| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
The HuC/ple2l neural protein is an autoantigen for anti-neuronal nuclear autoantibodies from a patient with paraneoplastic neurologic syndromes and small cell lung carcinoma. (1) To investigate the influences of the autoantibodies on the biological function of the antigen, we mapped the regions which were required for the antibody recognition and for the RNA binding. Deletion analysis of the antigen revealed that the epitopes for the antibodies were localized in the regions of 12 residues, amino acids 161-172, and 8 residues, amino acids 29-38, of the first and second RRMs. We identified that the 8 residues, amino acids 29-38, and the 10 residues, amino acids 187-194, were required for the RNA binding. Although amino acids 29-38 were necessary for both the antibody recognition and the RNA bindings, pre-incubation of the PLE21 antigen with the antibodies did not inhibit the formation of the complex of PLE 21, the antibodies and RNA.(2) The study was designed to examine the potential contributions of the first two RRMs to binding to a cytokine mRNA.Studies with deletion mutants of HuC/ple2l indicated that the octapeptide amino acids 187-194, of RRM2 can be compensated for the binding function of RRM2. It was also shown that the substitutions of glutamic acid at 42 for aspartic acid and leucine at 44 for phenylalanine in the first potent alpha-helix structure of RRM1, as were seen in another ELAV-like protein Hel-N1, markedly affect the RNA binding. (3) We also demonstrated that HuC/ple2l binds to the ARE in 3'-UTR of TNF-alpha mRNA, and that treatment of neuroblastoma cells in vitro with interleukin-4 reduced the expression of the neuronal ELAV-like proteins. These evidences suggest that the expression of the neuronal ELAV-like proteins may be closely associated with the expression of TNF-alpha in neuronal cells.
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