Peroxiredoxin I (Prx-I), a key member of the peroxiredoxin family, reduces peroxides and equiva- lents through the thioredoxin system. Our previous work has shown that expression of Prx-I in mammalian cells increases following ionizing radiation (IR), indicating that Prx-I actively responds to IR-induced reactive oxygen species (ROS) and suggesting that Prx-I plays an important role in protecting cells from IR-induced death. To test this hypothesis, we suppressed the expression of Prx-I in SW480 cells by RNA interference. Our results show that IR induces the expression of Prx-I in SW480 cells in a dose- and time- dependent manner. The recombinant siRNA vector targeting Prx-I dramatically reduced the expression of Prx-I in SW480 cells. When Prx-I was knocked down in SW480 cells, the cells exhibited a decreased growth rate, a reduced antioxidant capability following IR and became more sensitive to IR-induced apo- ptosis. Together, our results demonstrate that Prx-I plays an important role in protecting cells from IR- induced cell death, which might be through scavenging IR-induced ROS in the cells.

AIM: To clone and express mouse peroxiredoxin I in IEC-6 cells. METHODS: Total RNAs were isolated from cultured IEC-6 cells, and the coding region of peroxiredoxin I was amplified by RT-PCR. After it was cloned into T-vector and sequenced, pSG5 was used to transiently express peroxiredoxin I in IEC-6 by liposome-mediated transfection, and the expression of peroxiredoxin I was evaluated by RT-PCR and Western blot. RESULTS: A DNA fragment about 750 bp was amplified from total RNAs of IEC-6 cells using specific primers of peroxiredoxin I. The sequencing confirmed the coding region was successfully cloned into T-vector, which was completely coincident with the sequence in GeneBank. After the EcoRI-BamHI fragment of T-vector containing peroxiredoxin I was inserted into pSG5, the recombinant plasmid was transferred to IEC-6 cells. RT-PCR assay showed that a DNA fragment of 930 bp could be amplified, which indicated the transcription of pSG5-Prx. Western blot confirmed the expression of peroxiredoxin I in IEC-6 cells. CONCLUSION: Mouse peroxiredoxin I can be successfully expressed in IEC-6 cells.

Objective: To investigate the effect of Calpain inhibitor I on glucoconicoid receptor-dependent proteasomal degradation and its transcriptional activity. Methods: After Raw-264.7 cells were treated with Calpain inhibitor I, dexam- ethasone. or both for about 12 h. the change of glucocorticoid receptor was detected by westem blot analysis. COS. -7 cells were transfected with PRsh-GRa expression vector and glucocorticoid-responsive receptor pMAMneo-CAT, then the effect of Calpain inhibitor I on glucocorticoid receptor transcriptional activation ability was detennined by CAT activity. Results: The glucocorticoid receptor levels decreased after RAW-264.7 cells were treated with dexamethasone for 12 hours. which effect can be inhibited by Calpain inhibitor I to some extent. CAT activity assay showed that Calpain inhibitor I enhance glucoconi- coid receptor transcriptional activity. Condusion: Calpain inhibitor I can inhibit the down-regulation of dexamethasone on glucocorticoid receptor, and enhances glucocorticoid receptor transactivation ability.

AIM: To identify the differentially expressed proteins involved in ionizing radiation in mice and to explore new ways forstudying radiation-related proteins.

Preliminaryexperimentsindicatedthattargetcellswereresistanttoglucocorticoid(GC)afterpathologicalstress.Thisstudywasdesigned to investigate the alterations in plasma corticosterone level and GC receptor (GR) of liver cytosols, to assess the relative inflammatory cytokines contribution to GC resistant, and to observe the action of-melanocyte-stimulating hormone (-MSH) on the potential impli-cations of glucocorticord regulatory effects in burned rats. Male Wistar rats (weight range, 180-200g) received a 35% total body surface area immersion scald and were randomly divided to receive either tumor necrosis factor (TNF), interleukin-1 (IL-1), polyclonal antibody(pAb),-MSH,Ac-D-Lys-L-Pro-D-Val(KPVpeptide),orsaline(control).Thebindingcapacity(Rt)ofthesteroid-bindingsites Preliminary experiments indicated that target cells were resistant to glucocorticoid (GC) after pathological stress. This study was designed to investigate the alterations in plasma corticosterone level and GC receptor (GR) of liver cytosols, to assess the relative inflammatory cytokines contribution to GC resistant. and to observe the action of a-melanocyte-stimulating hormone (a-MSH) on the potential impli- cations of glucocorticord regulatory effects in burned rats. Male Wistar rats (weight range, 1 80-200 g) received a 3 5% total body surface area immersion scald and were randomly divided to receive either tumor necrosis factor a (TNFa), interleukin-l [3 (11-1 [3), polyclonal antibody (pAb), a-MSH. Ac-D-Lys-L-Pro-D-Val (KPV peptide), or saline (controD.The binding capacity (Rt) of the steroid-binding sites was measured by radioligand binding assay, using [3H]dexamethasone as the ligand. We examined plasma levels of 11-1 [3, TNFa, IL-10, and corticosterone following scald challenge in rats. The Rt of GR (208.45

Peroxiredoxin I (Ptx I) is involved in many important cellular progresses such as cell proliferation and differentiation. To further elucidate its roles in ionizing radiation, eukaryotic expression vector containing siRNA targeting mRNA of peroxiredoxin 1 gene was constructed and transected into NIH3T3 cell line following sequencing.Westem blot analysis showed that this siRNA significantly inhibited Prx I expression roy 65 0-10 at protein level; cell proliferation experiment demonstrated that the double proliferation time of NIH 3T3Prx I cells was postponed for 1.8 hours as compared with control group. MTT results showed that 12 and 48 hours after irradiation the survival rate of NIH 3T3P was dramatically decreased when comparing with sham-irradiated group. These results suggested that peroxiredoxin 1 has radiation-cytoprotection role.

随着基因组测序工程的实施与完成，如何对包含完整基因信息的特定细菌人工染色体（BAC）进行有目的修饰，已成为功能基因组学研究的一个重要环节。应用新近优化的Red/ET同源重组技术对目标BAC进行修饰，以pSClOI-BAD-gbaA为依托质粒，采用rpsL-ne。为正/反向筛选系统，可以快速、高效地对BAC进行剪切、插入、替换等操作，其中能够进行抗性筛选的一步BAC修饰只需一周时间，以插入非抗性标记基因Cre为代表的两步BAC修饰在两周内即可完成。通过阿拉伯多糖诱导调控和简单地变化培养温度，能使pSClOI-BAD-gbaA依托质粒在发挥完Red/ET同源重组作用后自然消失，最终获得完整而纯净的修饰后BAC，为加快功能基因组学研究提供了一个可靠的实验平台

目的繁殖和鉴定SRC-3基因敲除小鼠。方法将所引进的杂合子小鼠进行饲养并繁殖，繁殖成功后其子代中将会出现野生型、杂合子以及纯合子3种基因型，提取每只小鼠尾部基因组DNA，用PCR法进行鉴定，一旦获得雄性纯合子，就将其与雌性杂合子交配，依照孟德尔遗传定律就有可能获得较多的基因敲除纯合子小鼠。结果SRC-3杂合子小鼠的饲养和繁殖均获得成功，亦获得了较多的基因敲除纯合子小鼠。结论正确的饲养繁殖以及鉴定方法是从杂合子中获得SRC-3基因敲除纯合子小鼠的有效途径。

目的研究小鼠严重闭合性脑创伤后外周血中白细胞介素ip（IL- ip）、肿瘤坏死因子a（TNF-a）的变化与肝脏糖皮质激素受体（GR）变化的关系。方法利用BIM-Ⅲ型小型多功能动物撞击机对小鼠清醒致伤，于致伤后30 min、2h、8h、24 h、48 h、72 h采用酶联免疫吸附法（EIISA）检测各组外周血清中细胞因子的含量，放免法检测皮质醇含量，WesLem Blot免疫印迹法检测肝脏CR的蛋白水平的变化。结果致伤后外周血中TNF-a、IL-1B、皮质醇较对照组有明显升高，均具有两个峰值特征；GR在致伤2h后开始出现蛋白水平表达降低，72 h仍未完全恢复正常。结论严重颅脑外伤后外周组织存在糖皮质激素抵抗，与TWF-a、IL-1β关系密切。

目的研究贫铀（DU）弹片嵌入软组织后，铀在机体内的分布、动态变化，以及取片对铀浓度的影响。方法将DU片植入大鼠肌肉，取片组在植入后第5天取出DU片，在植入后第1，3，7，15，20，26天收集样本，预处理，用激光荧光法测定铀含量。结果植入DU大鼠所有样本铀浓度均显著高于正常对照组，尤其是肾脏、卵巢和胸骨铀浓度更高；单片组植片部位的肌肉铀浓度远高于未植片部位，其余组织铀浓度显著高于取片组。结论植入DU片大鼠体内铀分布的主要器官是肾脏、卵巢和胸骨；取出嵌入的贫铀片可大大减少组织内的铀浓度，同时应剪去周围的肌肉组织。