Biology subjects

Yoon, J.-K.

Publications and source records attributed to Yoon, J.-K..

3 recordsLinked to original sources

bioRxiv2024

Evolutionary unique N-glycan-dependent protein quality control system plays pivotal roles in cellular fitness and extracellular vesicle transport in Cryptococcus neoformans

A conserved N-glycan-dependent endoplasmic reticulum protein quality control (ERQC) system has evolved in eukaryotes to ensure accuracy during glycoprotein folding. The human pathogen Cryptococcus neoformans possesses a unique N-glycosylation pathway that affects microbial physiology and interactions with the infected host. To investigate the molecular features and functions of the ERQC system in C. neoformans, we characterized a set of mutants with deletion of genes coding for the ERQC sensor UDP-glucose:glycoprotein glucosyltransferase (UGG1) and putative 1,2-mannose-trimming enzymes (MNS1, MNS101, MNL1, and MNL2). The ugg1{Delta}, mns1{Delta}, mns101{Delta}, and mns1{Delta}101{Delta} mutants showed alterations in N-glycan profiles, defective cell surface organization, decreased survival in host cells, and varying degrees of reduced in vivo virulence. The ugg1{Delta} strain exhibited severely impaired extracellular secretion of capsular polysaccharides and virulence-related enzymes. Comparative transcriptome analysis showed the upregulation of protein folding, proteolysis, and cell wall remodeling genes, indicative of induced ER stress. However, no apparent changes were observed in the expression of genes involved in protein secretion or capsule biosynthesis. Additionally, extracellular vesicle (EV) analysis combined with proteomic analysis showed significant alterations in the number, size distribution, and cargo composition of EVs in ugg1{Delta}. These findings highlight the essential role of the functional ERQC system for cellular fitness under adverse conditions and proper EV-mediated transport of virulence factors, which are crucial for the full fungal pathogenicity of C. neoformans.

microbiology↗

bioRxiv2021

Expression Based Species Deconvolution and Realignment Removes Misalignent Error in Multi-species Single Cell Data

Although single-cell RNA sequencing of xenograft samples has been widely used, no comprehensive bioinformatics pipeline is available for human and mouse mixed single-cell analyses. Considering the numerous homologous genes across the human and mouse genomes, misalignment errors should be evaluated, and a new algorithm is required. We assessed the extents and effects of misalignment errors when using human and mouse combined reference data and developed a new bioinformatics pipeline with expression-based species deconvolution to minimize errors. We also evaluated false-positive signals for a species presumed to originate from ambient RNA of the other species and applied a computational method to remove them. Misaligned reads account for an average of 0.5% of total reads, but such reads were concentrated to few genes that were greatly affected. Human and mouse mixed single-cell data, analyzed using our pipeline, clustered well with unmixed data and showed higher k-nearest-neighbor batch effect test and Local Inverse Simpsons Index scores than those derived from Cell Ranger. We also applied our pipeline to multispecies multisample single-cell library containing breast cancer xenograft tissue and successfully identified all samples using genomic array and expression. Moreover, diverse cell types in the tumor microenvironment were well captured. We present our bioinformatics pipeline for mixed human and mouse single-cell data, which can also be applied to pooled libraries to obtain cost-effective single-cell data. We also address major consideration points when analyzing multispecies single-cell data for other applications.

bioinformatics↗

bioRxiv2020

Engineered Prime Editors with PAM flexibility

Although prime editors are a powerful tool for genome editing, which can generate various types of mutations such as nucleotide substitutions, insertions, and deletions in the genome without double-strand breaks or donor DNA, the conventional prime editors are still limited to its target scopes because of the PAM preference of the spCas9 protein. Here, we described the engineered prime editors to expand the range of their target sites using various PAM-flexible Cas9 variants.

bioengineering↗