非洲爪蟾卵母细胞中的165千道尔顿DNA拓扑异构酶I是一种组织特异性变体。

The 165-kDa DNA topoisomerase I from Xenopus laevis oocytes is a tissue-specific variant.

作者信息

Richard R E, Bogenhagen D F

机构信息

Department of Pharmacological Sciences, State University of New York, Stony Brook 11794.

出版信息

Dev Biol. 1991 Jul;146(1):4-11. doi: 10.1016/0012-1606(91)90441-5.

DOI:10.1016/0012-1606(91)90441-5

PMID:1647991

Abstract

Two forms of topoisomerase I can be purified from Xenopus laevis. A protein with a molecular mass of 165 kDa has been identified as topoisomerase I in ovaries (Richard and Bogenhagen, 1989. J. Biol. Chem. 264, 4704-4709). When a similar purification is performed using liver tissue, topoisomerase I is purified as a 110-kDa protein. Separate rabbit antisera were raised against oocyte and liver topoisomerase I polypeptides. Each antiserum reacts in immunoblotting or immunoprecipitation procedures only with the tissue-specific topoisomerase I polypeptide against which it was generated. The failure of the antiserum raised against liver topoisomerase I to cross-react with the oocyte enzyme suggests that the smaller topoisomerase I is not derived from the 165-kDa oocyte enzyme by proteolysis. X. laevis tissue culture cells lysed and processed in the presence of SDS contain the 110-kDa form of topoisomerase I. The 165-kDa form of topoisomerase I disappears during oocyte maturation in vitro.

摘要

可以从非洲爪蟾中纯化出两种形式的拓扑异构酶I。在卵巢中，一种分子量为165 kDa的蛋白质已被鉴定为拓扑异构酶I（Richard和Bogenhagen，1989。《生物化学杂志》264，4704 - 4709）。当使用肝脏组织进行类似的纯化时，拓扑异构酶I被纯化为一种110 kDa的蛋白质。分别制备了针对卵母细胞和肝脏拓扑异构酶I多肽的兔抗血清。每种抗血清在免疫印迹或免疫沉淀实验中仅与产生它的组织特异性拓扑异构酶I多肽发生反应。针对肝脏拓扑异构酶I产生的抗血清不能与卵母细胞酶发生交叉反应，这表明较小的拓扑异构酶I并非由165 kDa的卵母细胞酶经蛋白水解产生。在SDS存在下裂解并处理的非洲爪蟾组织培养细胞含有110 kDa形式的拓扑异构酶I。165 kDa形式的拓扑异构酶I在体外卵母细胞成熟过程中消失。