Biology subjects

Artamonov, M.

Publications and source records attributed to Artamonov, M..

3 recordsLinked to original sources

bioRxiv2025

Comprehensive Transcriptome Annotation of Thousands of HIV-1 Genomes

Alternative splicing in HIV-1 has been a central focus of decades of research, uncovering key mechanisms of viral gene regulation, immune evasion, and therapeutic response - yet, no reference resource has existed to support transcriptome-wide analysis, limiting adoption of modern computational methods. We present HIV Atlas (https://ccb.jhu.edu/HIV_Atlas), the first reference-quality annotation of HIV-1 and SIV transcriptional diversity. We manually curated transcriptomes for HIV-1HXB2 and SIVmac239 and developed Vira, an automated annotation-transfer method specifically designed to address unique challenges of viral genome biology, to generate high-quality annotations for 2,077 complete HIV-1 genomes. Using the resources presented in our work, we evaluated conservation of splice sites, revealing near-perfect preservation of major donors and acceptors. Furthermore, using several public datasets, we demonstrate how HIV Atlas enhances methodology, improves the quality and novelty of results, and opens novel avenues for research, supporting more accurate and comprehensive analyses of bulk, single-cell, and spatial RNA-seq in HIV-1 studies.

genomics↗

bioRxiv2023

p90RSK2, a new MLCK, rescues contractility in myosin light chain kinase null smooth muscle

BackgroundPhosphorylation of smooth muscle (SM) myosin regulatory light chain (RLC20) is a critical switch leading to contraction or cell migration. The canonical view held that the only kinase catalyzing this reaction is the short isoform of myosin light chain kinase (MLCK1). Auxiliary kinases may be involved and play a vital role in blood pressure homeostasis. We have previously reported that p90 ribosomal S6 kinase (RSK2) functions as such a kinase, in parallel with the classical MLCK1, contributing [~]25% of the maximal myogenic force in resistance arteries and regulating blood pressure. Here, we take advantage of a MLCK1 null mouse to further test our hypothesis that RSK2 can function as an MLCK, playing a significant physiological role in SM contractility. MethodsFetal (E14.5-18.5) SM tissues were used as embryos die at birth. We investigated the necessity of MLCK for contractility, cell migration and fetal development and determined the ability of RSK2 kinase to compensate for the lack of MLCK and characterized its signaling pathway in SM. ResultsAgonists induced contraction and RLC20 phosphorylation in mylk1-/- SM, that was inhibited by RSK2 inhibitors. Embryos developed and cells migrated in the absence of MLCK. The pCa-tension relationships in WT vs mylk1-/- muscles demonstrated a Ca2+-dependency due to the Ca2+-dependent tyrosine kinase Pyk2, known to activate PDK1 that phosphorylates and fully activates RSK2. The magnitude of contractile responses was similar upon addition of GTP{gamma}S to activate the RhoA/ROCK pathway. The Ca2+-independent component was through activation of Erk1/2/PDK1/RSK2 leading to direct phosphorylation of RLC20, to increase contraction. RSK2, PDK1, Erk1/2 and MLCK formed a signaling complex on the actin filament, optimally positioning them for interaction with adjacent myosin heads. ConclusionsRSK2 signaling constitutes a new third signaling pathway, in addition to the established Ca2+/CAM/MLCK and RhoA/ROCK pathways to regulate SM contractility and cell migration.

cell biology↗

bioRxiv2021

Molecular probes of spike ectodomain and its subdomains for SARS-CoV-2 variants, Alpha through Omicron

Since the outbreak of the COVID-19 pandemic, widespread infections have allowed SARS-CoV-2 to evolve in human, leading to the emergence of multiple circulating variants. Some of these variants show increased resistance to vaccines, convalescent plasma, or monoclonal antibodies. In particular, mutations in the SARS-CoV-2 spike have drawn attention. To facilitate the isolation of neutralizing antibodies and the monitoring the vaccine effectiveness against these variants, we designed and produced biotin-labeled molecular probes of variant SARS-CoV-2 spikes and their subdomains, using a structure-based construct design that incorporated an N-terminal purification tag, a specific amino acid sequence for protease cleavage, the variant spike-based region of interest, and a C-terminal sequence targeted by biotin ligase. These probes could be produced by a single step using in-process biotinylation and purification. We characterized the physical properties and antigenicity of these probes, comprising the N-terminal domain (NTD), the receptor-binding domain (RBD), the RBD and subdomain 1 (RBD-SD1), and the prefusion-stabilized spike ectodomain (S2P) with sequences from SARS-CoV-2 variants of concern or of interest, including variants Alpha, Beta, Gamma, Epsilon, Iota, Kappa, Delta, Lambda, Mu, and Omicron. We functionally validated probes by using yeast expressing a panel of nine SARS-CoV-2 spike-binding antibodies and confirmed sorting capabilities of variant probes using yeast displaying libraries of plasma antibodies from COVID-19 convalescent donors. We deposited these constructs to Addgene to enable their dissemination. Overall, this study describes a matrix of SARS-CoV-2 variant molecular probes that allow for assessment of immune responses, identification of serum antibody specificity, and isolation and characterization of neutralizing antibodies.

immunology↗