A study on the function of cell-cycle specific inhibitor, CDT

细胞周期特异性抑制剂CDT的功能研究

• 批准号: 12470064
• 负责人: SUGAI Motoyuki
• 金额: $ 9.15万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12470064/
• 关键词: Cytolethal distending toxin; ctinibacillus actinomycetemcomitams; CDTABC complex; lipoptrotein; apoptosis; 細胞膨化致死毒素; G2; Mブロック; Actinobacillus actinomycetemcomitans; CDT; cell cycle; 毒素; 歯周病; 細胞周期

CDT from Actinobacillus actinomycetemcomitans (A.a) is composed of CDTA, B, and C encoded as cdtA, cdtB and cdtC genes tandemly-located on the chromosomal cdt locus. Immunoprecipitation study indicates that CDT forms complex. N-terminal sequencing of purified CDT revealed that 36-43 amino acids of CDTA are further processed at N-terminus probably after lipidmodification of CDTA. Sucrose density gradient ultracentrifuge showed the localization of CDT complex at the outer membrane. Taken together, we propose the hypothetical pathway of CDT secretion from periplasmic space to culture supernatant.CDT-induced death in T cell lines was accompanied with the biochemical features of apoptosis including membrane conformational change, intranucleosomal DNA cleavage, and increase of caspase activity in the cells. Inhibitors for caspase-2 and -7 showed significant inhibitory effect on CDT-induced apoptosis of Jurkat cells suggesting that CDT possesses an ability to induce human T cell apoptosis through activation of caspase-2 and -7.Among 45 A.a clinical isolates, CDT activity was found in cell lysate and culture supernatant of all tested strains, but the titer of the toxin in culture supernatant considerably varied among strains. PCR experiments indicated the presence of Y4-type cdt sequences in forty strains, suggesting that CDT production is prevalent in A.a strains.

来自放线菌（放线菌）的CDT由CDTA、B和C组成，编码为CDTA、cdtB和cdtC基因，并位于染色体CDT位点上。免疫沉淀研究表明CDT形成复合物。纯化CDT的n端测序结果显示，CDTA的36-43个氨基酸可能在脂质修饰后在n端进一步加工。蔗糖密度梯度超离心显示CDT复合物位于外膜。综上所述，我们提出了CDT从质周空间分泌到培养上清的假设途径。cdt诱导的T细胞系死亡伴随着细胞凋亡的生化特征，包括膜构象改变、核内体DNA分裂和细胞内caspase活性升高。caspase-2和-7抑制剂对CDT诱导的Jurkat细胞凋亡有显著抑制作用，提示CDT具有通过激活caspase-2和-7诱导人T细胞凋亡的能力。在45株A.a临床分离株中，所有菌株的细胞裂解液和培养上清液中均发现CDT活性，但培养上清液中毒素的滴度在菌株之间存在较大差异。PCR实验表明，在40株菌株中存在y4型cdt序列，表明A.a菌株普遍产生cdt。

项目成果

小原勝: "細菌毒素ハンドブック"桜井純, 本田武司, 小熊恵二. 7 (2002)

大原胜：“细菌毒素手册”Jun Sakurai、Takeshi Honda、Keiji Oguma 7 (2002)。

Masaru Ohara et al.: "Handbook on bacterial toxin Jun Sakurai, Takeshi Honda, Keiji Koguma eds"23-29 (2002)

Masaru Ohara 等：“细菌毒素手册 Jun Sakurai、Takeshi Honda、Keiji Koguma eds”23-29 (2002)

Ryousuke Yamano et al.: "Prevalence of cytolethal distending toxin production in period on topathogenic bacteria"J. Clin. Microbiol. Vol.41(In press). (2003)

Ryousuke Yamano 等人：“致病菌期间细胞致死膨胀毒素产生的流行率”J。

Ryousuke Yamano: "Prevalence of cytolethal distending toxin production in periodontopathogenic bacteria"J. Clin. Microbiol. 41(In press). (2003)

Ryousuke Yamano：“牙周致病菌中细胞致死膨胀毒素产生的流行率”J。