Comolli R, Bardella L
Cancer Biochem Biophys. 1982;6(2):119-24.
Eukaryotic initiation factor 2 (eIF-2) preparations from mid-log and plateau-phase Yoshida ascites hepatoma AH 130 cells, from the liver of Yoshida ascites tumor-bearing rats and from 4-dimethylaminoazobenzene (DAB)-induced liver tumor tissue were assayed for ternary complex formation with 3H-met-tRNAf and GTP on nitrocellulose filters. The eIF-2 factor was extracted from postnuclear homogenate supernatants by high-salt wash and purified by ion exchange chromatography on DEAE-cellulose and phosphocellulose. The results here reported demonstrate changes of 3H-met-tRNAf X eIF-2 X GTP ternary complex formation under the conditions studied. Higher rates of ternary complex formation are present in control rat liver and in DAB-induced liver tumor tissue. The liver of Yoshida ascites tumor-bearing rats and the Yoshida ascites hepatoma cells show reduced rates of ternary complex formation, that are mostly evident at the plateau-phase of the intraperitoneal ascites cell growth. The present observations may be attributable to changes in the growing conditions of plateau-phase ascites cells, with accumulation in Gl phase, affecting the ability of eIF-2 to enter in the sequential assembly of the eukaryotic protein synthesis initiation complex.
采用硝酸纤维素滤膜法，对处于对数中期和平台期的吉田腹水肝癌AH 130细胞、荷吉田腹水瘤大鼠的肝脏以及4-二甲基氨基偶氮苯（DAB）诱导的肝肿瘤组织中的真核起始因子2（eIF-2）制剂与³H-甲硫氨酰-tRNAf和GTP形成三元复合物的能力进行了检测。eIF-2因子通过高盐洗涤从核后匀浆上清液中提取，并经DEAE-纤维素和磷酸纤维素离子交换色谱法纯化。本文报道的结果表明，在所研究的条件下，³H-甲硫氨酰-tRNAf·eIF-2·GTP三元复合物的形成发生了变化。对照大鼠肝脏和DAB诱导的肝肿瘤组织中三元复合物的形成率较高。荷吉田腹水瘤大鼠的肝脏和吉田腹水肝癌细胞中三元复合物的形成率降低，这在腹腔腹水细胞生长的平台期最为明显。目前的观察结果可能归因于平台期腹水细胞生长条件的变化，细胞在G1期积累，影响了eIF-2参与真核蛋白质合成起始复合物顺序组装的能力。
