Zhao S L, Zhao F, Li Q, Zhang J, Zhang Z W, Li C D, Liu P N, Tong W M, Niu Y M
Department of Pathology, Institute of Basic Medical Sciences Chinese Academy of Medical Science, School of Basic Medicine, Peking Union Medical College; Molecular Pathology Center, Chinese Academy of Medical Sciences, Beijing 100005, China.
Department of Neurosurgery, Tiantan Hospital, Capital Medical University, Beijing 100050, China.
Zhonghua Bing Li Xue Za Zhi. 2019 Sep 8;48(9):694-699. doi: 10.3760/cma.j.issn.0529-5807.2019.09.006.
To investigate the expression and potential role of heterogeneous nuclear ribonucleo-protein A2B1 (HNRNPA2B1) in mouse cerebellar development and the significance of HNRNPA2B1 in human medulloblastoma. The data of HNRNPA2B1 RNA expression in mouse and human cerebella were obtained from databases. Western blot and immunohistochemical staining were performed to detect the protein level of HNRNPA2B1 in mouse cerebella at different ages. The expression level of HNRNPA2B1 in control human cerebellum and medulloblastoma was detected by immunohistochemical staining. m6A-IP-qPCR method was applied to confirm whether HNRNPA2B1 RNA in Daoy cells was modified with m6A.Western blot was used to detect the effect of MG132 treatment on the HNRNPA2B1 protein level in Daoy cells. The level of HNRNPA2B1 protein in postnatal mouse cerebella was higher than that in adult mouse cerebella, with weak HNRNPA2B1 staining in external granular cells while strong staining in mature Purkinje cells and molecular layer. Compared with control normal human cerebella, the RNA expression level of HNRNPA2B1 increased in medulloblastoma, while immunohistochemical staining showed that the mean intensity of HNRNPA2B1 decreased in medulloblastoma. HNRNPA2B1 RNA in medulloblastoma and Daoy cells was modified by m6A. The HNRNPA2B1 protein level in Daoy cells increased upon MG132 treatment. HNRNPA2B1 is dynamically expressed during mouse cerebellar development. Compared with normal human cerebella, HNRNPA2B1 is significantly up-regulated at transcriptional level but obviously down-regulated at translational level in medulloblastoma. These results indicate that HNRNPA2B1 may be involved in cerebellar development process and medulloblastoma tumorigenesis. The m6A methylation in HNRNPA2B1 transcript and protein ubiquitin-proteasome pathway may account for the down-regulation of HNRNPA2B1 at protein level.
研究异质性核核糖核蛋白A2B1（HNRNPA2B1）在小鼠小脑发育中的表达及潜在作用，以及HNRNPA2B1在人类髓母细胞瘤中的意义。从小鼠和人类小脑的数据库中获取HNRNPA2B1 RNA表达数据。采用蛋白质免疫印迹法和免疫组织化学染色法检测不同年龄小鼠小脑中HNRNPA2B1的蛋白水平。通过免疫组织化学染色检测对照人类小脑和髓母细胞瘤中HNRNPA2B1的表达水平。应用m6A-IP-qPCR方法确认道氏（Daoy）细胞中的HNRNPA2B1 RNA是否被m6A修饰。采用蛋白质免疫印迹法检测MG132处理对道氏细胞中HNRNPA2B1蛋白水平的影响。出生后小鼠小脑中HNRNPA2B1蛋白水平高于成年小鼠小脑，外颗粒细胞中HNRNPA2B1染色较弱，而成熟浦肯野细胞和分子层中染色较强。与对照正常人类小脑相比，髓母细胞瘤中HNRNPA2B1的RNA表达水平升高，而免疫组织化学染色显示髓母细胞瘤中HNRNPA2B1的平均强度降低。髓母细胞瘤和道氏细胞中的HNRNPA2B1 RNA被m6A修饰。MG132处理后道氏细胞中HNRNPA2B1蛋白水平升高。HNRNPA2B1在小鼠小脑发育过程中动态表达。与正常人类小脑相比，HNRNPA2B1在髓母细胞瘤中在转录水平显著上调，但在翻译水平明显下调。这些结果表明，HNRNPA2B1可能参与小脑发育过程和髓母细胞瘤的肿瘤发生。HNRNPA2B1转录本中的m6A甲基化和蛋白质泛素-蛋白酶体途径可能是HNRNPA2B1蛋白水平下调的原因。
