第四届九源奖学金一等奖论文摘要（2）

4、Complete Nucleotide Sequence and Infectious cDNA Clone of the RNA1 of a Chinese Isolate of Broad Wilt Virus 2（发表刊物：Virus Genes 20:3, 201-207, 2000）

The nucleotide sequence of the RNA1 of broad bean wilt virus 2 (BBWV2) isolate B935 has been determined from overlapping cDNA clones. It contains 5956 nucleotides in length excluding the 3'terminal poly (A) tail and contains a single long open reading frame (ORF) of 5613 nucleotide 234 to 5846 .A repeated motif has been found in the 5'non-coding region .The predicted polyproteins encoded by the long ORF is 1870 amino acid in length with a molecular weight of 210K, Amino acid sequence comparisons between portions of the BBWV2 RNSA1-encoded polyprotein an proteins encoded by several species in Comoviridae revealed the putative functions of BBWV2 RNA1-encoded proteins and the same general genetic organization as that of comoviruses and nepoviruses. Based on the determined sequence, full-length cDNA clone of RNA1 designated as pU1FL was constructed. Together with transcripts from full-length cDNA clone of RNA2 (pU2FL), transcripts from pU1FL infected Chenopodium quinoa successfully.

作者：戚益军（浙江大学生物技术研究所，分子生物学专业博士，导师：李德葆教授）

5、Heterologous Activation of Protein Kinase C Stimulates Phosphorylation of δ Opioid Receptor at Serine 344 and This Results in beta-arrestin- and Clathrin-mediated Receptor Internalization （发表刊物：Journal of Biological Chemistry / jbc. M006187200）

The current study is to investigate the effect of opioid-independent, heterologous activation of PKC on the responsiveness of opioid receptor and the underlying molecular mechanisms. Our result showed that removing the C-terminus of δ-opioid receptor (DOR) containing six Ser/Thr residues abolished both DPDPE-and PMA-induced DOR phosphorylation, The phosphorylation levels of DOR mutant T352A, T353A, T358A/T361A/S363S were comparable to that of the wild-type DOR whereas S344A substitution blocked PMA-induced receptor phosphorylatoin occurs at S344. PKC-mediated S344 phosphorylation was also induced by activation of Gq coupled α1A-adrenergic receptor or increase in intracellular Ca2+ concentration. Activation if PKC by PMA, ?1A-adrenergic receptor agonist, and ionomycin resulted in Dor internalization that required phosphorylation of S344. Expression of domain negative β-arrestin and hypertonic sucrose treatment blocked PMA-induced DOR internalization, suggesting that PKC mediates DOR internalization via a β-arrestin-and clathrin-dependent mechanism. Further study demonstrated that agonist-dependent GRK-mediated receptor phosphorylation and agonist-independent, PKC-mediated DOR phosphorylation were addictive, but agonist-induced receptor phosphorylation could inhibit PKC-catalyzed heterologous DOR phosphorylatinon and subsequent internalization. These data demonstrate that the responsiveness of opioid receptor id regulated by both PKC and GRK through agonist-dependent and agonist-independent and agonist-independent mechanisms and PKC-mediated receptor phosphorylation is an important molecular mechanism of heterologous regulation of opioid receptor functions.

作者：向斌（复旦大学医学院神经生物学国家重点实验室，神经生物学博士，导师：马兰教授）

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