MicroRNAs (miRNAs) are studied as key regulators of gene expression involved in different diseases. Several single nucleotide polymorphisms (SNPs) in miRNA genes or target sites (miRNA-related SNPs) have been proved to be associated with human diseases by affecting the miRNA-mediated regulatory function. To systematically analyze miRNA-related SNPs and their effects, we performed a genome-wide scan for SNPs in human pre-miRNAs, miRNA flanking regions, target sites, and designed a pipeline to predict the effects of them on miRNA–target interaction. As a result, we identified 48 SNPs in human miRNA seed regions and thousands of SNPs in 3′ untranslated regions with the potential to either disturb or create miRNA–target interactions. Furthermore, we experimentally confirmed seven loss-of-function SNPs and one gain-of-function SNP by luciferase assay. This is the first case of experimental validation of an SNP in an miRNA creating a novel miRNA target binding. All useful data were complied into miRNASNP, a user-friendly free online database (http://www.bioguo.org/miRNASNP/). These data will be a useful resource for studying miRNA function, identifying disease-associated miRNAs, and further personalized medicine. Hum Mutat 33:254–263, 2012.

An enormous amount of long non-coding RNAs (lncRNAs) transcribed from eukaryotic genome are important regulators in different aspects of cellular events. Cytoplasm is the residence and the site of action for many lncRNAs. The cytoplasmic lncRNAs play indispensable roles with multiple molecular mechanisms in animal and human cells. In this review, we mainly talk about functions and the underlying mechanisms of lncRNAs in the cytoplasm. We highlight relatively well-studied examples of cytoplasmic lncRNAs for their roles in modulating mRNA stability, regulating mRNA translation, serving as competing endogenous RNAs, functioning as precursors of microRNAs, and mediating protein modifications. We also elaborate the perspectives of cytoplasmic lncRNA studies.