Lin D, Shields M T, Ullrich S J, Appella E, Mercer W E
Department of Microbiology and Immunology, Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107.
Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):9210-4. doi: 10.1073/pnas.89.19.9210.
Conditional expression of wild-type (wt) p53 protein in a glioblastoma tumor cell line has been shown to be growth inhibitory. We have now more precisely localized the position in the cell cycle where growth arrest occurs. We show that growth arrest occurs prior to or near the restriction point in late G1 phase of the cell cycle. The effect of wt p53 protein on the expression of four immediate-early genes (c-FOS, c-JUN, JUN-B, and c-MYC), one delayed-early gene (ornithine decarboxylase), and two late-G1/S-phase genes (B-MYB and DNA polymerase alpha) was also examined. Of this subset of growth response genes, only the expression of B-MYB and DNA polymerase alpha was significantly repressed. The possibility that decreased expression of B-MYB may be an important component of growth arrest mediated by wt p53 protein is discussed.
野生型（wt）p53蛋白在胶质母细胞瘤肿瘤细胞系中的条件性表达已被证明具有生长抑制作用。我们现在更精确地定位了细胞周期中生长停滞发生的位置。我们发现生长停滞发生在细胞周期G1期晚期的限制点之前或附近。我们还研究了wt p53蛋白对四个立即早期基因（c-FOS、c-JUN、JUN-B和c-MYC）、一个延迟早期基因（鸟氨酸脱羧酶）以及两个G1/S期晚期基因（B-MYB和DNA聚合酶α）表达的影响。在这个生长反应基因子集中，只有B-MYB和DNA聚合酶α的表达受到显著抑制。文中讨论了B-MYB表达降低可能是wt p53蛋白介导的生长停滞的一个重要组成部分的可能性。
