are complicated and difficult to understand. Further studies are required to break the histone modification code, which is implicated in the pathogenesis of autoimmune diseases. It is hoped that advances in our understanding of the roles of histone modifications in autoimmune diseases will provide a better grasp of the pathogenesis of autoimmune diseases and thus help speed the development of new therapeutic strategies and biomarkers for autoimmune diseases. Competing Interests The authors have no conflicting financial interests.Gene expression regulation is highly connected process. Transcriptional regulation is interdependent on posttranscriptional processes both in the nucleus and cytoplasm. Regulatory proteins, such as RNA-binding proteins, play important roles throughout the gene expression program, from the transcription to translation. One such important family of regulatory RBPs is the SerineArginine family of proteins. In this mini-review, the essential Received 30 December, 2016; accepted 6 January, 2017; published online 26 January, 2017 eISSN: 0219-1032 The Korean Society for Molecular and Cellular Biology. Multifunctional SR Proteins Sunjoo Jeong regulate MEK 162 biological activity splicing by 
“splicing code”. SREs include exonic splicing enhancers, exonic splicing suppressors, intronic splicing enhancers, and intronic splicing suppressors. In general, SR proteins bind ESE and enhance the splicing by recruiting the spliceosome. On the contrary, heterogeneous nuclear ribonucleoprotein family proteins can antagonize the positive effect of SR proteins by binding to ESS or ISS and repressing splicing. Essential but complex role of SR proteins in alternative splicing SR proteins are important alternative splicing regulators. In PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19838782 contrast to the robust splicing enhancing effect in constitutive splicing, SR-mediated alternative splicing regulation is more complex and subtle. Alternative exons generally hold shorter length and weaker 5 spliced sites, so SR proteins induce the inclusion of the alternative exon through increasing the recognition of weak splice sites by splicing machinery. Since the regulatory roles of RBPs in alternative splicing are position- and context-dependent, locations of SR-RNA interaction influence splicing outcome. For example, exon-bound SR proteins act as enhancers, but intron-bound SR proteins may function as suppressors. So the location of SR-RNA interactions affect spliceosome assembly and splice site selection. In addition, SR proteins can act as activators or repressors in a contextdependent manner with other RBPs. Fig. 1. List and domains of SR proteins. The domain structures are denoted as shown in the lower box. Current names for SR proteins are SRSFs, but aliases are also indicated in the parenthesis. Among 12 core SR proteins, 6 are reported to shuttle between nucleus and cytoplasm, whereas the others have not been shown to have shuttling activity, as indicated in the upper box. SR PROTEINS AS RNA BINDERS Selection of SR-binding RNA sequences in vitro Since individual SR proteins are not functionally equivalent, SR proteins are believed to bind RNA with unique or preferential specificity. Various analytical techniques for RNAprotein interaction have been utilized to determine the SR-binding RNA sequences. As an approach to identify RNA-binding sequences of SR proteins, in vitro SELEX experiments were performed. SELEX has the advantage of selecting high-affinity consensus RNA sequences to target proteins among large pool o
