51
|
Lim J, Lee M, Son A, Chang H, Kim VN. mTAIL-seq reveals dynamic poly(A) tail regulation in oocyte-to-embryo development. Genes Dev 2016; 30:1671-82. [PMID: 27445395 PMCID: PMC4973296 DOI: 10.1101/gad.284802.116] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/28/2016] [Indexed: 12/04/2022]
Abstract
Here, Lim et al. report a new version of TAIL-seq (mRNA TAIL-seq [mTAIL-seq]) with enhanced sequencing depth for mRNAs (by ∼1000-fold compared with the previous version). Using their new methodology, the authors investigated mRNA tailing in Drosophila oocytes and embryos and demonstrated a relationship between poly(A) tail length and translational efficiency during egg activation. Eukaryotic mRNAs are subject to multiple types of tailing that critically influence mRNA stability and translatability. To investigate RNA tails at the genomic scale, we previously developed TAIL-seq, but its low sensitivity precluded its application to biological materials of minute quantity. In this study, we report a new version of TAIL-seq (mRNA TAIL-seq [mTAIL-seq]) with enhanced sequencing depth for mRNAs (by ∼1000-fold compared with the previous version). The improved method allows us to investigate the regulation of poly(A) tails in Drosophila oocytes and embryos. We found that maternal mRNAs are polyadenylated mainly during late oogenesis, prior to fertilization, and that further modulation occurs upon egg activation. Wispy, a noncanonical poly(A) polymerase, adenylates the vast majority of maternal mRNAs, with a few intriguing exceptions such as ribosomal protein transcripts. By comparing mTAIL-seq data with ribosome profiling data, we found a strong coupling between poly(A) tail length and translational efficiency during egg activation. Our data suggest that regulation of poly(A) tails in oocytes shapes the translatomic landscape of embryos, thereby directing the onset of animal development. By virtue of the high sensitivity, low cost, technical robustness, and broad accessibility, mTAIL-seq will be a potent tool to improve our understanding of mRNA tailing in diverse biological systems.
Collapse
Affiliation(s)
- Jaechul Lim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Mihye Lee
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Ahyeon Son
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Hyeshik Chang
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - V Narry Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| |
Collapse
|
52
|
Yuan K, Seller CA, Shermoen AW, O'Farrell PH. Timing the Drosophila Mid-Blastula Transition: A Cell Cycle-Centered View. Trends Genet 2016; 32:496-507. [PMID: 27339317 DOI: 10.1016/j.tig.2016.05.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 05/19/2016] [Accepted: 05/23/2016] [Indexed: 11/18/2022]
Abstract
At the mid-blastula transition (MBT), externally developing embryos refocus from increasing cell number to elaboration of the body plan. Studies in Drosophila reveal a sequence of changes in regulators of Cyclin:Cdk1 that increasingly restricts the activity of this cell cycle kinase to slow cell cycles during early embryogenesis. By reviewing these events, we provide an outline of the mechanisms slowing the cell cycle at and around the time of MBT. The perspectives developed should provide a guiding paradigm for the study of other MBT changes as the embryo transits from maternal control to a regulatory program centered on the expression of zygotic genes.
Collapse
Affiliation(s)
- Kai Yuan
- Department of Biophysics and Biochemistry, University of California San Francisco (UCSF), San Francisco, CA 94158, USA
| | - Charles A Seller
- Department of Biophysics and Biochemistry, University of California San Francisco (UCSF), San Francisco, CA 94158, USA
| | - Antony W Shermoen
- Department of Biophysics and Biochemistry, University of California San Francisco (UCSF), San Francisco, CA 94158, USA
| | - Patrick H O'Farrell
- Department of Biophysics and Biochemistry, University of California San Francisco (UCSF), San Francisco, CA 94158, USA.
| |
Collapse
|
53
|
Dallaire A, Simard MJ. The implication of microRNAs and endo-siRNAs in animal germline and early development. Dev Biol 2016; 416:18-25. [PMID: 27287880 DOI: 10.1016/j.ydbio.2016.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/31/2016] [Accepted: 06/06/2016] [Indexed: 01/13/2023]
Abstract
Germ cells provide maternal mRNAs that are stored in the oocyte, and later translated at a specific time of development. In this context, gene regulation depends mainly on post-transcriptional mechanisms that contribute to keep maternal transcripts in a stable and translationally silent state. In recent years, small non-coding RNAs, such as microRNAs have emerged as key post-transcriptional regulators of gene expression. microRNAs control the translation efficiency and/or stability of targeted mRNAs. microRNAs are present in animal germ cells and maternally inherited microRNAs are abundant in early embryos. However, it is not known how microRNAs control the stability and translation of maternal transcripts. In this review, we will discuss the implication of germline microRNAs in regulating animal oogenesis and early embryogenesis as well as compare their roles with endo-siRNAs, small RNA species that share key molecular components with the microRNA pathway.
Collapse
Affiliation(s)
- Alexandra Dallaire
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (Hôtel-Dieu de Québec), Quebec City, Québec, Canada G1R 2J6; Laval University Cancer Research Centre, Quebec City, Québec, Canada G1R 2J6
| | - Martin J Simard
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (Hôtel-Dieu de Québec), Quebec City, Québec, Canada G1R 2J6; Laval University Cancer Research Centre, Quebec City, Québec, Canada G1R 2J6.
| |
Collapse
|
54
|
The Drosophila prage Gene, Required for Maternal Transcript Destabilization in Embryos, Encodes a Predicted RNA Exonuclease. G3-GENES GENOMES GENETICS 2016; 6:1687-93. [PMID: 27172196 PMCID: PMC4889664 DOI: 10.1534/g3.116.028415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Egg activation, the transition of mature oocytes into developing embryos, is critical for the initiation of embryogenesis. This process is characterized by resumption of meiosis, changes in the egg's coverings and by alterations in the transcriptome and proteome of the egg; all of these occur in the absence of new transcription. Activation of the egg is prompted by ionic changes in the cytoplasm (usually a rise in cytosolic calcium levels) that are triggered by fertilization in some animals and by mechanosensitive cues in others. The egg's transcriptome is dramatically altered during the process, including by the removal of many maternal mRNAs that are not needed for embryogenesis. However, the mechanisms and regulators of this selective RNA degradation are not yet fully known. Forward genetic approaches in Drosophila have identified maternal-effect genes whose mutations prevent the transcriptome changes. One of these genes, prage (prg), was identified by Tadros et al. in a screen for mutants that fail to destabilize maternal transcripts. We identified the molecular nature of the prg gene through a combination of deficiency mapping, complementation analysis, and DNA sequencing of both extant prg mutant alleles. We find that prg encodes a ubiquitously expressed predicted exonuclease, consistent with its role in maternal mRNA destabilization during egg activation.
Collapse
|
55
|
Wessels HH, Imami K, Baltz AG, Kolinski M, Beldovskaya A, Selbach M, Small S, Ohler U, Landthaler M. The mRNA-bound proteome of the early fly embryo. Genome Res 2016; 26:1000-9. [PMID: 27197210 PMCID: PMC4937569 DOI: 10.1101/gr.200386.115] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 04/26/2016] [Indexed: 12/22/2022]
Abstract
Early embryogenesis is characterized by the maternal to zygotic transition (MZT), in which maternally deposited messenger RNAs are degraded while zygotic transcription begins. Before the MZT, post-transcriptional gene regulation by RNA-binding proteins (RBPs) is the dominant force in embryo patterning. We used two mRNA interactome capture methods to identify RBPs bound to polyadenylated transcripts within the first 2 h of Drosophila melanogaster embryogenesis. We identified a high-confidence set of 476 putative RBPs and confirmed RNA-binding activities for most of 24 tested candidates. Most proteins in the interactome are known RBPs or harbor canonical RBP features, but 99 exhibited previously uncharacterized RNA-binding activity. mRNA-bound RBPs and TFs exhibit distinct expression dynamics, in which the newly identified RBPs dominate the first 2 h of embryonic development. Integrating our resource with in situ hybridization data from existing databases showed that mRNAs encoding RBPs are enriched in posterior regions of the early embryo, suggesting their general importance in posterior patterning and germ cell maturation.
Collapse
Affiliation(s)
- Hans-Hermann Wessels
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
| | - Koshi Imami
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
| | - Alexander G Baltz
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
| | - Marcin Kolinski
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
| | | | - Matthias Selbach
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
| | - Stephen Small
- Department of Biology, New York University, New York, New York 10003, USA
| | - Uwe Ohler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany; Department of Biology, Humboldt University, 10115 Berlin, Germany
| | - Markus Landthaler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
| |
Collapse
|
56
|
Fernández-Alvarez AJ, Pascual ML, Boccaccio GL, Thomas MG. Smaug variants in neural and non-neuronal cells. Commun Integr Biol 2016; 9:e1139252. [PMID: 27195061 PMCID: PMC4857778 DOI: 10.1080/19420889.2016.1139252] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/02/2016] [Accepted: 01/04/2016] [Indexed: 10/25/2022] Open
Abstract
Mammalian Smaug1/Samd4a is an mRNA regulator involved in synapse plasticity and additional non-neuronal functions. Here we analyzed the expression of Smaug1/Samd4a variants and Smaug2/Samd4b in primary hippocampal neurons and non-neuronal cell lines. We found that multiple Smaug proteins are present in several mammalian cell lines, including a canonical full length Smaug1, a Smaug1 variant that lacks the third exon, termed ΔEIII, and Smaug2, the product of a highly homologous gene. These three major isoforms are expressed differentially along neuron development and form cytosolic bodies when transfected in cell lines. By using luciferase reporters, we found that the ΔEIII isoform, which lacks 10 amino acids in the sterile α motif involved in RNA binding, shows a RNA-binding capacity and repressor activity comparable to that of the full length Smaug1. These observations are an important groundwork for molecular studies of the Smaug post-transcriptional pathway, which is relevant to neuron development, mitochondrial function and muscle physiology in health and disease.
Collapse
Affiliation(s)
- Ana Julia Fernández-Alvarez
- Fundación Instituto Leloir, Buenos Aires, Argentina; Instituto de Investigaciones Bioquímicas Buenos Aires-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Malena Lucía Pascual
- Fundación Instituto Leloir, Buenos Aires, Argentina; Instituto de Investigaciones Bioquímicas Buenos Aires-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina; Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
| | - Graciela Lidia Boccaccio
- Fundación Instituto Leloir, Buenos Aires, Argentina; Instituto de Investigaciones Bioquímicas Buenos Aires-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina; Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
| | - María Gabriela Thomas
- Fundación Instituto Leloir, Buenos Aires, Argentina; Instituto de Investigaciones Bioquímicas Buenos Aires-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| |
Collapse
|