Slug is a transcription factor belonging to the slug/snail superfamily. The protein is involved in embryonic development and epithelial-mesenchymal transition of tumors. Slug is also under temporal regulation during cell cycle. Here, we examined relationship between pSlug^S158 (site-specific phosphorylation) and the cell cycle, and checked whether its phosphorylation level reflects mitotic activity in tissue specimens. Cell cycle analysis was performed after cell synchronization. To evaluate pSlug^S158 identifying mitotic figures, we performed immunohistochemistry (IHC) for pSlug^S158 in various formalin-fixed paraffin-embedded tissues; in addition, mitotic counts were compared with those in sections stained with hematoxylin and eosin (HE) and IHC for PHH3, a mitotic marker. We found that the level of pSlug^S158 protein increased specifically at M phase and decreased at the G1/S phases in vitro. In almost all tested tissues, nuclear stain of pSlug^S158 was identified in the cell with mitotic figures. There was no significant difference in mitotic counts between HE- and pSlug^S158-stained sections. In conclusion, pSlug^S158 may be a novel and practical immunohistochemical marker for detecting mitotic figures in human tissues.

蛞蝓是属于蛞蝓/蜗牛超家族的转录因子。该蛋白参与肿瘤的胚胎发育和上皮间质转化。在细胞周期中，蛞蝓也处于时间调节之下。在这里，我们检查了 pSlug ^S158（位点特异性磷酸化）与细胞周期之间的关系，并检查了其磷酸化水平是否反映了组织标本中的有丝分裂活性。在细胞同步后进行细胞周期分析。为了评估 pSlug ^{S158识别有丝分裂图，我们对 pSlug S158}进行了免疫组织化学 (IHC)在各种福尔马林固定的石蜡包埋组织中；此外，将有丝分裂计数与用苏木精和伊红 (HE) 和 IHC 染色的切片中的有丝分裂计数进行比较，PHH3 是一种有丝分裂标志物。我们发现 pSlug ^S158蛋白的水平在 M 期特异性增加，在体外 G1/S 期降低。在几乎所有测试的组织中，pSlug ^S158的核染色在有丝分裂图的细胞中被发现。HE 和 pSlug ^S158染色切片之间的有丝分裂计数没有显着差异。总之，pSlug ^S158可能是一种新颖实用的免疫组化标记物，用于检测人体组织中的有丝分裂图。