Bose Krishnashish, Maity Arijit, Ngo Khac Huy, Vandana J Jeya, Shneider Neil A, Phan Anh Tuân
School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore.
Department of Neurology, Columbia University Medical Center, New York, USA.
Biochem Biophys Res Commun. 2022 Jun 25;610:113-118. doi: 10.1016/j.bbrc.2022.03.162. Epub 2022 Apr 4.
In the neurodegenerative disorders amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), expansion of the GC hexanucleotide repeat in the gene C9orf72 is a most common known cause of the disease. Here we use atomic force microscopy (AFM) and gel electrophoresis to visualize the formation of higher-order structures by RNA GC repeats in physiologically relevant conditions. For the RNA sequence r[GCG], we observed G-wires with left-handed undulating features of 4.4-nm periodicity and a uniform height which is consistently higher than that of a duplex B-DNA. These higher-order structures were not degraded fully when treated with a mixture of RNase A and RNase T1. Similarly, higher-order structures were observed for sequences containing three or four GC repeats, pointing towards their potential formation in longer sequence contexts. Our observations suggest that RNA G-quadruplex blocks and G-wires can accumulate in cells containing GC repeat transcripts.
在神经退行性疾病肌萎缩侧索硬化症（ALS）和额颞叶痴呆（FTD）中，基因C9orf72内GC六核苷酸重复序列的扩增是该疾病最常见的已知病因。在此，我们使用原子力显微镜（AFM）和凝胶电泳，以在生理相关条件下可视化RNA GC重复序列形成的高阶结构。对于RNA序列r[GCG]，我们观察到具有4.4纳米周期性的左旋起伏特征且高度均匀的G线，其高度始终高于双链B-DNA。当用核糖核酸酶A和核糖核酸酶T1的混合物处理时，这些高阶结构并未完全降解。同样，对于包含三个或四个GC重复序列的序列也观察到了高阶结构，这表明它们在更长的序列背景中具有形成的潜力。我们的观察结果表明，RNA G-四链体结构域和G线可在含有GC重复转录本的细胞中积累。
