The Ig heavy chain (IgH) locus is controlled by multiple regulatory sequences mapping both within the IgH transcription unit (E mu) and downstream (3') of IgH coding sequences (hs3a, hs1,2, hs3b and hs4). Enhancer knockout studies in mice have implicated E mu in the control of IgH variable region gene assembly, but single-enhancer knockouts involving the 3' IgH enhancers have yet to shed light on their function. Transfection studies in mice and cell lines have suggested that the 3' enhancers behave similarly to a locus control region as first identified in the beta-globin locus. We have exploited this property to form mini-loci in a surface Ig(+) and an Ig-secreting cell line as a means for studying the functions of the 3' IgH enhancers. Importantly, this experimental system allows for the analysis of enhancer function within the context of chromatin. The mini-loci consisted of an Ig gamma 2b transcription unit linked to the four murine 3' IgH enhancers. Using targeted deletions of enhancer pairs within these mini-loci, we have discovered a critical and apparently developmentally regulated role for the hs3b/hs4 enhancer pair in IgH transgene expression.
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http://dx.doi.org/10.1093/intimm/13.8.1003 | DOI Listing |
Dentomaxillofac Radiol
January 2025
Aiiso Yufeng Li Family Department of Chemical and Nano Engineering, University of California San Diego, La Jolla, California 92093, USA.
Objectives: To identify landmarks in ultrasound periodontal images and automate the image-based measurements of gingival recession (iGR), gingival height (iGH), and alveolar bone level (iABL) using machine learning.
Methods: We imaged 184 teeth from 29 human subjects. The dataset included 1580 frames for training and validating the U-Net CNN machine learning model, and 250 frames from new teeth that were not used in training for testing the generalization performance.
Hum Pathol
October 2024
Hematopathology, Division of Pathology and Laboratory Medicine. The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. Electronic address:
Front Immunol
October 2024
The International ImMunoGeneTics® Information System (IMGT®), Institute of Human Genetics (IGH), National Center for Scientific Research (CNRS), University of Montpellier (UM), Montpellier, France.
Through the analysis of immunoglobulin genes at the IGH, IGK, and IGL loci from four genome assemblies, IMGT provides an in-depth overview of these loci and their individual variations in a species closely related to humans. The similarity between gorilla and human IG gene organization allowed the assignment of gorilla IG gene names based on their human counterparts. This study revealed significant findings, including variability in the IGH locus, the presence of known and new copy number variations (CNVs), and the accurate estimation of IGHG genes.
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October 2024
Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, MA.
Rationale: Cigarette smoking (CS) impairs B cell function and antibody production, increasing infection risk. The impact of e-cigarette use ('vaping') and combined CS and vaping ('dual-use') on B cell activity is unclear.
Objective: To examine B cell receptor sequencing (BCR-seq) profiles associated with CS, vaping, dual-use, COPD-related outcomes, and demographic factors.
Nucleic Acids Res
November 2024
UMR CNRS7276, Inserm1262, Université de Limoges: Contrôle de la Réponse Immune B et des Lymphoproliférations, Team 2, B-NATION: B Cell Nuclear Architecture, Immunoglobulin Genes and Oncogenes, 2, rue du Dr. Marcland, 87025 Limoges, France.
In B lymphocytes, class switch recombination (CSR) is an essential process that adapts immunoglobulin (Ig) subtypes to antigen response. Taking place within the Ig heavy chain (IgH) locus, CSR needs controlled transcription of targeted regions governed by the IgH 3' regulatory region (3'RR). This super-enhancer is composed of four core enhancers surrounded by inverted repeated sequences, forming a quasi-palindrome.
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