The pervasive transcription of the genome creates many types of non-coding RNAs(nc RNAs).However,we know very little regarding the functions and the regulatory mechanisms of these nc RNAs.Exploring the interactions of RNA and RNA binding proteins(RBPs) is vital because it can allow us to truly understand how these nc RNAs behave in vivo.High-throughput sequencing of RNA isolated by cross-linking immunoprecipitation(HITS-CLIP or CLIP-seq) and its variants have been successfully used as systemic techniques to study RBP binding sites.In this review,we will explain the major differences between the CLIP techniques,summarize successful applications of these techniques,discuss limitations of CLIP,present some suggested solutions and project their promising future roles in studying the RNA world.
microRNAs （miRNAs） constitute a unique class of endogenous small non-coding RNAs that regulate gene expression post-transcriptionally. Studies over the past decade have uncovered a r^curring paradigm in which miRNAs are key regulators of cellular behavior under various physiological and pathological conditions. Most surprising is the recent observation that miRNAs have emerged as competent players in somatic cell reprogramming, suggesting an especially significant role for these small RNAs in cell fate settings. Here, we discuss the possible mechanisms underlying miRNA-mediated cell programming （i.e., the development and differentiation of embryonic stem cells） and reprogramming （i.e., turning somatic cells into pluripo- tent stem cells or other lineages）, and provide a ＂Helm＂ model of miRNAs in cell fate decision and conversion.
