Project description:Purpose: High-throughput RNA sequencing has accelerated discovery of the complex regulatory roles of small RNAs, such those derived from tRNAs. Also recent advances in high-throughput RNA sequencing has revealed the complex RNA modification landscape and the complex role these nucleosides modifactions have in cell signalling, stem cell biology and development. The goal of this study is to establish how tRNA-derived small RNAs can affect stem cell function. Methods: four replicates of tRNAs sequencing of wild-type (WT) and NSun2 -/- mouse embryonic frontal lobes at E18.5 were generated by deep sequencing, using Illumina HiSeq platform. Results: Our analyses reveal that deletion of the cytosine-5 tRNA methylase NSUN2 increases tRNA cleaveage of NSUN2 tRNA substrates.
Project description:Argonaute/Piwi proteins associate with small RNAs that typically provide sequence specificity for RNP function in gene and genome regulation. Here we show that Twi12, a Tetrahymena Piwi protein essential for growth, is loaded with mature tRNA fragments. The tightly bound ~18-22 nt tRNA 3’ fragments are biochemically distinct from the tRNA halves produced transiently in response to stress. Notably, the end positions of Twi12-bound tRNA 3' fragments precisely match RNAs detected in total small RNA of mouse embryonic stem cells and human cancer cells. Our studies demonstrate unanticipated evolutionary conservation of mature tRNA processing to tRNA-fragment small RNAs.
Project description:Transplantation of ex vivo expanded limbal stem cells (LSC) is the main treatment for limbal stem cell deficiency though the clinical problem of donor tissues shortage. Recently, as the development of tissue engineering, embryonic stem cells (ESC) derived corneal epithelial-like cells (ESC-CEC) has become a new direction to this issue.Our group successfully induced ESC into corneal epithelial-like cells, and in the present study we explored various aspects of physiological properties of ESC-CEC. The experiment included three samples: hES, the human embryonic stem cell line H1, RA_SB, the corneal epithelial-like cells derived from hES by differentiation with RA and SB, epithelial_cell, the primary human limbal stem cells from cadaver eyes. hES, the human embryonic stem cell line H1, RA_SB, the corneal epithelial-like cells derived from hES by differentiation with RA and SB, epithelial_cell, the primary human limbal stem cells from cadaver eyes.
Project description:Argonaute/Piwi proteins associate with small RNAs that typically provide sequence specificity for RNP function in gene and genome regulation. Here we show that Twi12, a Tetrahymena Piwi protein essential for growth, is loaded with mature tRNA fragments. The tightly bound ~18-22 nt tRNA 3M-bM-^@M-^Y fragments are biochemically distinct from the tRNA halves produced transiently in response to stress. Notably, the end positions of Twi12-bound tRNA 3' fragments precisely match RNAs detected in total small RNA of mouse embryonic stem cells and human cancer cells. Our studies demonstrate unanticipated evolutionary conservation of mature tRNA processing to tRNA-fragment small RNAs. Two libraries are analyzed here: sRNAs associated with slightly overexpressed ZZ-tagged Twi12 purified under native conditions (size range 15-34nt), and those associated after formaldehyde crosslinking (15-22nt).
Project description:Small non-coding RNAs (sncRNAs) are key molecules regulating gene expression. High-throughput RNA-seq greatly advanced sncRNA discovery; however, traditional cDNA library construction protocols generate biased sequencing results, in part due to RNA modifications that interfere with adapter ligation and reverse transcription processes, preventing the detection of sncRNAs bearing these modifications. Here, we present PANDORA-seq (Panoramic RNA Display by Overcoming RNA modification Aborted Sequencing), employing a combination of enzymatic treatments to remove key RNA modifications that block adapter ligation and reverse transcription during cDNA library construction. PANDORA-Seq enables the discovery of thousands of modified sncRNAs previously undetected, mostly tRNA-derived small RNAs (tsRNAs) and rRNA-derived small RNAs (rsRNAs), which are tissue/cell-specifically detected across mouse brain, liver, spleen, sperm, mouse and human embryonic stem cells, and HeLa cells. Moreover, PANDORA-Seq reveals dynamic changes of tsRNAs and rsRNAs during reprogramming of induced pluripotent stem cells (iPSCs), pointing to future investigations on their potential regulatory functions.
Project description:Small RNAs constitute a new and unanticipated layer of gene regulation present in the three domains of life. In plants, all organs are ultimately derived from a few pluripotent stem cells localized in specialized structures called apical meristems. The development of meristems involves a coordinated balance between undifferentiated growth and differentiation, a phenomenon requiring a tight regulation of gene expression. We used in vitro cultured embryogenic calli as a model to investigate the roles of meristem-associated small RNAs. Using high-throughput sequencing, we sequenced 20 million short reads with size of 18-30nt from rice undifferentiated and differentiated calli. We confirmed 50 known microRNA families, representing one third of annotated rice microRNAs. Using a specific computational pipeline for plant microRNA identification, we identified 24 novel microRNA families. Among them, 53 microRNA or microRNA* sequences appear to vary in expression between differentiated and undifferentiated calli, suggesting a role in meristem development. Our analysis also revealed a new class of plant small RNAs derived from 5' or 3' ends of mature tRNA analogous to the tRFs in human cancer cell. We independently verified the expression of these small RNAs from 5' end of mature tRNA using qRT-PCR. Examination of 2 different small RNA expression profilings in 2 developmental stages of meristems.
Project description:Purpose: High-throughput RNA sequencing has accelerated discovery of the complex regulatory roles of small RNAs, such those derived from tRNAs. Also recent advances in high-throughput RNA sequencing has revealed the complex RNA modification landscape and the complex role these nucleosides modifactions have in cell signalling, stem cell biology, development and cancer. The goal of this study is to establish how m5C-tRNA methylation and tRNA-derived small RNAs can affect stem cell fucntion in cancer. Methods: four replicates of tRNAs and RNA buisulphite sequencing of wild-type (WT) and NSun2 -/- mouse skin squamous tumours were generated by deep sequencing, using Illumina HiSeq platform. Results: Our analyses reveal that inhibition of post-transcriptional cytosine-5 methylation locks stem cells in this distinct translational inhibition programme that results in tumour progression but that also sentizes cancer cells to genotoxic stress. Transfer RNA (tRNA) sequencing and RNA Bisulphite sequencing of wild-type (WT) and NSun2 -/- mouse skin squamous tumours
Project description:Many small molecular compounds reported were involved in improving reprogramming efficiency during inducing pluripotent stem cells (iPSC) or maintain a blastocyst-like state in embryonic stem cells (ESC), including BIO, CHIR99021 (CHIR), and vitamin C et al. However, the knowledge about these small molecules regulating miRNAs in ESC was limited. To understand the role of miRNAs during small molecules induced ESC maintenance and gain an insight how these small molecules regulates miRNAs expression; we performed small RNA sequencing using Illumina HiSeq 2000 under the compounds treatment. Retinoic acid (RA), a stimulus molecule for cellular differentiation, is set as negative control. The data show the miRNAs regulated by BIO, CHIR, vitamin C and RA.