A single protein, termed Gag, is responsible for retrovirus particle assembly. After the assembled virion is released from the cell, Gag is cleaved at several sites by the viral protease (PR). The cleavages catalyzed by PR bring about a wide variety of physical changes in the particle, collectively termed maturation, and convert the particle into an infectious virion. In murine leukemia virus (MLV) maturation, Gag is cleaved at three sites, resulting in formation of the matrix (MA), p12, capsid (CA), and nucleocapsid (NC) proteins. We introduced mutations into MLV that inhibited cleavage at individual sites in Gag. All mutants had lost the intensely staining ring characteristic of immature particles; thus, no single cleavage event is required for this feature of maturation. Mutant virions in which MA was not cleaved from p12 were still infectious, with a specific infectivity only approximately 10-fold below that of the wild type. Particles in which p12 and CA could not be separated from each other were noninfectious and lacked a well-delineated core despite the presence of dense material in their interiors. In both of these mutants, the dimeric viral RNA had undergone the stabilization normally associated with maturation, suggesting that this change may depend upon the separation of CA from NC. Alteration of the C-terminal end of CA blocked CA-NC cleavage but also reduced the efficiency of particle formation and, in some cases, severely disrupted the ability of Gag to assemble into regular structures. This observation highlights the critical role of this region of Gag in assembly.
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http://dx.doi.org/10.1128/jvi.78.3.1411-1420.2004 | DOI Listing |
bioRxiv
January 2025
Department of Molecular and Cellular Biology, The Scripps Research Institute, La Jolla, CA 92037, United States.
Adoptive T-cell transfer has revolutionized the treatment of hematological malignancies. However, this approach has had very limited success in treating solid tumors, largely due to inadequate infiltration of vascularly administered T cells at tumor sites. The shear-resistant interaction between endothelial E-selectin and its cognate ligand expressed on leukocytes, sialyl Lewis X (sLe), is an essential prerequisite for extravasation of circulating leukocytes.
View Article and Find Full Text PDFRegen Ther
March 2025
Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo 180-8602, Japan.
Introduction: Intestinal lymphoma may be latent in some dogs with chronic inflammatory enteropathy. Mesenchymal stromal cells (MSCs) have potential therapeutic applications for refractory chronic inflammatory enteropathy, but their impact on the development of potential intestinal lymphomas has not yet been evaluated. Therefore, this study was performed to investigate the effect of canine adipose-derived MSCs (cADSCs) on the growth of canine lymphoma cell lines to assess the safety of MSC-based therapy in terms of pro- and anti-tumorigenic effects.
View Article and Find Full Text PDFJ Immunother Cancer
January 2025
Division of Tumor Immunology, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
Background: A number of immunotherapeutic approaches have been developed and are entering the clinic. Bispecific antibodies (BsAbs) are one of these modalities and induce robust efficacy by endogenous T cells in several hematological malignancies. However, most of the treated patients experience only a temporary benefit.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Hematology and Oncology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatric Metabolism and Inflammatory Diseases, Children's Hospital of Chongqing Medical University, No 136 Zhongshan 2 road, YuZhong district, Chongqing, 400014, China.
Genetic alterations play a pivotal role in leukemic clonal transformation, significantly influencing disease pathogenesis and clinical outcomes. Here, we report a novel fusion gene and investigate its pathogenic role in acute lymphoblastic leukemia (ALL). We engineer a transposon transfection system expressing the TOP2B::AFF2 transcript and introduce it into Ba/F3 cells.
View Article and Find Full Text PDFNat Commun
January 2025
Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Chronic lymphocytic leukemia is a malignant lymphoproliferative disorder for which primary or acquired drug resistance represents a major challenge. To investigate the underlying molecular mechanisms, we generate a mouse model of ibrutinib resistance, in which, after initial treatment response, relapse under therapy occurrs with an aggressive outgrowth of malignant cells, resembling observations in patients. A comparative analysis of exome, transcriptome and proteome of sorted leukemic murine cells during treatment and after relapse suggests alterations in the proteasome activity as a driver of ibrutinib resistance.
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