Rakowicz-Szulczynska E M, Otwiaska D, Koprowski H
Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania 19104.
Mol Carcinog. 1990;3(3):150-6. doi: 10.1002/mc.2940030308.
Analysis of different cellular fractions after incubation of SW 948 and SW 707 colorectal carcinoma cells or WM 266-4 melanoma cells with 125I-insulin revealed the nondegraded hormone in the chromatin of these cells. Nuclear 125I-insulin was bound to specific fragments of EcoRI-, HaeIII-, and HincII-digested chromatin. A 45-kDa chromatin protein species that binds 125I-insulin was identified. Actinomycin D and cycloheximide inhibited the insulin-stimulated expression of chromatin receptors. Uptake of 125I-insulin by isolated nuclei occurred only in the presence of plasma membranes. Thus, at least some effects of insulin on target cells can be explained by direct gene regulation instead of "second messenger" action.
用¹²⁵I-胰岛素孵育SW 948和SW 707结肠癌细胞或WM 266-4黑色素瘤细胞后，对不同细胞组分进行分析，结果显示这些细胞的染色质中存在未降解的激素。细胞核中的¹²⁵I-胰岛素与经EcoRI、HaeIII和HincII消化的染色质的特定片段结合。鉴定出一种结合¹²⁵I-胰岛素的45 kDa染色质蛋白。放线菌素D和环己酰亚胺抑制胰岛素刺激的染色质受体表达。分离的细胞核对¹²⁵I-胰岛素的摄取仅在有质膜存在时发生。因此，胰岛素对靶细胞的至少某些作用可以通过直接基因调控而非“第二信使”作用来解释。
