Overexpression of a dominant-negative ornithine decarboxylase in mouse skin: effect on enzyme activity and papilloma formation.
Overexpression of a dominant-negative ornithine decarboxylase in mouse skin: effect on enzyme activity and papilloma formation.
复制标题
小鼠皮肤中显性失活鸟氨酸脱羧酶的过度表达：对酶活性和乳头状瘤形成的影响。
DOI：
10.1093/carcin/23.4.657
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发表时间：
2002
期刊：
影响因子：
4.7
通讯作者：
O'Brien,ThomasG
中科院分区：
文献类型：
--
作者：
Shantz,LisaM;Guo,Yongjun;Sawicki,JanetA;Pegg,AnthonyE;O'Brien,ThomasG
已经建立了在角蛋白6启动子控制下表达截短形式的鸟氨酸脱羧酶（ODC）显性阴性突变体K69 A/C360 A的转基因小鼠系（K6/ODCdn小鼠）。将这些小鼠回交到DBA/2 J和C57 BL/6 J背景上，用于随后的利用起始/促进方案的肿瘤发生实验。在短期实验中，ODCdn蛋白产物的表达诱导后24小时内的表皮中应用的肿瘤促进剂十四酰基佛波醇乙酸酯（TPA）的皮肤，和ODC活性在表皮中的K6/ODCdn小鼠减少了至少75%，与同窝对照。然而，在使用各种引发剂（7，12-二甲基苯并[a]蒽; DMBA）和促进剂（TPA）浓度的肿瘤发生实验中，K6/ODCdn小鼠形成的肿瘤至少与其同窝对照小鼠一样多，而与背景菌株无关。在利用chrysarobin（一种作用机制与TPA不同的肿瘤促进剂）的实验中，K6/ODCdn小鼠和同窝对照小鼠之间的肿瘤形成也没有显著差异。类似地，当K6/ODCdn小鼠与K5/ODC小鼠（先前描述的在不应用促进剂的情况下形成肿瘤的转基因系）杂交时，双转基因小鼠形成与仅表达K5/ODC转基因的小鼠一样多的肿瘤。多次TPA应用后的表皮分析显示，在6次应用后，K6/ODCdn小鼠和非转基因小鼠中ODC活性急剧增加，并且蛋白质印迹分析表明K6/ODCdn转基因小鼠中内源性野生型ODC稳定。ODC活性，内源性蛋白质和多胺也从K6/ODCdn小鼠的肿瘤中升高。内源性ODC蛋白的积累最可能是转基因衍生的ODCdn蛋白竞争结合抗酶的结果，已知抗酶通过刺激ODC蛋白的降解来调节ODC活性。
A transgenic mouse line expressing a truncated form of the ornithine decarboxylase (ODC) dominant-negative mutant K69A/C360A under the control of the keratin 6 promoter has been established (K6/ODCdn mice). These mice were backcrossed onto both the DBA/2J and C57BL/6J backgrounds for subsequent tumorigenesis experiments utilizing an initiation/promotion protocol. In short-term experiments, expression of the ODCdn protein product was induced in the epidermis within 24 h after application of the tumor promoter tetradecanoyl phorbol acetate (TPA) to the skin, and ODC activity in the epidermis of K6/ODCdn mice was reduced by at least 75% compared with littermate controls. However, in tumorigenesis experiments utilizing a variety of initiator (7,12-dimethylbenz[a]anthracene; DMBA) and promoter (TPA) concentrations, K6/ODCdn mice formed at least as many tumors as their littermate controls regardless of background strain. In experiments utilizing chrysarobin, a tumor promoter with a different mechanism of action than TPA, again there was no significant difference in tumor formation between K6/ODCdn mice and littermate controls. Similarly, when K6/ODCdn mice were crossed with K5/ODC mice, a transgenic line described previously which forms tumors without application of a promoting agent, double transgenic mice formed as many tumors as mice expressing the K5/ODC transgene alone. Analysis of epidermis following multiple TPA applications revealed a dramatic spike in ODC activity in both K6/ODCdn mice and non-transgenic mice after six applications, and western blot analysis suggested a stabilization of endogenous wild-type ODC in K6/ODCdn transgenic mice. ODC activity, endogenous protein and polyamines were also elevated in tumors from K6/ODCdn mice. The accumulation of endogenous ODC protein is most probably the result of competition from the transgene-derived ODCdn protein for binding of antizyme, which is known to regulate ODC activity by stimulating degradation of the ODC protein.