Faculty of Science, Department of Chemistry, Shizuoka University , 836 Ohya Suruga, Shizuoka, 422-8529, Japan.
J Am Chem Soc. 2013 Dec 4;135(48):18016-9. doi: 10.1021/ja4086929. Epub 2013 Nov 20.
Telomeric repeat-containing RNA (TERRA), which contains tandem arrays of short RNA repeats, r(UUAGGG), is an integral component of the telomere and contributes to telomeric heterochromatin formation and telomere-length regulation. TERRA forms a G-quadruplex, but the biologic significance of its G-quadruplex formation is unknown. Compounds that selectively bind to G-quadruplex RNA are useful for understanding G-quadruplex TERRA. Here we report that an engineered RGG domain translocated in liposarcoma (TLS) specifically binds to G-quadruplex TERRA. The Arg-Gly-Gly repeat (RGG) TLS binds to G-quadruplex human telomere DNA and TERRA simultaneously, but we show that substitution of Tyr for Phe in the RGG domain of TLS (TLSRGG3Y) converts its binding specificity solely toward G-quadruplex TERRA. TLSRGG3Y binds to dG tetrads with abasic RNA loops, but fails to bind to rG tetrads without loops or dG tetrads with abasic DNA loops. These findings suggest that TLSRGG3Y binds to loops within the G-quadruplexes of TERRA by recognizing the 2'-OH of the riboses. To our knowledge, TLSRGG3Y is the first known molecule that specifically recognizes the 2'-OH of the riboses of loops in the G-quadruplex. TLSRGG3Y will be useful for investigating the role of the G-quadruplex form of TERRA without affecting G-quadruplex telomere DNA functions.
端粒重复 RNA（TERRA）含有短 RNA 重复序列 UUAGGG 的串联阵列，是端粒的组成部分，有助于形成端粒异染色质和调节端粒长度。TERRA 形成 G-四链体，但 G-四链体形成的生物学意义尚不清楚。选择性结合 G-四链体 RNA 的化合物可用于研究 G-四链体 TERRA。在这里，我们报告一种工程化的富含精氨酸-甘氨酸-甘氨酸的结构域易位性脂肪肉瘤（TLS）蛋白特异性结合 G-四链体 TERRA。Arg-Gly-Gly 重复（RGG）TLS 同时结合 G-四链体人端粒 DNA 和 TERRA，但我们表明，TLS 的 RGG 结构域中 Phe 被 Tyr 取代（TLSRGG3Y）会使其结合特异性完全转向 G-四链体 TERRA。TLSRGG3Y 与具有无碱基 RNA 环的 dG 四联体结合，但不能与无环的 rG 四联体或具有无碱基 DNA 环的 dG 四联体结合。这些发现表明，TLSRGG3Y 通过识别核糖的 2'-OH 结合到 TERRA 的 G-四联体环中。据我们所知，TLSRGG3Y 是第一个已知的专门识别 G-四联体环中核糖 2'-OH 的分子。TLSRGG3Y 将有助于研究 G-四链体形式的 TERRA 的作用，而不会影响 G-四链体端粒 DNA 的功能。
