{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nAlthough none of the provided abstracts explicitly mention SNORD83A, together they detail key functions of the surrogate light chain (SLC) components—VpreB and λ5—in pre‐B cell receptor (pre‐BCR) biology. In these studies, the SLC plays a central role in early B cell development: its association with the μ heavy chain forms the pre‐BCR that, upon surface expression, orchestrates critical developmental checkpoints. Notably, one study shows that even when all surrogate light chain components are absent, allelic exclusion of the immunoglobulin heavy chain is maintained despite an impaired clonal expansion of precursor B cells."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nAdditional work demonstrates that efficient binding of the pre‐BCR to stromal cells is mediated by unique, non-immunoglobulin domains within the surrogate λ5 chain and involves interactions with cell-surface heparan sulfate. This work supports the concept that pre‐BCR signals are initiated by extracellular ligands—such as heparan sulfate—engaging the receptor complex and ultimately modulating intracellular signaling cascades critical for B cell maturation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFurthermore, investigations into SLC gene regulation have highlighted that pre‐BCR signaling triggers the downregulation and allelic silencing of the surrogate light chain genes as precursor B cells transition from the pre-BI to pre-BII stage, a process contributing to the cessation of pre‐BCR-mediated proliferation. Complementary studies have also dissected the individual roles of VpreB and λ5 domains in receptor surface deposition and intracellular signal transduction, showing that while VpreB supports receptor stability at the cell surface, λ5’s non-immunoglobulin portion promotes receptor crosslinking and subsequent downregulation. Importantly, persistent or enhanced expression of SLC components beyond the pre‐B cell stage has been linked to the promotion of tolerance mechanisms, such as clonal deletion and anergy, thereby mitigating autoimmunity"}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": ";"}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": ";."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Takeyuki Shimizu, Cornelia Mundt, Steve Licence, et al. "}, {"type": "b", "children": [{"type": "t", "text": "VpreB1/VpreB2/lambda 5 triple-deficient mice show impaired B cell development but functional allelic exclusion of the IgH locus."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Immunol (2002)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.4049/jimmunol.168.12.6286"}], "href": "https://doi.org/10.4049/jimmunol.168.12.6286"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12055243"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12055243"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Harald Bradl, Jürgen Wittmann, Doreen Milius, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Interaction of murine precursor B cell receptor with stroma cells is controlled by the unique tail of lambda 5 and stroma cell-associated heparan sulfate."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Immunol (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.4049/jimmunol.171.5.2338"}], "href": "https://doi.org/10.4049/jimmunol.171.5.2338"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12928380"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12928380"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Mathew J Parker, Steve Licence, Lena Erlandsson, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The pre-B-cell receptor induces silencing of VpreB and lambda5 transcription."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "EMBO J (2005)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/sj.emboj.7600850"}], "href": "https://doi.org/10.1038/sj.emboj.7600850"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16281060"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16281060"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Marko Knoll, Yuki Yanagisawa, Szandor Simmons, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The non-Ig parts of the VpreB and λ5 proteins of the surrogate light chain play opposite roles in the surface representation of the precursor B cell receptor."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Immunol (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.4049/jimmunol.1200071"}], "href": "https://doi.org/10.4049/jimmunol.1200071"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "22566564"}], "href": "https://pubmed.ncbi.nlm.nih.gov/22566564"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Laurens P Kil, Odilia B J Corneth, Marjolein J W de Bruijn, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Surrogate light chain expression beyond the pre-B cell stage promotes tolerance in a dose-dependent fashion."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Autoimmun (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.jaut.2014.11.008"}], "href": "https://doi.org/10.1016/j.jaut.2014.11.008"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "25523463"}], "href": "https://pubmed.ncbi.nlm.nih.gov/25523463"}]}]}]}