Kang S, Jaworski A, Ohshima K, Wells R D
Institute of Biosciences and Technology, Texas A&M University, Texas Medical Center, Houston 77030, USA.
Nat Genet. 1995 Jun;10(2):213-8. doi: 10.1038/ng0695-213.
Several human hereditary neurological and neurodegenerative disease genes are associated with the expansion of CTG repeats. Here we show that the frequency of genetic expansions or deletions in Escherichia coli depends on the direction of replication. Large expansions occur predominantly when the CTGs are in the leading strand template rather than the lagging strand. However, deletions are more prominent when the CTGs are in the opposite orientation. Most deletions generated products of defined size classes. Strand slippage coupled with non-classical DNA structures may account for these observations and relate to expansion-deletion mechanisms in eukaryotic chromosomes for disease genes.
几种人类遗传性神经和神经退行性疾病基因与CTG重复序列的扩增有关。我们在此表明，大肠杆菌中基因扩增或缺失的频率取决于复制方向。当CTG位于前导链模板而非滞后链时，主要发生大的扩增。然而，当CTG处于相反方向时，缺失更为明显。大多数缺失产生了特定大小类别的产物。链滑动与非经典DNA结构相结合可能解释了这些观察结果，并与疾病基因在真核染色体中的扩增-缺失机制有关。
