Evolutionary and Expression Analysis of miR-#-5p and miR-#-3p at the miRNAs/isomiRs Levels

Li Guo,Hao Yu,Feng Chen,Jiafeng Yu,Shujie Chen,Changqing Xu,Yang Zhao

doi:10.1155/2015/168358

Li Guo, Hao Yu + Show 5 more

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https://doi.org/10.1155/2015/168358

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Abstract

We mainly discussed miR-#-5p and miR-#-3p under three aspects: (1) primary evolutionary analysis of human miRNAs; (2) evolutionary analysis of miRNAs from different arms across the typical 10 vertebrates; (3) expression pattern analysis of miRNAs at the miRNA/isomiR levels using public small RNA sequencing datasets. We found that no bias can be detected between the numbers of 5p-miRNA and 3p-miRNA, while miRNAs from miR-#-5p and miR-#-3p show variable nucleotide compositions. IsomiR expression profiles from the two arms are always stable, but isomiR expressions in diseased samples are prone to show larger degree of dispersion. miR-#-5p and miR-#-3p have relative independent evolution/expression patterns and datasets of target mRNAs, which might also contribute to the phenomena of arm selection and/or arm switching. Simultaneously, miRNA/isomiR expression profiles may be regulated via arm selection and/or arm switching, and the dynamic miRNAome and isomiRome will adapt to functional and/or evolutionary pressures. A comprehensive analysis and further experimental study at the miRNA/isomiR levels are quite necessary for miRNA study.

Highlights

IntroductionMicroRNAs (miRNAs) have been widely studied as a class of well-conserved negative regulatory molecules
MicroRNAs have been widely studied as a class of well-conserved negative regulatory molecules
Based on the current annotated human miRNAs, similar numbers of 5p-miR and 3p-miR show well-conserved sequences across different species, they are involved in inconsistent length distributions and nucleotide compositions, including multiple repetitive nucleotides (Figures 1(a)–1(c), Figure 2, and Table 1)

Summary

Introduction

MicroRNAs (miRNAs) have been widely studied as a class of well-conserved negative regulatory molecules. They play an important role in biological processes by regulating gene expression at the posttranscriptional level [1, 2]. Increasing evidence indicates that both arms can generate mature miRNAs under specific developmental stages or species [7,8,9,10,11,12,13]. Increasing reports indicate that the nondominantly expressed miRNA sequences may act as potential regulatory molecules with unexpectedly abundant expression levels [16,17,18]

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