Whitelaw E, Proudfoot N
EMBO J. 1986 Nov;5(11):2915-22. doi: 10.1002/j.1460-2075.1986.tb04587.x.
We have investigated the process of transcriptional termination in the duplicated human alpha globin genes which lie 4 kb apart on chromosome 16. In the human erythroleukemic cell line, K562, which expresses high levels of alpha globin, nuclear run-off experiments suggest that termination occurs within a region of 600 bp past the poly(A) site of both alpha 1 and alpha 2 globin genes. However, a thalassaemic alpha 2 globin gene with a non-functional poly(A) site AAUAAG, when transfected into HeLa cells, not only fails to 3' end process but also fails to terminate transcription. Studies on both steady-state RNA and nuclear run-off analysis of the primary transcripts show that transcription of the mutant alpha 2 globin gene reads through into the intergenic sequence past the normal termination site. These results demonstrate that transcriptional termination and 3' end processing of mRNA are coupled events for the alpha 2 globin gene.
我们研究了位于16号染色体上、相距4 kb的重复人类α珠蛋白基因的转录终止过程。在高表达α珠蛋白的人类红白血病细胞系K562中，细胞核连续转录实验表明，终止发生在α1和α2珠蛋白基因的聚腺苷酸化位点下游600 bp的区域内。然而，一个具有无功能聚腺苷酸化位点AAUAAG的地中海贫血α2珠蛋白基因，转染到HeLa细胞后，不仅不能进行3'末端加工，也不能终止转录。对稳态RNA和初级转录本的细胞核连续转录分析表明，突变的α2珠蛋白基因的转录会通读正常终止位点，进入基因间序列。这些结果表明，α2珠蛋白基因的转录终止和mRNA的3'末端加工是偶联事件。
