Maraldi N M, Santi S, Zini N, Ognibene A, Rizzoli R, Mazzotti G, Di Primio R, Bareggi R, Bertagnolo V, Pagliarini C
Istituto di Citomorfologia Normale e Patologica del C.N.R., Istituto di Ricerca Codivilla-Putti, Bologna, Italy.
J Cell Sci. 1993 Mar;104 ( Pt 3):853-9. doi: 10.1242/jcs.104.3.853.
Lipid metabolism in nuclei is very active and appears involved in the transduction of signals to the genome in response to agonists acting at the plasma membrane level. However, the precise topology of nuclear lipid metabolism and the relationship between nuclear lipids and crucial events of the cell function, such as DNA replication, have not been fully elucidated. By using a recently developed cytochemical method for detecting phospholipids inside the nucleus of intact cells at the electron microscope level, we have analyzed the changes in intranuclear phospholipids in DNA-replicating versus resting cells, which are both present in the same sample of regenerating liver after partial hepatectomy. The pattern of DNA synthesis in replicating cells has been monitored by electron microscope immunocytochemistry after bromodeoxyuridine (BrdU) labeling. The data obtained, which allow a fine localization and a quantitative analysis of both DNA synthesis and phospholipid distribution, indicate a significant reduction in the phospholipids detectable inside the nucleus in all steps of the S phase. This could depend on an increased nuclear phospholipid hydrolysis, whose products should in turn activate some of the enzymes involved in the control of DNA replication.
细胞核中的脂质代谢非常活跃，似乎参与了在质膜水平上对激动剂作出反应时向基因组的信号转导。然而，核脂质代谢的确切拓扑结构以及核脂质与细胞功能的关键事件（如DNA复制）之间的关系尚未完全阐明。通过使用最近开发的一种细胞化学方法，在电子显微镜水平上检测完整细胞细胞核内的磷脂，我们分析了部分肝切除术后再生肝脏同一样本中DNA复制细胞与静止细胞内核内磷脂的变化。通过溴脱氧尿苷（BrdU）标记后，利用电子显微镜免疫细胞化学监测复制细胞中的DNA合成模式。所获得的数据能够对DNA合成和磷脂分布进行精细定位和定量分析，表明在S期的所有阶段，细胞核内可检测到的磷脂显著减少。这可能取决于核磷脂水解增加，其产物反过来又会激活一些参与DNA复制控制的酶。
