TY - JOUR
T1 - Alternative UNC13D Promoter Encodes a Functional Munc13-4 Isoform Predominantly Expressed in Lymphocytes and Platelets
AU - Galgano, Donatella
AU - Soheili, Tayebeh
AU - Voss, Matthias
AU - Torralba-Raga, Lamberto
AU - Tesi, Bianca
AU - Cichocki, Frank
AU - Andre, Isabelle
AU - Rettig, Jens
AU - Cavazzana, Marina
AU - Bryceson, Yenan
N1 - Publisher Copyright:
© Copyright © 2020 Galgano, Soheili, Voss, Torralba-Raga, Tesi, Cichocki, Andre, Rettig, Cavazzana and Bryceson.
PY - 2020/6/9
Y1 - 2020/6/9
N2 - Autosomal recessive mutations in genes required for cytotoxicity are causative of a life-threatening, early-onset hyperinflammatory syndrome termed familial hemophagocytic lymphohistiocytosis (FHL). Mutations in UNC13D cause FHL type 3. UNC13D encodes Munc13-4, a member of the Unc13 protein family which control SNARE complex formation and vesicle fusion. We have previously identified FHL3-associated mutations in the first intron of UNC13D which control transcription from an alternative transcriptional start site. Using isoform specific antibodies, we demonstrate that this alternative Munc13-4 isoform with a unique N-terminus is preferentially expressed in human lymphocytes and platelets, as compared to the conventional isoform that was mostly expressed in monocytes and neutrophils. The distinct N-terminal of the two isoforms did not impact on Munc13-4 localization or trafficking to the immunological synapse of cytotoxic T cells. Moreover, ectopic expression of both isoforms efficiently restored exocytosis by FHL3 patient-derived Munc13-4 deficient T cells. Thus, we demonstrate that the conventional and alternative Munc13-4 isoforms have different expression pattern in hematopoietic cell subsets, but display similar localization and contribution to T cell exocytosis. The use of an alternative transcriptional starting site (TSS) in lymphocytes and platelets could be selected for increasing the overall levels of Munc13-4 expression for efficient secretory granule release.
AB - Autosomal recessive mutations in genes required for cytotoxicity are causative of a life-threatening, early-onset hyperinflammatory syndrome termed familial hemophagocytic lymphohistiocytosis (FHL). Mutations in UNC13D cause FHL type 3. UNC13D encodes Munc13-4, a member of the Unc13 protein family which control SNARE complex formation and vesicle fusion. We have previously identified FHL3-associated mutations in the first intron of UNC13D which control transcription from an alternative transcriptional start site. Using isoform specific antibodies, we demonstrate that this alternative Munc13-4 isoform with a unique N-terminus is preferentially expressed in human lymphocytes and platelets, as compared to the conventional isoform that was mostly expressed in monocytes and neutrophils. The distinct N-terminal of the two isoforms did not impact on Munc13-4 localization or trafficking to the immunological synapse of cytotoxic T cells. Moreover, ectopic expression of both isoforms efficiently restored exocytosis by FHL3 patient-derived Munc13-4 deficient T cells. Thus, we demonstrate that the conventional and alternative Munc13-4 isoforms have different expression pattern in hematopoietic cell subsets, but display similar localization and contribution to T cell exocytosis. The use of an alternative transcriptional starting site (TSS) in lymphocytes and platelets could be selected for increasing the overall levels of Munc13-4 expression for efficient secretory granule release.
KW - UNC13D
KW - alternative intronic promoter/isoform
KW - familial hemophagocytic lymphohistiocytosis type 3
KW - intronic mutation
KW - lymphocyte cytotoxicity
KW - primary immunodeficiency
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U2 - 10.3389/fimmu.2020.01154
DO - 10.3389/fimmu.2020.01154
M3 - Article
C2 - 32582217
AN - SCOPUS:85087024132
SN - 1664-3224
VL - 11
JO - Frontiers in immunology
JF - Frontiers in immunology
M1 - 1154
ER -