Biology subjects

Lang, G.

Publications and source records attributed to Lang, G..

5 recordsLinked to original sources

bioRxiv2024

Cytoduction preserves genetic diversity following plasmid transfer into pooled yeast libraries

Much of our understanding of functional genomics derives from insights gained from large strain libraries including the yeast deletion collection, the GFP and TAP-tagged libraries, QTL mapping populations, among others [1-5]. A limitation of these libraries is that it is not easy to introduce reporters or make genetic perturbations to all strains in these collections. Tools such as Synthetic Genetic Arrays allow for the genetic manipulation of these libraries but are labor intensive and require specialized equipment for high throughput pinning [6]. Manipulating a diverse library en mass without losing diversity remains challenging. Ultimately, this limitation stems from the inefficiency of transformation, which is the standard method for genetic manipulation in yeast. Here, we develop a method that uses cytoduction (mating without nuclear fusion) to transfer plasmids directionally from a "Donor" to a diverse pool of "Recipient" strains. Because cytoduction uses mating, it is a natural process and is orders-of-magnitude more efficient than transformation, enabling the introduction of plasmids into high-diversity libraries with minimal impact on the diversity of the population.

genetics↗

bioRxiv2023

The central nervous system is a potential reservoir and possible origin of drug resistance in HBV

The significance of HBV in cerebrospinal fluid (CSF) is unclear. In the present study, synchronous serum and CSF samples were collected from 13 patients. HBV-DNA, full-length genome, quasispecies, phylogenetic tree, compartmentalization and mutation of reverse transcriptase (RT) region analyses were performed based on PCR and sequencing methods. We found HBV-DNA was detected in the CSF of 3 antiviral-naive patients and one patient after successful antiviral therapy. Complete full-length HBV genomes were isolated from the CSF of 5 patients, including 2 patients with undetectable serum HBV-DNA. Ten patients exhibited distinct CSF-serum quasispecies, 8 harbored independent CSF-serum genetic compartmentalization and phylogenetic trees, and 5 patients presented lamivudine/entecavir-associated resistance mutations in only the CSF. The frequencies of rtL180M and rtM204I/V mutations in both serum and CSF were higher in HIV/HBV-coinfected patients than in HBV-monoinfected patients (serum: rtL180M: 3.9% vs. 0, P = 0.004; rtM204I/V: 21.3% vs. 0, P < 0.001; CSF: rtL180M: 7.6% vs. 0, P = 0.026; rtM204I/V 7.6% vs. 1.6%, P = 0.097). Our data suggested CSF is a potential HBV reservoir, and HBV in CSF harbors distinct evolution and mutation models from that in serum. HIV infection increases the possibility of HBV rtL180M and rtM204I/V mutations in both serum and CSF.

evolutionary biology↗

bioRxiv2021

Analogs of the Dopamine Metabolite 5,6-Dihydroxyindole Bind Directly to and Activate the Nuclear Receptor Nurr1 (NR4A2)

The nuclear receptor-related 1 protein, Nurr1, is a transcription factor critical for the development and maintenance of dopamine-producing neurons in the substantia nigra pars compacta, a cell population that progressively loses the ability to make dopamine and degenerates in Parkinsons disease. Recently, we demonstrated that Nurr1 binds directly to and is regulated by the endogenous dopamine metabolite 5,6-dihydroxyindole (DHI). Unfortunately, DHI is an unstable compound, and thus a poor tool for studying Nurr1 function. Here we report that 5-chloroindole, an unreactive analog of DHI, binds directly to the Nurr1 ligand binding domain with micromolar affinity and stimulates the activity of Nurr1, including the transcription of genes governing the synthesis and packaging of dopamine.

neuroscience↗

bioRxiv2021

Structure-based design of a highly stable, covalently-linked SARS-CoV-2 spike trimer with improved structural properties and immunogenicity

The continued threat of SARS-CoV-2 to global health necessitates development of improved research tools and vaccines. We present an improved SARS-CoV-2 spike ectodomain, "VFLIP", bearing five proline substitutions, a flexible cleavage site linker, and an inter-protomer disulfide bond. VFLIP displays significantly improved stability, high-yield production and retains its trimeric state without exogenous trimerization motifs. High-resolution cryo-EM and glycan profiling reveal that the VFLIP quaternary structure and glycosylation mimic the native spike on the viral surface. Further, VFLIP has enhanced affinity and binding kinetics relative to other stabilized spike proteins for antibodies in the Coronavirus Immunotherapeutic Consortium (CoVIC), and mice immunized with VFLIP exhibit potent neutralizing antibody responses against wild-type and B.1.351 live SARS-CoV-2. Taken together, VFLIP represents an improved tool for diagnostics, structural biology, antibody discovery, and vaccine design.

microbiology↗

bioRxiv2020

Dynamic spatiotemporal coordination of neural stem cell fate decisions through local feedback in the adult vertebrate brain

Neural stem cell (NSC) populations persist in the adult vertebrate brain over a life time, and their homeostasis is controlled at the population level. The nature and properties of these coordination mechanisms remain unknown. Here we combine dynamic imaging of entire NSC populations in their in vivo niche over weeks, pharmacological manipulations, mathematical modeling and spatial statistics, and demonstrate that NSCs use spatiotemporally resolved local feedbacks to coordinate their decision to divide. These involve a Notch-mediated inhibition from transient neural progenitors, and a dispersion effect from dividing NSCs themselves, exerted with a delay of 9-12 days. Simulations from a stochastic NSC lattice model capturing these interactions demonstrate that they are linked by lineage progression and control the spatiotemporal distribution of output neurons. These results highlight how local and temporally delayed interactions occurring between brain germinal cells generate self-propagating dynamics that maintain NSC population homeostasis with specific spatiotemporal correlations.

neuroscience↗