LncRNA-GAS5抑制miR-21介导的非完全匹配靶mRNA降解

LncRNA-GAS5 Inhibits Decay of microRNA-21 Imperfect Complementary Target mRNAs

LncRNA-GAS5作为miR-21的"分子海绵",通过"吸收"miR-21从而调控miR-21对靶基因的抑制.此外,miR-21直接调控非完全匹配靶基因PTEN和TPM1的表达.我们首先在HEK293T和HeLa细胞中确认,miR-21通过碱基互补配对调控非完全匹配靶基因PTEN和TPM1的蛋白表达,但不影响PTEN和TPM1mRNA的水平.此外,过表达miR-21后,qRT-PCR检测PTEN和TPM1mRNA的半衰期,发现它们的半衰期显著缩短,miR-21加速PTEN和TPM1mRNA的降解.通过转染lncRNA-GAS5的过表达质粒,发现lncRNA-GAS5竞争性地与miR-21结合能够延长PTEN和TPM1mRNA的半衰期,而miR-21与lncRNA-GAS5碱基互补配对结合后,又对lncRNA-GAS5存在调节作用,减弱lncRNA-GAS5的稳定性并加速lncRNA-GAS5的降解.LncRNA-GAS5作为miR-21的"分子海绵"能够抑制miR-21对非完全匹配靶mRNAPTEN和TPM1的降解,同时,miR-21与lncRNA-GAS5结合后又存在对lncRNA-GAS5的反馈调节,这些相互作用机制的发现有助于了解lncRNA、miRNA、mRNA之间这个复杂又精细的调控环路.

LncRNA-GAS5 can act as a ＂ sponge＂ for microRNA-21（miR-21） by competitively sequestering miR-21 from binding target m RNAs. Moreover, miR-21 directly regulates PTEN and TPM1 via imperfect complementary target base pairing.We confirmed miR-21 regulates PTEN and TPM1 protein expression without significantly affecting PTEN and TPM1 m RNA expression via imperfect complementary target binding in HEK293 T and He La cells. Furthermore, Overexpressing miR-21 could significantly shorten half-lives of PTEN and TPM1, miR-21 enhanced PTEN and TPM1 decay.Cells were transfected with lncRNA-GAS5 expression vector, we found lncRNA-GAS5 competitively bound miR-21 and increased the half-lives of PTEN and TPM1.Besides, miR-21 bound with lncRNA-GAS5 could lead rapid decay of lncRNA-GAS5. This study indicates lncRNA-GAS5 functions as a miR-21 ＂ sponge＂ that inhibits m RNA degradation of the miR-21 imperfect complementary targets PTEN and TPM1, and miR-21 also could regulate lncRNA-GAS5 stability by base pairing.Further exploration of the mechanisms may improve our understanding of the lncRNA-miRNA-m RNA sophisticated regulatory feedback loop.