Dynamic microRNAome profiles in the developing porcine liver

<p>Increasing evidence suggests that micro (mi)RNAs play important roles in various biological process. To evaluate the roles of miRNA in the porcine liver, we investigated the dynamic profiles of microRNAomes using liver tissue from pigs during the embryonic period (embryonic day 90), weaning stage (postnatal day 30), and adult stage (7 years old). A total of 186 unique miRNAs were differentially expressed during liver development. We also identified that 17, 13, and 6 miRNAs were specifically abundant at embryonic day 90, postnatal day 30, and at 7 years, respectively. Besides regulating basic cellular roles in development, miRNAs expressed at the three developmental stages also participated in regulating “embryonic liver development,” “early hepatic growth and generating a functioning liver,” and “energy metabolic processes,” respectively. Our study indicates that miRNAs are extensively involved in liver development, and provides a valuable resource for the further elucidation of miRNA regulatory roles during liver development.</p> <p>miRNAs are extensively involved in liver development, especially for these stage-enriched miRNAs.</p

Spontaneous single nucleotide polymorphism in porcine microRNA-378 seed region leads to functional alteration

<p>Sequence variation in a microRNA (miRNA) seed region can influence its biogenesis and effects on target mRNAs; however, in mammals, few seed region mutations leading to functional alterations have been reported to date. Here, we report the identification of a single nucleotide polymorphism (SNP) with functional consequence located in the seed region of porcine miR-378. <i>In vitro</i> analysis of this rs331295049 A17G SNP showed significantly up-regulated expression of the mature miR-378 (miR-378/G). <i>In silico</i> target prediction indicated that the SNP would modulate secondary structure and result in functional loss affecting >85% of the known target genes of the wild-type miR-378 (miR-378/A), and functional gain affecting >700 new target genes, and dual-luciferase reporter assay verified this result. This report of a SNP in the seed region of miR-378 leads to functional alteration and indicates the potential for substantive functional consequences to the molecular physiology of a mammalian organism.</p> <p>The SNP changed the secondary structure of pre-miR-378 and increased the production of mutant miR-378. Functionally, the SNP lead to loss and gain of miR-378 targets.</p