Paper 2: Expression levels of the microRNA maturing microprocessor complex component DGCR8 and the RNA-induced silencing complex (RISC) components argonaute-1, argonaute-2, PACT, TARBP1 and TARBP2 in epithelial skin cancer

Abstract

microRNAs (miRNAs) are thought to play an important role in the posttranscriptional gene regulation of up to 30% of all human genes [1]. The updated version (V.17) of the miRNA database miRBase currently distinguishes 1424 different human miRNA sequences [2]. miRNAs are capable of regulating gene expression both by promoting mRNA degradation and by inhibiting mRNA translation [3]. The maturation of miRNAs occurs in the nucleus and the cytoplasm. The process begins in the nucleus, where the intranuclear enzyme Drosha, an RNase III endonuclease, cleaves pri-miRNAs (consisting of a hairpin stem, a terminal loop, and 5` and 3` single-stranded RNA extensions) to premiRNAs (60-70 nucleotide stem-loop structures).