TFE3 内含子 2 处的 G-四链体结构及其在 Xp11.2 易位和剪接中的作用。

G-quadruplex structure at intron 2 of TFE3 and its role in Xp11.2 translocation and splicing.

机构信息

Centre for Genetic Disorders, Institute of Science, Banaras Hindu University, Varanasi 221005, INDIA.

出版信息

Biochim Biophys Acta Gen Subj. 2018 Mar;1862(3):630-636. doi: 10.1016/j.bbagen.2017.11.011. Epub 2017 Nov 11.

DOI:10.1016/j.bbagen.2017.11.011

Abstract

Transcription Factor E3 (TFE3) translocation is found in a group of different type of cancers and most of the translocations are located in the 5' region of TFE3 which may be considered as Breakpoint Region (BR). In our In silico study by QGRS mapper and non BdB web servers we found a Potential G-quadruplex forming Sequence (PQS) in the intron 2 of TFE3 gene. In vitro G-quadruplex formation was shown by native PAGE in presence of Pyridostatin(PDS), which with inter molecular secondary structure caused reduced mobility to migrate slower. G-quadruplex formation was mapped at single base resolution by Sanger sequencing and Circular Dichroism showed the formation of parallel G-quadruplex. FRET analysis revealed increased and decreased formation of G-quadruplex in presence of PDS and antisense oligonucleotide respectively. PCR stop assay, transcriptional and translational inhibition by PQS showed stable G-quadruplex formation affecting the biological processes. TFE3 minigene splicing study showed the involvement of this G-quadruplex in TFE3 splicing too. Therefore, G-quadruplex is evident to be the reason behind TFE3 induced oncogenesis executed by translocation and also involved in the mRNA splicing.

摘要

转录因子 E3（TFE3）易位存在于一组不同类型的癌症中，大多数易位位于 TFE3 的 5' 区域，可视为断裂点区域（BR）。在我们通过 QGRS mapper 和非 BdB web 服务器进行的计算机研究中，我们在 TFE3 基因的内含子 2 中发现了一个潜在的 G-四链体形成序列（PQS）。在存在吡啶并[3,4-d]嘧啶（PDS）的情况下，通过天然 PAGE 显示了体外 G-四链体的形成，这与分子间二级结构一起导致迁移速度降低，迁移速度变慢。通过 Sanger 测序以单碱基分辨率对 G-四链体形成进行了映射，圆二色性显示形成了平行 G-四链体。荧光共振能量转移（FRET）分析显示，在存在 PDS 和反义寡核苷酸的情况下，G-四链体的形成分别增加和减少。PCR 停止测定、PQS 对转录和翻译的抑制显示了稳定的 G-四链体形成，影响了生物过程。TFE3 迷你基因剪接研究表明，这种 G-四链体也参与了 TFE3 的剪接。因此，G-四链体显然是 TFE3 易位诱导致癌的原因，也参与了 mRNA 剪接。