International Immunology, Vol 10, 815-821, Copyright © 1998 by Oxford University Press
T Maeda, DR Webb, J Chen, T Kobata, S Hirose, T Shirai, K Takabayashi, K Nishioka and T Sumida
The P8.6 gene is encoded upstream of the mouse TCR Valpha1 gene in the
anti-sense strand and its gene product contains the proline-rich region and
tyrosine-isoleucine (Y-I) motif, which are consensus sequences for the SH2
and SH3 binding motifs respectively. It was found that this protein is
highly homologous to Igbeta. We also found that the P8.6 protein associates
with a 170 kDa phosphorylated protein in vivo. To examine the polymorphism
of the P8.6 gene, we carried out a single- strand conformation polymorphism
analysis and found that the P8.6 gene comprises a family of at least 13
independent genes arising from single or multiple mutations. The mutated
P8.6 gene with the Y-L motif was deleted, especially in NZW and BXSB mice,
whereas normal BALB/c mice have a P8.6 gene bearing both the Y-I and Y-L
motifs, suggesting a dysregulation in signaling through the B cell receptor
or TCR in these two autoimmune mice. Functional analysis using transfectant
cells carrying P8.6-1 (Y-I motif) and P8.6-3 (Y-L motif) clearly
demonstrated that P8.6-3 gene inhibited the signal transduction upon the
stimulation of ionomycin and cell growth. The TANYSNI sequence has been
proposed as the immunoreceptor tyrosine-based inhibitory motif, this motif
is replaced by AANYSNI in the NZW mice. In conclusion, some P8.6 are
deleted in particular autoimmune-prone mice.
ARTICLES
Deletion of signaling molecule genes resembling the cytoplasmic domain of Igbeta in autoimmune-prone mice
Division of Rheumatology, Immunology and Genetic Program Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan.
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