Global analysis of microRNA target gene expression reveals that miRNA targets are lower expressed in mature mouse and Drosophila tissues than in the embryos

Abstract

MicroRNAs (miRNAs) are non-coding small RNAs of ∼22 nt that regulate the gene expression by base pairing with target mRNAs, leading to mRNA cleavage or translational repression. It is currently estimated that miRNAs account for ∼1% of predicted genes in higher eukaryotic genomes and that up to 30% of genes might be regulated by miRNAs. However, only very few miRNAs have been functionally characterized and the general functions of miRNAs are not globally studied. In this study, we systematically analyzed the expression patterns of miRNA targets using several public microarray profiles. We found that the expression levels of miRNA targets are lower in all mouse and Drosophila tissues than in the embryos. We also found miRNAs more preferentially target ubiquitously expressed genes than tissue-specifically expressed genes. These results support the current suggestion that miRNAs are likely to be largely involved in embryo development and maintaining of tissue identity.

The Oncogenic Role of miR-155 in Breast Cancer

“…The short length of the seed sequence facilitates the targeting of many transcripts by a single miRNA (3). Some estimates suggest that 30% of all eukaryotic genes are regulated by miRNAs (4,5). miR-155, a miRNA widely reported to be involved in lymphoma, is also now emerging to have a role in the progression of solid cancers (6).…”

An Array-Based Analysis of MicroRNA Expression Comparing Matched Frozen and Formalin-Fixed Paraffin-Embedded Human Tissue Samples

“…Currently, it is estimated that up to 30% of protein coding genes might be regulated by miRNAs at the posttranscriptional level. 4,5 Recent studies have demonstrated that miRNAs regulate various cell functions, including cell proliferation, differentiation, death, stress resistance, and fat metabolism. 4 -6 Accordingly, it is reasonable to suggest that abnormal miRNAs expression is likely to contribute to human disease, including cancer.…”

MiRNAs-based Gene Therapy on the Horizon: Novel and Effective Therapeutic Advancement

“…They found that the expression levels of miRNA targets are significantly lower in all mouse mature tissues and Drosophila later life stages than in the embryos. These results point out that miRNAs may play roles in determining the timing of tissue differentiation during the larva period of Drosophila development and maintaining the tissue identity during adulthood [66].…”