TCR zeta chain lacking exon 7 in two patients with systemic lupus erythematosus.
To address the molecular mechanism underlying the functional defects of peripheral T cells in systemic lupus erythematosus (SLE), we focused on early signaling events. We demonstrated that protein expression of the TCR zeta chain was significantly decreased in peripheral T cells from patients with SLE compared to normal controls and patients with systemic sclerosis (SSc). Among those patients showing decreased TCR zeta chain expression, we found two patients with pronounced TCR zeta chain abnormalities, including an aberrant 14 kDa form in one and only trace expression in the other. RT-PCR, SSCP and subsequent cloning of the transcripts revealed that bases 468503, corresponding to exon 7, were deleted in both patients. Since exon 7 spans the GTP/GDP binding site and N-terminal tyrosine in the third ITAM domain of TCR zeta chain, the transcript lacking exon 7 may be responsible for altered signal transduction via TCR in these SLE patients.
Department of Internal Medicine, Saitama Medical Center, Saitama Medical School, Kawagoe, Japan.
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Takeuchi
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Tsuzaka
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Pang
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Amano
J
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Koide
T
T
Abe
D000328:Adult; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005091:Exons; D005260:Female; D017353:Gene Deletion; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008875:Middle Aged; D008969:Molecular Sequence Data; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D013601:T-Lymphocytes / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic; D014443:Tyrosine / Q000378:metabolism
D018076:DNA, Complementary; D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain; D014443:Tyrosine