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Titolo:
ANALYSIS OF THE HUMAN CD21 TRANSCRIPTION UNIT REVEALS DIFFERENTIAL SPLICING OF EXON-11 IN MATURE TRANSCRIPTS AND EXCLUDES ALTERNATIVE SPLICING AS THE MECHANISM CAUSING SOLUBILIZATION OF CD21
Autore:
ILLGES H; BRAUN M; PETER HH; MELCHERS I;
Indirizzi:
UNIV FREIBURG,MED CTR,CLIN RES UNIT RHEUMATOL,BREISACHERSTR 64 D-79106 FREIBURG GERMANY UNIV FREIBURG,MED CTR,DIV CLIN IMMUNOL & RHEUMATOL D-7800 FREIBURG GERMANY
Titolo Testata:
Molecular immunology
fascicolo: 10, volume: 34, anno: 1997,
pagine: 683 - 693
SICI:
0161-5890(1997)34:10<683:AOTHCT>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
EPSTEIN-BARR-VIRUS; COMPLEMENT RECEPTOR TYPE-2; HUMAN LYMPHOCYTES-B; INTERFERON-ALPHA RECEPTOR; T-DEPENDENT ANTIGEN; LEUKEMIA-CELL-LINE; C3D RECEPTOR; MONOCLONAL-ANTIBODIES; ANTI-CD21 ANTIBODIES; IMMUNE-RESPONSE;
Keywords:
CD21; ALTERNATIVE SPLICING; SOLUBLE CD21; EXON 11; CR-2;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
56
Recensione:
Indirizzi per estratti:
Citazione:
H. Illges et al., "ANALYSIS OF THE HUMAN CD21 TRANSCRIPTION UNIT REVEALS DIFFERENTIAL SPLICING OF EXON-11 IN MATURE TRANSCRIPTS AND EXCLUDES ALTERNATIVE SPLICING AS THE MECHANISM CAUSING SOLUBILIZATION OF CD21", Molecular immunology, 34(10), 1997, pp. 683-693

Abstract

CD21 is found in a soluble form at low levels in normal human sera and at elevated levels in sera from patients with EBV-associated diseases and B-CLL. Ablation of complement, injection of recombinant soluble CD21 and knock-out of CD21 in mice by gene targeting interfere with T-cell-dependent immune responses, suggesting that in vivo-generated soluble CD21 may exert immunoregulatory functions. Soluble CD21 has a molecular weight of 130 000/135 000, which is equivalent to the entire extracellular domain. Soluble forms of membrane-anchored molecules may be generated by proteolytic cleavage of the extracellular portion or bythe exclusion of the hydrophobic transmembrane region via alternativesplicing. To delineate whether alternative splicing of CD21 mRNA creates transcripts encoding for the soluble form of CD21 we analyzed by PCR CD21 expression in PBLs, spleen, tonsils, bone marrow and in various cell lines. We found that all CD21 mRNA species contained the transmembrane exons, thus excluding alternative splicing as a factor contributing to the serum pool of soluble CD21. Differential splicing of the CD21 transcription unit has also been suggested for exon 11. Within the CD21 gene exons 3, 7 and 11 have a high degree of homology. However,we found in malignant human cell lines and primary lymphocytes from blood, bone marrow, tonsils and spleen that exon 11, but not exon 3 or 7, is subject to alternative splicing. We cloned and sequenced the intron preceding exon 11 and found that the surrounding splice sites match consensus splice sites. In conclusion, we show that human CD21 exon 11 is alternatively spliced in malignant cell lines of lymphoid originand in purified lymphocytes from blood, tonsils, bone marrow and spleen. We found that both exon 11 lacking and exon 11 containing transcripts are always coexpressed and the ratio of of the two forms is > 1. Moreover, we exclude the possibility that alternative splicing of the transmembrane region is the mechanism leading to soluble CD21. (C) 1997Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 00:44:41