Distinct mode of microtubule-associated protein 2 expression in the neuroblastoma/glioma cell line 108CC15/NG108-15.
Distinct mode of microtubule-associated protein 2 expression in the neuroblastoma/glioma cell line 108CC15/NG108-15.
复制标题
神经母细胞瘤/神经胶质瘤细胞系 108CC15/NG108-15 中微管相关蛋白 2 表达的独特模式。
DOI：
10.1002/neu.480241105
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Vallano,ML
中科院分区：
文献类型：
--
作者：
Beaman-Hall,CM;Vallano,ML
The properties of microtubule‐associated protein‐2 (MAP‐2) expression were examined in a transformed cell line, and compared to neurons from rodent brain where evidence supports both transcriptional and nontranscriptional regulation of MAP‐2 synthesis. A monoclonal antibody that recognizes a common epitope in the adult (HMW MAP‐2) and juvenile (MAP‐2c) forms was used in an immunoblotting assay to assess the protein levels in actively dividing and differentiated neuroblastoma/glioma (108CC15, also designated NG108‐15) cells. Multiply‐phosphorylated MAP‐2c was the predominant form in actively dividing cells, whereas HMW MAP‐2 predominated in differentiated cells, which exhibited several other neuronal‐like properties. A progressive increase in the levels of immunoreactive HMW MAP‐2 was observed with increasing days of cell differentiation using dBcAMP as the inducing agent. However, the absolute levels of both HMW MAP‐2 and MAP‐2c in NG108‐15 cells were significantly lower (at least 10‐fold) than levels measured in rodent brain. To assess whether there are correspondingly lower levels of HMW MAP‐2 and MAP‐2c mRNAs in NG108‐15 cells, relative to rodent brain, a highly sensitive RNA amplification assay (reverse transcription‐polymerase chain reaction; RT‐PCR) was developed. Oligonucleotide primers were designed to specify either HMW MAP‐2 mRNA or MAP‐2c mRNA, and whole tissue RNA extracted from adult and neonatal rodent brain was used to verify the reliability of the RT‐PCR assay. Accordingly, PCR products of the predicted size, specificity, and abundance were obtained, with similar levels of HMW MAP‐2 mRNA and proportionately higher levels of MAP‐2c mRNA in neonatal brain, relative to adult brain. MAP‐2c mRNA was the predominant transcript in actively dividing NG108‐15 cells, and the amount of HMW MAP‐2 mRNA gradually increased and became the predominant transcript in cells exposed to dBcAMP for 6–9 days. Thus, the observed changes in MAP‐2‐specific mRNAs during differentiation paralleled changes in expressed protein, suggesting that MAP‐2 synthesis in NG108y15 cells is transcriptionally controlled. However, the levels of both MAP‐2 mRNAs in NG108‐15 cells were comparable to levels in rodent brain, despite the fact that MAP‐2 protein levels are at least 10‐fold lower in NG108‐15 cells. These data suggest that the low levels of HMW MAP‐2 and MAP‐2c protein expression in NG108‐15 cells are not due to correspondingly lower levels of MAP‐2 mRNAs, and that transformed neuronal cell lines demostrate a unique mode of MAP‐2 regulation. © 1993 John Wiley & Sons, Inc.
