中文摘要：

目的：研究LRRC4基因在恶性脑胶质瘤细胞系中的表达情况。方法：采用RT-PCR结合Northern-blot检测LRRC4基因在U251,U87,SF126,SF767,BT325及M17等6种恶性脑胶质瘤细胞系中的表达;并应用聚合酶链反应结合DNA直接测序法检测LRRC4基因在恶性胶质瘤细胞系中的突变情况;进一步结合生物信息学分析研究LRRC4基因在U251细胞系中表达缺失的原因。结果：LRRC4基因在6种恶性胶质瘤细胞系中均表达缺失。通过对胶质瘤细胞系基因组DNA中LRRC4的ORF序列的PCR扩增和测序分析,发现SF126,SF767,M17细胞中,ORF序列第279位氨基酸的第3个密码子存在同义点突变（3/5）,而U251和U87细胞基因组DNA中发生了LRRC4基因的缺失突变（2/5）。结论：LRRC4基因在恶性胶质瘤细胞中表达缺失,染色体7q32-ter的纯合性缺失是LRRC4基因在U251细胞中表达缺失的原因。

英文摘要：

Objective To examine the expression absence of LRRC4 gene in glioblastoma cell lines. Methods RT-PCR and Northern blot were used to detect the expression of LRRC4 gene in 6 glioblastomas cells lines. Polymerase chain reaction and DNA sequencing were used to screen the LRRC4 gene mutation, while bioinformation assay was used to search for the reason of LRRC4 gene absence in U251 cell lines. Results The expression of LRRC4 was absent in 6 malignant glioma cell lines （U251, U87, BT325, SF126, SF767 and M17） , which were examined by Northernblot and RT-PCR assay. All sequencing of PCR products from gDNA of SF126, SF767, and M17 cell lines contained the point mutation at the same position （ LRRC4 geneT977A ） （3/5） , which was a synonymous mutation. However, PCR products from gDNA of U251 and U87 cell lines （2/ 5 ） were not obtained. The expression absence of LRRC4 was ascribed to the loss of homozygosity of 7q32-ter in U251 cell lines. Conclusion The expression of LRRC4 gene is absent in glioblastoma cell lines, and it offers the important experiment proof for LRRC4 to act as a new candidate of brain tumor suppressor gene from glioma. The loss of homozygosity of 7q32-ter contributed to the expression absence of LRRC4 in U251 cell lines.