Genomics：非编码序列L1与癌症发生相关

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英国研究人员日前报告说，人类基因组中一些“垃圾DNA”产生的物质与乳腺癌等癌症存在相关性，这项发现有助于研发新的癌症治疗方法。8 b' a1 w# M3 b

4 p% s( D9 m3 o3 u& S" h) K* b) Z英国诺丁汉大学等机构研究人员在美国《基因组学》杂志上报告说，他们发现人类基因组中名为L1的DNA序列会导致生成一些反常产物，而这些产物多见于乳腺癌细胞中。
0 G) u2 p5 e4 J- WGenomics December 2009 doi:10.1016/j.ygeno.2009.08.013  
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Isolation of cancer-specific chimeric transcripts induced by hypomethylation of the LINE-1 antisense promoter
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Hazel A. Cruickshanksa, b and Cristina Tufarelli, a, b, ' s. l  T: C7 Z' F- ~, s! v  c

! z/ X0 @' }  t) ~8 y$ V( caWolfson Centre for Stem Cells, Tissue Engineering and Modelling (STEM), Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
+ g2 t1 [  s9 q6 K, ObDepartment of Genetics, University of Leicester, Leicester, LE1 7RH, UK
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7 W1 T5 P4 ^$ Z' l/ p9 M: n, x- bThe antisense promoter of human LINE-1 (L1) retroelements can direct transcription of adjacent unique genomic sequences generating chimeric RNAs, which can perturb transcription of neighbouring genes. As L1 elements constitute 17% of the human genome, chimeric transcription is potentially widespread, but the extent to which this occurs is largely unknown. Using a genome-wide screen we have isolated novel chimeric transcripts that are unique to breast cancer cell lines, primary tumours and colon cancer cells. Expression of the cancer-specific chimeric transcripts can be induced in non-malignant breast epithelial cells by the demethylating drug 5-azacytidine. These findings indicate that loss of L1 methylation in cancer cells is linked to the expression of L1-chimeric transcripts which may therefore constitute a useful set of markers of malignancy.