Two evolutionary developmental strategies for miRNA gene regulation in animal embryogenesis [DM_miRNA-seq]
Ontology highlight
ABSTRACT: miRNAs play essential roles in the mechanics of gene regulation, however, on an organismal-scale, the processes in they are deployed are not well understood. Here, we adopt an evolutionary developmental approach to study miRNA function by examining their expression throughout embryogenesis in both C. elegans and D. melanogaster. We find that, in both species, the miRNA complement of the transcriptome shifts in a punctuated fashion during the previously identified mid-developmental transition specifying two dominant modes of miRNA expression: an early and a late profile. Strikingly, we find that phylogenetically conserved miRNAs are expressed late, while early expressed miRNAs are inversely expressed with their targets suggesting strong target-inhibition. Our work exposes two distinct strategies of miRNA function comprising late-expressed physiological roles and early expressed repressive roles. In summary, the expression of miRNAs throughout embryogenesis in two species implicates their role in the canalization of cell-types during late phases of embryogenesis and repressing targets to lock-down misexpression.
Project description:miRNAs play essential roles in the mechanics of gene regulation, however, on an organismal-scale, the processes in they are deployed are not well understood. Here, we adopt an evolutionary developmental approach to study miRNA function by examining their expression throughout embryogenesis in both C. elegans and D. melanogaster. We find that, in both species, the miRNA complement of the transcriptome shifts in a punctuated fashion during the previously identified mid-developmental transition specifying two dominant modes of miRNA expression: an early and a late profile. Strikingly, we find that phylogenetically conserved miRNAs are expressed late, while early expressed miRNAs are inversely expressed with their targets suggesting strong target-inhibition. Our work exposes two distinct strategies of miRNA function comprising late-expressed physiological roles and early expressed repressive roles. In summary, the expression of miRNAs throughout embryogenesis in two species implicates their role in the canalization of cell-types during late phases of embryogenesis and repressing targets to lock-down misexpression.
Project description:miRNAs play essential roles in the mechanics of gene regulation, however, on an organismal-scale, the processes in they are deployed are not well understood. Here, we adopt an evolutionary developmental approach to study miRNA function by examining their expression throughout embryogenesis in both C. elegans and D. melanogaster. We find that, in both species, the miRNA complement of the transcriptome shifts in a punctuated fashion during the previously identified mid-developmental transition specifying two dominant modes of miRNA expression: an early and a late profile. Strikingly, we find that phylogenetically conserved miRNAs are expressed late, while early expressed miRNAs are inversely expressed with their targets suggesting strong target-inhibition. Our work exposes two distinct strategies of miRNA function comprising late-expressed physiological roles and early expressed repressive roles. In summary, the expression of miRNAs throughout embryogenesis in two species implicates their role in the canalization of cell-types during late phases of embryogenesis and repressing targets to lock-down misexpression.
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that can exert multilevel inhibition/repression at a post-transcriptional or protein synthesis level during disease or development. Characterisation of miRNAs in adult mammalian brains by deep sequencing has been reported previously. However, to date, no small RNA profiling of the developing brain has been undertaken using this method. We have performed deep sequencing and small RNA analysis of a developing (E15.5) mouse brain. We identified the expression of 294 known miRNAs in the E15.5 developing mouse brain, which were mostly represented by let-7 family and other brain-specific miRNAs such as miR-9 and miR-124. We also discovered 4 putative 22-23nt miRNAs: mm_br_e15_1181, mm_br_e15_279920, mm_br_e15_96719 and mm_br_e15_294354 each with a 70-76nt predicted pre-miRNA. We validated the 4 putative miRNAs and further characterised one of them, mm_br_e15_1181, throughout embryogenesis. Mm_br_e15_1181 biogenesis was Dicer1-dependent and was expressed in E3.5 blastocysts and E7 whole embryos. Embryo-wide expression patterns were observed at E9.5 and E11.5 followed by a near complete loss of expression by E13.5, with expression restricted to a specialised layer of cells within the developing and early postnatal brain. Mm_br_e15_1181 was upregulated during neurodifferentiation of P19 teratocarcinoma cells. This novel miRNA has been identified as miR-3099. We have generated and analysed the first deep sequencing dataset of small RNA sequences of the developing mouse brain. The analysis revealed a novel miRNA, miR-3099, with potential regulatory effects on early embryogenesis, and involvement in neuronal cell differentiation/function in the brain during late embryonic and early neonatal development. Deep sequencing analysis of small RNAs isolated from an E15.5 mouse brain.
Project description:As the fetal heart develops, cardiomyocyte proliferation potential decreases while fatty acid oxidative capacity increases, a highly regulated transition known as cardiac maturation. Small noncoding RNAs, such as microRNAs (miRNAs), contribute to the establishment and control of tissue-specific transcriptional programs. However, small RNA expression dynamics and genome wide miRNA regulatory networks controlling maturation of the human fetal heart remain poorly understood. Transcriptome profiling of small RNAs revealed the temporal expression patterns of miRNA, piRNA, circRNA, snoRNA, snRNA and tRNA in the developing human heart between 8 and 19 weeks of gestation. Our analysis revealed that miRNAs were the most dynamically expressed small RNA species throughout mid-gestation. Cross-referencing differentially expressed miRNAs and mRNAs predicted 6,200 mRNA targets, 2134 of which were upregulated and 4066 downregulated as gestation progresses. Moreover, we found that downregulated targets of upregulated miRNAs predominantly control cell cycle progression, while upregulated targets of downregulated miRNAs are linked to energy sensing and oxidative metabolism. Furthermore, integration of miRNA and mRNA profiles with proteomes and reporter metabolites revealed that proteins encoded in mRNA targets, and their associated metabolites, mediate fatty acid oxidation and are enriched as the heart develops.This study revealed the small RNAome of the maturing human fetal heart. Furthermore, our findings suggest that coordinated activation and repression of miRNA expression throughout mid-gestation is essential to establish a dynamic miRNA-mRNA-protein network that decreases cardiomyocyte proliferation potential while increasing the oxidative capacity of the maturing human fetal heart.
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that can exert multilevel inhibition/repression at a post-transcriptional or protein synthesis level during disease or development. Characterisation of miRNAs in adult mammalian brains by deep sequencing has been reported previously. However, to date, no small RNA profiling of the developing brain has been undertaken using this method. We have performed deep sequencing and small RNA analysis of a developing (E15.5) mouse brain. We identified the expression of 294 known miRNAs in the E15.5 developing mouse brain, which were mostly represented by let-7 family and other brain-specific miRNAs such as miR-9 and miR-124. We also discovered 4 putative 22-23nt miRNAs: mm_br_e15_1181, mm_br_e15_279920, mm_br_e15_96719 and mm_br_e15_294354 each with a 70-76nt predicted pre-miRNA. We validated the 4 putative miRNAs and further characterised one of them, mm_br_e15_1181, throughout embryogenesis. Mm_br_e15_1181 biogenesis was Dicer1-dependent and was expressed in E3.5 blastocysts and E7 whole embryos. Embryo-wide expression patterns were observed at E9.5 and E11.5 followed by a near complete loss of expression by E13.5, with expression restricted to a specialised layer of cells within the developing and early postnatal brain. Mm_br_e15_1181 was upregulated during neurodifferentiation of P19 teratocarcinoma cells. This novel miRNA has been identified as miR-3099. We have generated and analysed the first deep sequencing dataset of small RNA sequences of the developing mouse brain. The analysis revealed a novel miRNA, miR-3099, with potential regulatory effects on early embryogenesis, and involvement in neuronal cell differentiation/function in the brain during late embryonic and early neonatal development.
Project description:MicroRNA (miRNA) dysregulation is well-documented in psychiatric disease, but miRNA dynamics during adolescent and early adult brain maturation, when symptoms first appear for many of these diseases, remain poorly understood. Here, we use RNA sequencing to examine miRNAs and their mRNA targets in cortex and hippocampus from early, mid-, and late adolescent and adult mice. We also use Quantitative Proteomics by tandem mass tag mass spectrometry (TMT-MS) to examine protein dynamics in cortex from the same subjects.
Project description:miRNAs are short regulatory single stranded RNA sequences that upon complementary binding to mRNAs lead to the inhibition or degradation of their targets. This regulatory mechanisms has been shown to play crucial roles throughout the whole life cycle of animals and plants as well as in disease. While a plethora of methods exist to predict targets of miRNA, which suggest that up to 80% of the genome is miRNA regulated, it has recently been reported that many of these predictions are false positives, cell type specific or represent non-functional binding. In order to identify the subset of real functional miRNAs and their targets, we established miRNA pathway mutants in mouse embryonic stem cells (mESC), allowing the dissection of canonical and non-canonical functions of pathway members. Additional data integration of downstream regulatory layers (CLIP-seq, ribosome profiling and MS) enabled us to follow and track down real functional miRNA-gene interactions, which reduced the miRNA genome regulation to approximately 1%.
Project description:Background: MicroRNAs (miRNAs) are expressed by a wide range of eukaryotic organisms, and function in diverse biological processes. Numerous miRNAs have been identified in Bombyx mori, but the temporal expression profiles of miRNAs corresponding to each stage transition over the entire life cycle of the silkworm remain to be established. To obtain a comprehensive overview of the correlation between miRNA expression and stage transitions, we performed a whole-life test and subsequent stage-by-stage examinations on nearly one hundred miRNAs in the silkworm. Results: Our results show that miRNAs display a wide variety of expression profiles over the whole life of the silkworm, including continuous expression from embryo to adult (bmo-miR-184), up-regulation over the entire life cycle (bmo-let-7 and miR-100), down-regulation over the entire life cycle (miR-124), expression associated with embryogenesis (miR-29 and miR-92), up-regulation from early 3rd instar to pupa (miR-275), and complementary pulses in expression between miR-34b and miR-275. Stage-by-stage examinations revealed further expression patterns, such as emergence at specific time-points during embryogenesis and up-regulation of miRNA groups in late embryos (miR-1 and bantam), expression associated with stage transition between instar and molt larval stages (miR-34b), expression associated with silk gland growth and spinning activity (miR-274), continuous high expression from the spinning larval to pupal and adult stages (miR-252 and miR-31a), a coordinate expression trough in day 3 pupae of both sexes (miR-10b and miR-281), up-regulation in pupal metamorphosis of both sexes (miR-29b), and down-regulation in pupal metamorphosis of both sexes (miR-275). Conclusions: We present the full-scale expression profiles of miRNAs throughout the life cycle of Bombyx mori. The whole-life expression profile was further investigated via stage-by-stage analysis. Our data provide an important resource for more detailed functional analysis of miRNAs in this animal. In the study presented here, we performed a whole-life test and subsequent stage-by-stage examinations on nearly one hundred miRNAs in the silkworm, leading to a comprehensive overview of the correlation between miRNA expression and stage transitions. In all, 59 unique developmental timepoints were inspected in this study.
Project description:During early vertebrate development, a large number of noncoding RNAs are maternally inherited or expressed upon activation of zygotic transcription. The exact identity, expression levels, and function during early vertebrate development for most of these noncoding RNAs remains largely unknown. miRNAs (microRNAs) and piRNAs (piwi-interacting RNAs) are two classes of small non-coding RNAs that play important roles in gene regulation during early embryonic development. Here, we utilized Illumina next generation sequencing technology to determine temporal expression patterns for both miRNAs and piRNAs during four distinct stages of early vertebrate development using zebrafish as a model system. For miRNAs, the expression patterns for 192 known miRNAs and 12 novel miRNAs within 123 different miRNA families were determined. Significant sequence variation was observed at the 5' and 3' ends of miRNAs with a large number of extra nucleotides added in a non-template directed manner. We also identified a large and diverse set of piRNAs expressed during early development, far beyond that expected if piRNA expression is restricted to germ cells. Our analyses represent the deepest investigation to date of small RNA expression during early vertebrate development and suggest important novel functions for small RNAs during embryogenesis. Identify the expression of small RNAs in zebrafish embryos of four different developmental stages using high through-put sequencing
Project description:During early vertebrate development, a large number of noncoding RNAs are maternally inherited or expressed upon activation of zygotic transcription. The exact identity, expression levels, and function during early vertebrate development for most of these noncoding RNAs remains largely unknown. miRNAs (microRNAs) and piRNAs (piwi-interacting RNAs) are two classes of small non-coding RNAs that play important roles in gene regulation during early embryonic development. Here, we utilized Illumina next generation sequencing technology to determine temporal expression patterns for both miRNAs and piRNAs during four distinct stages of early vertebrate development using zebrafish as a model system. For miRNAs, the expression patterns for 192 known miRNAs and 12 novel miRNAs within 123 different miRNA families were determined. Significant sequence variation was observed at the 5' and 3' ends of miRNAs with a large number of extra nucleotides added in a non-template directed manner. We also identified a large and diverse set of piRNAs expressed during early development, far beyond that expected if piRNA expression is restricted to germ cells. Our analyses represent the deepest investigation to date of small RNA expression during early vertebrate development and suggest important novel functions for small RNAs during embryogenesis.