Nuclear interactions of retinoic acid-binding protein in chemically induced mammary adenocarcinoma.
Nuclear interactions of retinoic acid-binding protein in chemically induced mammary adenocarcinoma.
复制标题
化学诱导的乳腺癌中视黄酸结合蛋白的核相互作用。
作者：
R. Mehta;W. L. Cerny;R. Moon
细胞视黄酸结合蛋白（CRABP）检测后，在N-甲基-N-亚硝基脲诱导的乳腺癌的细胞核部分孵育的胞浆含有[3 H]视黄酸（RA）结合的CRABP与分离的细胞核。CRABP从细胞核中提取的缓冲液含有0.4 M-氯化钾沉淀作为2 S组分时，进行蔗糖密度梯度分析。发现[3 H]RA-CRABP是检测核结合的先决条件，因为分离的细胞核或细胞核的0.4 M-KCl提取物与[3 H]RA的孵育未导致任何显著结合。与0 ℃孵育相比，[3 H]RA-CRABP在与细胞核孵育之前在25或30 ℃孵育既不改变沉降系数也不增强细胞核结合。肿瘤细胞核含有饱和数量的结合位点，解离常数为1.6 × 10（-9）M。这些结果表明，视黄酸在靶器官中的作用可能是通过其与核的相互作用介导的。
Cellular retinoic acid-binding protein (CRABP) was detected in the nuclear fraction of N-methyl-N-nitrosourea-induced mammary cancers after the incubation of cytosol containing [3H]retinoic acid (RA)-bound CRABP with isolated nuclei. CRABP extracted from the nuclei in buffer containing 0.4 M-KCl sedimented as a 2 S component when subjected to sucrose-density-gradient analysis. [3H]RA-CRABP was found to be a prerequisite for the detection of nuclear binding, since the incubation of isolated nuclei or 0.4 M-KCl extract of the nuclei with [3H]RA did not result in any significant binding. Incubation of [3H]RA-CRABP at 25 or 30 degrees C before incubation with the nuclei neither altered the sedimentation coefficient nor enhanced the nuclear binding compared with 0 degrees C incubation. The tumour nuclei contained a saturable number of binding sites with a dissociation constant of 1.6 x 10(-9) M. These results indicate that the action of retinoic acid in the target organ may be mediated by its interaction with the nuclei.