Wang M, Dotzlaw H, Fuqua S A, Murphy L C
Department of Biochemistry, University of Manitoba, Winnipeg, Canada. nucleotide insertion.
Breast Cancer Res Treat. 1997 Jun;44(2):145-51. doi: 10.1023/a:1005753117205.
A novel ER-like mRNA containing a 69 nucleotide insertion precisely between exon 5 and 6 sequences was previously identified in human breast cancer biopsy samples. Data are presented which suggest that the 69 nucleotide sequence is normally present in intron 5 of the human estrogen receptor gene. The region corresponding to and surrounding this 69 nucleotide sequence was cloned and the nucleotide sequence determined. Cloning and sequencing of the corresponding region in genomic DNA isolated from a breast tumor expressing the 69 nucleotide inserted ER mRNA, revealed an A-->G point mutation immediately 3' to the 69 nucleotide sequence. This point mutation resulted in the generation of a consensus splice donor site. A consensus splice acceptor site sequence is normally present immediately 5' to the 69 nucleotide sequence. These data are consistent with the 69 nucleotide sequence being recognized as an exon by the splicing machinery, and resulting in processing of a mature ER mRNA containing the 69 nucleotide insert.
先前在人类乳腺癌活检样本中鉴定出一种新型的类雌激素受体（ER）mRNA，其在第5外显子和第6外显子序列之间精确插入了一段69个核苷酸的序列。所呈现的数据表明，该69个核苷酸的序列正常情况下存在于人类雌激素受体基因的第5内含子中。对与该69个核苷酸序列相对应及周边的区域进行了克隆，并测定了核苷酸序列。对从表达插入了69个核苷酸的ER mRNA的乳腺肿瘤中分离出的基因组DNA的相应区域进行克隆和测序，结果显示在69个核苷酸序列的3'端紧邻处有一个A→G点突变。该点突变导致产生了一个共有剪接供体位点。在69个核苷酸序列的5'端紧邻处通常存在一个共有剪接受体位点序列。这些数据与剪接机制将69个核苷酸序列识别为一个外显子，并导致加工出含有69个核苷酸插入片段的成熟ER mRNA相一致。
