Wheway Joanna M, Roberts Roland G
Division of Medical and Molecular Genetics, GKT Medical School, 8th Floor, Guy's Tower, Guy's Hospital, London SE1 9RT, UK.
Neuromuscul Disord. 2003 Jan;13(1):17-20. doi: 10.1016/s0960-8966(02)00195-5.
The human dystrophin gene has seven generally recognised promoters and one, the so-called lymphocyte promoter, whose status remains uncertain. We re-evaluated this promoter in the light of recently available human and mouse genome sequences, and attempted to compare its activity in lymphocytes with that of the muscle promoter. We find that the lymphocyte promoter lies immediately adjacent to the chronic granulomatous disease gene, CYBB, approximately 4.5 megabases upstream of dystrophin exon 2. This makes the supposed lymphocyte dystrophin primary transcript 7 megabases in size, with an expected transcription time in excess of 2 days. We also find that lymphocyte promoter use in peripheral blood lymphocytes is negligible compared to that of the muscle promoter in the same tissue. Together with the presence in the intron of a sense-strand multi-exon gene, and lack of conserved linkage in the mouse, we propose that the lymphocyte promoter is not a biologically significant part of the dystrophin gene.
人类肌营养不良蛋白基因有七个普遍公认的启动子，还有一个所谓的淋巴细胞启动子，其地位仍不确定。我们根据最近可得的人类和小鼠基因组序列重新评估了这个启动子，并试图比较其在淋巴细胞中的活性与肌肉启动子的活性。我们发现淋巴细胞启动子紧邻慢性肉芽肿病基因CYBB，位于肌营养不良蛋白外显子2上游约450万个碱基对处。这使得假定的淋巴细胞肌营养不良蛋白初级转录本大小为700万个碱基对，预计转录时间超过2天。我们还发现，与同一组织中的肌肉启动子相比，外周血淋巴细胞中淋巴细胞启动子的使用可以忽略不计。再加上有义链多外显子基因内含子的存在，以及小鼠中缺乏保守的连锁关系，我们认为淋巴细胞启动子不是肌营养不良蛋白基因具有生物学意义的一部分。
