resolution, confirm its safety, and use it to perform a gene-editing treatment strategy for Duchenne muscular dystrophy in patient-derived cells and a pig. Our work demonstrates how proteins created by generative artificial intelligence can be harnessed for the rational engineering of RNA transport systems with the desired properties by overcoming the limitations of natural protein diversity.

Journal Article↗
PubMed2003

A large-scale, gene-driven mutagenesis approach for the functional analysis of the mouse genome.

A major challenge of the postgenomic era is the functional characterization of every single gene within the mammalian genome. In an effort to address this challenge, we assembled a collection of mutations in mouse embryonic stem (ES) cells, which is the largest publicly accessible collection of such mutations to date. Using four different gene-trap vectors, we generated 5,142 sequences adjacent to the gene-trap integration sites (gene-trap sequence tags; http://genetrap.de) from >11,000 ES cell clones. Although most of the gene-trap vector insertions occurred randomly throughout the genome, we found both vector-independent and vector-specific integration "hot spots." Because >50% of the hot spots were vector-specific, we conclude that the most effective way to saturate the mouse genome with gene-trap insertions is by using a combination of gene-trap vectors. When a random sample of gene-trap integrations was passaged to the germ line, 59% (17 of 29) produced an observable phenotype in transgenic mice, a frequency similar to that achieved by conventional gene targeting. Thus, gene trapping allows a large-scale and cost-effective production of ES cell clones with mutations distributed throughout the genome, a resource likely to accelerate genome annotation and the in vivo modeling of human disease.

Animals↗
PubMed2003

Location and size of dopaminergic and serotonergic cell populations are controlled by the position of the midbrain-hindbrain organizer.

Midbrain dopaminergic and hindbrain serotonergic neurons play an important role in the modulation of behavior and are involved in a series of neuropsychiatric disorders. Despite the importance of these cells, little is known about the molecular mechanisms governing their development. During embryogenesis, midbrain dopaminergic neurons are specified rostral to the midbrain-hindbrain organizer (MHO), and hindbrain serotonergic neurons are specified caudal to it. We report that in transgenic mice in which Otx2 and accordingly the MHO are shifted caudally, the midbrain dopaminergic neuronal population expands to the ectopically positioned MHO and is enlarged. Complementary, the extension of the hindbrain serotonergic cell group is decreased. These changes are preserved in adulthood, and the additional, ectopic dopaminergic neurons project to the striatum, which is a proper dopaminergic target area. In addition, in mutants in which Otx2 and the MHO are shifted rostrally, dopaminergic and serotonergic neurons are relocated at the newly positioned MHO. However, in these mice, the size ratio between these two cell populations is changed in favor of the serotonergic cell population. To investigate whether the position of the MHO during embryogenesis is also of functional relevance for adult behavior, we tested mice with a caudally shifted MHO and report that these mutants show a higher locomotor activity. Together, we provide evidence that the position of the MHO determines the location and size of midbrain dopaminergic and hindbrain serotonergic cell populations in vivo. In addition, our data suggest that the position of the MHO during embryogenesis can modulate adult locomotor activity.

Animals↗
PubMed2003

FGFR1 is independently required in both developing mid- and hindbrain for sustained response to isthmic signals.

Fibroblast growth factors (FGFs) are signaling molecules of the isthmic organizer, which regulates development of the midbrain and cerebellum. Tissue-specific inactivation of one of the FGF receptor (FGFR) genes, Fgfr1, in the midbrain and rhombomere 1 of the hindbrain of mouse embryos results in deletion of the inferior colliculi in the posterior midbrain and vermis of the cerebellum. Analyses of both midbrain-hindbrain and midbrain-specific Fgfr1 mutants suggest that after establishment of the isthmic organizer, FGFR1 is needed for continued response to the isthmic signals, and that it has direct functions on both sides of the organizer. In addition, FGFR1 appears to modify cell adhesion properties critical for maintaining a coherent organizing center. This may be achieved by regulating expression of specific cell-adhesion molecules at the midbrain-hindbrain border.

Animals↗
PubMed2003

Otx dose-dependent integrated control of antero-posterior and dorso-ventral patterning of midbrain.

Organizing centers emit signaling molecules that specify different neuronal cell types at precise positions along the anterior-posterior (A-P) and dorsal-ventral (D-V) axes of neural tube during development. Here we report that reduction in Otx proteins near the alar-basal plate boundary (ABB) of murine midbrain resulted in a dorsal shift of Shh expression, and reduction in Otx proteins at the midbrain-hindbrain boundary (MHB) resulted in an anterior expansion of the Fgf8 domain. Our data thus indicate that an Otx dose-dependent repressive effect coordinates proper positioning of Shh and Fgf8 expression. Furthermore, this control is effective for conferring proper cell identity in the floor-plate region of midbrain and does not require an Otx2-specific property. We propose that this mechanism may provide both A-P and D-V positional information to neuronal precursors located within the midbrain.

Animals↗
PubMed2003

Hypogonadotropic hypogonadism and peripheral neuropathy in Ebf2-null mice.

Olf/Ebf transcription factors have been implicated in numerous developmental processes, ranging from B-cell development to neuronal differentiation. We describe mice that carry a targeted deletion within the Ebf2 (O/E3) gene. In Ebf2-null mutants, because of defective migration of gonadotropin releasing hormone-synthesizing neurons, formation of the neuroendocrine axis (which is essential for pubertal development) is impaired, leading to secondary hypogonadism. In addition, Ebf2(-/-) peripheral nerves feature defective axon sorting, hypomyelination, segmental dysmyelination and axonal damage, accompanied by a sharp decrease in motor nerve conduction velocity. Ebf2-null mice reveal a novel genetic cause of hypogonadotropic hypogonadism and peripheral neuropathy in the mouse, disclosing an important role for Ebf2 in neuronal migration and nerve development.

Animals↗
PubMed2003

The isthmic organizer signal FGF8 is required for cell survival in the prospective midbrain and cerebellum.

Numerous studies have demonstrated that the midbrain and cerebellum develop from a region of the early neural tube comprising two distinct territories known as the mesencephalon (mes) and rostral metencephalon (met; rhombomere 1), respectively. Development of the mes and met is thought to be regulated by molecules produced by a signaling center, termed the isthmic organizer (IsO), which is localized at the boundary between them. FGF8 and WNT1 have been implicated as key components of IsO signaling activity, and previous studies have shown that in Wnt1(-/-) embryos, the mes/met is deleted by the 30 somite stage ( approximately E10) (McMahon, A. P. and Bradley, A. (1990) Cell 62, 1073-1085). We have studied the function of FGF8 in mouse mes/met development using a conditional gene inactivation approach. In our mutant embryos, Fgf8 expression was transiently detected, but then was eliminated in the mes/met by the 10 somite stage ( approximately E8.75). This resulted in a failure to maintain expression of Wnt1 as well as Fgf17, Fgf18, and Gbx2 in the mes/met at early somite stages, and in the absence of the midbrain and cerebellum at E17.5. We show that a major cause of the deletion of these structures is ectopic cell death in the mes/met between the 7 and 30 somite stages. Interestingly, we found that the prospective midbrain was deleted at an earlier stage than the prospective cerebellum. We observed a remarkably similar pattern of cell death in Wnt1 null homozygotes, and also detected ectopic mes/met cell death in En1 null homozygotes. Our data show that Fgf8 is part of a complex gene regulatory network that is essential for cell survival in the mes/met.

Animals↗
PubMed2002

Miswiring of limbic thalamocortical projections in the absence of ephrin-A5.

Axon guidance cues of the ephrin ligand family have been hypothesized to regulate the formation of thalamocortical connections, but in vivo evidence for such a role has not been examined directly. To test whether ephrin-mediated repulsive cues participate in sorting the projections originating from distinct thalamic nuclei, we analyzed the organization of somatosensory and anterior cingulate afferents postnatally in mice lacking ephrin-A5 gene expression. Projections from ventrobasal and laterodorsal nuclei to their respective sensory and limbic cortical areas developed normally. However, a portion of limbic thalamic neurons from the laterodorsal nucleus also formed additional projections to somatosensory cortical territories, thus maintaining inappropriate dual projections to multiple cortical regions. These results suggest that ephrin-A5 is not required for the formation of normal cortical projections from the appropriate thalamic nuclei, but rather acts as a guidance cue that restricts limbic thalamic axons from inappropriate neocortical regions.

Animals↗
PubMed2002

Enhanced and delayed stress-induced alcohol drinking in mice lacking functional CRH1 receptors.

There is a relation between stress and alcohol drinking. We show that the corticotropin-releasing hormone (CRH) system that mediates endocrine and behavioral responses to stress plays a role in the control of long-term alcohol drinking. In mice lacking a functional CRH1 receptor, stress leads to enhanced and progressively increasing alcohol intake. The effect of repeated stress on alcohol drinking behavior appeared with a delay and persisted throughout life. It was associated with an up-regulation of the N-methyl-d-aspartate receptor subunit NR2B. Alterations in the CRH1 receptor gene and adaptional changes in NR2B subunits may constitute a genetic risk factor for stress-induced alcohol drinking and alcoholism.

Action Potentials↗
PubMed2002

Permutation-validated principal components analysis of microarray data.

BACKGROUND: In microarray data analysis, the comparison of gene-expression profiles with respect to different conditions and the selection of biologically interesting genes are crucial tasks. Multivariate statistical methods have been applied to analyze these large datasets. Less work has been published concerning the assessment of the reliability of gene-selection procedures. Here we describe a method to assess reliability in multivariate microarray data analysis using permutation-validated principal components analysis (PCA). The approach is designed for microarray data with a group structure. RESULTS: We used PCA to detect the major sources of variance underlying the hybridization conditions followed by gene selection based on PCA-derived and permutation-based test statistics. We validated our method by applying it to well characterized yeast cell-cycle data and to two datasets from our laboratory. We could describe the major sources of variance, select informative genes and visualize the relationship of genes and arrays. We observed differences in the level of the explained variance and the interpretability of the selected genes. CONCLUSIONS: Combining data visualization and permutation-based gene selection, permutation-validated PCA enables one to illustrate gene-expression variance between several conditions and to select genes by taking into account the relationship of between-group to within-group variance of genes. The method can be used to extract the leading sources of variance from microarray data, to visualize relationships between genes and hybridizations and to select informative genes in a statistically reliable manner. This selection accounts for the level of reproducibility of replicates or group structure as well as gene-specific scatter. Visualization of the data can support a straightforward biological interpretation.

Animals↗
PubMed2002

mPet-1, a mouse ETS-domain transcription factor, is expressed in central serotonergic neurons.

Here we describe the expression pattern of a previously unknown mouse gene mPet-1. The isolated cDNA codes for an ETS-domain transcription factor of 237 amino acids in length, which is localized to the nucleus. mPet-1 is a member of the winged helix transcription factor gene family like its rat homologue Pet-1 and the human homologue FEV. The start ATG of mPet-1 and the size of the predicted protein are identical to the human FEV. The mPet-1 protein is clearly smaller since it lacks the first 103 N-terminal amino acids of rat Pet-1. mPet- 1 is expressed in central serotonergic (5-hydroxytryptaminergic) neurons located in the mes-/metencephalic raphe nuclei from E11 on until adulthood. In these regions mPet-1 expression co-localizes precisely with the serotonin transporter (Sert),which it initially precedes. Interestingly, mPet-1 was not found in neurons transiently expressing Sert.

Amino Acid Sequence↗
PubMed2002

Nephrin TRAP mice lack slit diaphragms and show fibrotic glomeruli and cystic tubular lesions.

The molecular mechanisms maintaining glomerular filtration barrier are under intensive study. This study describes a mutant Nphs1 mouse line generated by gene-trapping. Nephrin, encoded by Nphs1, is a structural protein of interpodocyte filtration slits crucial for formation of primary urine. Nephrin(trap/trap) mutants show characteristic features of proteinuric disease and die soon after birth. Morphologically, fibrotic glomeruli with distorted structures and cystic tubular lesions were observed, but no prominent changes in the branching morphogenesis of the developing collecting ducts could be found. Western blotting and immunohistochemical analyses confirmed the absence of nephrin in nephrin(trap/trap) glomeruli. The immunohistochemical staining showed also that the interaction partner of nephrin, CD2-associated protein (CD2AP), and the slit-diaphragm-associated protein, ZO-1alpha (-), appeared unchanged, whereas the major anionic apical membrane protein of podocytes, podocalyxin, somewhat punctate as compared with the wild-type (wt) and nephrin(wt/trap) stainings. Electron microscopy revealed that >90% of the podocyte foot processes were fused. The remaining interpodocyte junctions lacked slit diaphragms and, instead, showed tight adhering areas. In the heterozygote glomeruli, approximately one third of the foot processes were fused and real-time RT-PCR showed >60% decrease of nephrin-specific transcripts. These results show an effective nephrin gene elimination, resulting in a phenotype that resembles human congenital nephrotic syndrome. Although the nephrin(trap/trap) mice can be used to study the pathophysiology of the disease, the heterozygous mice may provide a useful model to study the gene dose effect of this crucial protein of the glomerular filtration barrier.

Animals↗