Project description:Mammals express thousands of long noncoding (lnc) RNAs, a few of which are shown to function in tissue development. However, the entire repertoire of lncRNAs and the extent to which they regulate biological processes in different tissues and species are not defined. Indeed, most lncRNAs are not conserved between species, raising questions about function. We used RNA-Seq to identify lncRNAs in primary murine fetal liver erythroblasts expressing the lineage marker TER119, megakaryocytes (CD41+) cultured from embryonic day (E) 14.5 murine fetal liver and megakaryocyte erythroid progenitors (MEPs) isolated from mouse bone marrow. We identified 683 and 594 polyadenylated lncRNAs expressed in red blood cell (erythroid) precursors of mice and humans, respectively. More than one half of erythroid lncRNAs are un-annotated, emphasizing the opportunity for new discovery through studies of specialized cell types. We analyzed the expression of these identified lncRNAs in several hematopoietic compartments using a custom microarray to identify erythroid-specific lncRNAs that were robustly expressed in both fetal liver and adult erythroid cells as targets for knockdown. Over 90% of fetal liver erythroid lncRNAs detected using RNA-seq were expressed in adult erythroblasts measured on the microarray. Analysis of the murine erythroid lncRNA transcriptome indicates that ~75% arise from promoters and 25% from enhancers, many of which are regulated by the key erythroid transcription factors GATA1 and SCL/TAL1. Erythroid lncRNA expression is largely conserved among 8 different mouse strains, yet only 15% of mouse lncRNAs are expressed in humans and vice versa, reflecting dramatically greater species-specificity than coding genes. We investigated potential functions of 21 relatively abundant erythroid-specific murine lncRNAs (both conserved and non-conserved) by RNA interference in primary mouse erythroid precursors, and identified 7 whose knockdown inhibited features of terminal erythroid maturation including cell size reduction and enucleation. Strikingly, at least 6 of the 7 lncRNAs have no detectable expression in human erythroblasts, demonstrating that lack of conservation between mammalian species does not predict lack of function. These results reflect marked evolutionary differences between protein-coding genes and lncRNAs and indicate that the latter exert tissue- and species-specific roles in development. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf A custom Agilent microarray was designed to interrogate expression levels of long noncoding RNAs identified using RNA-seq in several different hematopoietic progenitor and differentiated cell populations. LncRNA gene definitions and RNA-seq data used to identify long noncoding RNAs are deposited in GEO with the accession numbers GSE51667 and GSE40522 respectively. The Agilent eArray platform was used to customize the SurePrint G3 Mouse GE 8x60K microarray to add 3 custom-designed probes (60nt length) each against several categories of genes, namely pseudogene, genes with small RNA overlap, low stringency lncRNAs and high stringency lncRNAs . We interrogated 7 types of hematopoietic cells, HSC, CMP, MEP, GMP, early and late erythroblasts and granulocytes. Expression measurements were determined at least in duplicate for all samples and in triplicate for most samples.

Project description:Mammals express thousands of long noncoding (lnc) RNAs, a few of which are shown to function in tissue development. However, the entire repertoire of lncRNAs and the extent to which they regulate biological processes in different tissues and species are not defined. Indeed, most lncRNAs are not conserved between species, raising questions about function. We used RNA-Seq to identify lncRNAs in primary murine fetal liver erythroblasts expressing the lineage marker TER119, megakaryocytes (CD41+) cultured from embryonic day (E) 14.5 murine fetal liver and megakaryocyte erythroid progenitors (MEPs) isolated from mouse bone marrow. We identified 683 and 594 polyadenylated lncRNAs expressed in red blood cell (erythroid) precursors of mice and humans, respectively. More than one half of erythroid lncRNAs are un-annotated, emphasizing the opportunity for new discovery through studies of specialized cell types. We analyzed the expression of these identified lncRNAs in several hematopoietic compartments using a custom microarray to identify erythroid-specific lncRNAs that were robustly expressed in both fetal liver and adult erythroid cells as targets for knockdown. Over 90% of fetal liver erythroid lncRNAs detected using RNA-seq were expressed in adult erythroblasts measured on the microarray. Analysis of the murine erythroid lncRNA transcriptome indicates that ~75% arise from promoters and 25% from enhancers, many of which are regulated by the key erythroid transcription factors GATA1 and SCL/TAL1. Erythroid lncRNA expression is largely conserved among 8 different mouse strains, yet only 15% of mouse lncRNAs are expressed in humans and vice versa, reflecting dramatically greater species-specificity than coding genes. We investigated potential functions of 21 relatively abundant erythroid-specific murine lncRNAs (both conserved and non-conserved) by RNA interference in primary mouse erythroid precursors, and identified 7 whose knockdown inhibited features of terminal erythroid maturation including cell size reduction and enucleation. Strikingly, at least 6 of the 7 lncRNAs have no detectable expression in human erythroblasts, demonstrating that lack of conservation between mammalian species does not predict lack of function. These results reflect marked evolutionary differences between protein-coding genes and lncRNAs and indicate that the latter exert tissue- and species-specific roles in development. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf

Project description:Only a minuscule fraction of long non-coding RNAs (lncRNAs) are well characterized. The evolutionary history of lncRNAs can provide insights into their functionality, but comparative analyses have been precluded by our ignorance of lncRNAs in non-model organisms. Here, we use RNA sequencing to identify lncRNAs in eleven tetrapod species and we present the first large-scale evolutionary study of lncRNA repertoires and expression patterns. We identify ~11,000 primate- specific lncRNA families, which show evidence for selective constraint during recent evolution, and ~2,400 highly conserved lncRNAs (including ~400 genes that likely originated more than 300 million years ago). We find that lncRNAs, in particular ancient ones, are generally actively regulated and may predominantly function in embryonic development. lncRNA X-inactivation patterns reveal an extremely female-biased monotreme-specific lncRNA, which may partially compensate X-dosage in this lineage. Most lncRNAs evolve rapidly in terms of sequence and expression levels, but global patterns like tissue specificities are often conserved. We compared expression patterns of homologous lncRNA and protein-coding families across tetrapods to reconstruct an evolutionarily conserved co-expression network. This network, which surprisingly contains many lncRNA hubs, suggests potential functions for lncRNAs in fundamental processes like spermatogenesis or synaptic transmission, but also in more specific mechanisms such as placenta growth suppression through miRNA production. [Batch 1 and 2] To broaden our understanding of lncRNA evolution, we used an extensive RNA-seq dataset to establish lncRNA repertoires and homologous gene families in 11 tetrapod species. We analyzed the poly- adenylated transcriptomes of 8 organs (cortex/whole brain without cerebellum, cerebellum, heart, kidney, liver, placenta, ovary and testis) and 11 species (human, chimpanzee, bonobo, gorilla, orangutan, macaque, mouse, opossum, platypus, chicken and the frog Xenopus tropicalis), which shared a common ancestor ~370 millions of years (MY) ago. Our dataset included 47 strand-specific samples, which allowed us to confirm the orientation of gene predictions and to address the evolution of sense-antisense transcripts. See also GSE43721 (Soumillon et al, Cell Reports, 2013) for three strand-specific samples for mouse brain, liver and testis.

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Expression of novel long noncoding RNAs during erythro-megakaryopoiesis and GATA1-induced erythroid differentiation using RNA-seq

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