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Author

Botao Liu

Other affiliations: Cornell University
Bio: Botao Liu is an academic researcher from University of Massachusetts Medical School. The author has contributed to research in topics: Ribosome profiling & Translation (biology). The author has an hindex of 12, co-authored 20 publications receiving 1332 citations. Previous affiliations of Botao Liu include Cornell University.

Papers
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Journal ArticleDOI
TL;DR: Global translation initiation sequencing is presented, applying in parallel the ribosome E-site translation inhibitors lactimidomycin and cycloheximide to achieve simultaneous detection of both initiation and elongation events on a genome-wide scale.
Abstract: Understanding translational control in gene expression relies on precise and comprehensive determination of translation initiation sites (TIS) across the entire transcriptome. The recently developed ribosome-profiling technique enables global translation analysis, providing a wealth of information about both the position and the density of ribosomes on mRNAs. Here we present an approach, global translation initiation sequencing, applying in parallel the ribosome E-site translation inhibitors lactimidomycin and cycloheximide to achieve simultaneous detection of both initiation and elongation events on a genome-wide scale. This approach provides a view of alternative translation initiation in mammalian cells with single-nucleotide resolution. Systemic analysis of TIS positions supports the ribosome linear-scanning mechanism in TIS selection. The alternative TIS positions and the associated ORFs identified by global translation initiation sequencing are conserved between human and mouse cells, implying physiological significance of alternative translation. Our study establishes a practical platform for uncovering the hidden coding potential of the transcriptome and offers a greater understanding of the complexity of translation initiation.

545 citations

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TL;DR: It is reported that intracellular proteotoxic stress reduces global protein synthesis by halting ribosomes on transcripts during elongation, suggesting a dual role of molecular chaperones in facilitating polypeptide elongation and cotranslational folding.

244 citations

Journal ArticleDOI
TL;DR: In this article, the authors present quantitative translation initiation sequencing (QTI-seq), with which the initiating ribosomes can be profiled in real time at single-nucleotide resolution.
Abstract: Cells have evolved exquisite mechanisms to fine-tune the rate of protein synthesis in response to stress. Systemic mapping of start-codon positions and precise measurement of the corresponding initiation rate would transform our understanding of translational control. Here we present quantitative translation initiation sequencing (QTI-seq), with which the initiating ribosomes can be profiled in real time at single-nucleotide resolution. Resultant initiation maps not only delineated variations of start-codon selection but also highlighted a dynamic range of initiation rates in response to nutrient starvation. The integrated data set provided unique insights into principles of alternative translation and mechanisms controlling different aspects of translation initiation. With RiboTag mice, QTI-seq permitted tissue-specific profiling of initiating ribosomes in vivo. Liver cell-specific ribosome profiling uncovered a robust translational reprogramming of the proteasome system in fasted mice. Our findings illuminated the prevalence and dynamic nature of translational regulation pivotal to physiological adaptation in vivo.

207 citations

Journal ArticleDOI
TL;DR: A recent genome-wide study using ribosome profiling has revealed unprecedented proteome complexity and flexibility through alternative translation, raising intriguing questions about stress-induced translational reprogramming.
Abstract: Cell survival in changing environments requires appropriate regulation of gene expression, including translational control. Multiple stress signaling pathways converge on several key translation factors, such as eIF4F and eIF2, and rapidly modulate messenger RNA (mRNA) translation at both the initiation and the elongation stages. Repression of global protein synthesis is often accompanied with selective translation of mRNAs encoding proteins that are vital for cell survival and stress recovery. The past decade has seen significant progress in our understanding of translational reprogramming in part due to the development of technologies that allow the dissection of the interplay between mRNA elements and corresponding binding proteins. Recent genome-wide studies using ribosome profiling have revealed unprecedented proteome complexity and flexibility through alternative translation, raising intriguing questions about stress-induced translational reprogramming. Many surprises emerged from these studies, including wide-spread alternative translation initiation, ribosome pausing during elongation, and reversible modification of mRNAs. Elucidation of the regulatory mechanisms underlying translational reprogramming will ultimately lead to the development of novel therapeutic strategies for human diseases.

159 citations

Journal ArticleDOI
TL;DR: High-resolution ribosome profiling and transcriptomic analysis of aNSCs in parallel from wild-type and Fmr1 knockout mice revealed diverse gene expression changes at both mRNA and translation levels, and it was discovered that FMRP regulates mitochondrial mRNA expression and energy homeostasis.
Abstract: Fragile X syndrome (FXS) is caused by the loss of fragile X mental retardation protein (FMRP), an RNA binding protein whose deficiency impacts many brain functions, including differentiation of adult neural stem cells (aNSCs). However, the mechanism by which FMRP influences these processes remains unclear. Here, we performed ribosome profiling and transcriptomic analysis of aNSCs in parallel from wild-type and Fmr1 knockout mice. Our data revealed diverse gene expression changes at both mRNA and translation levels. Many mitosis and neurogenesis genes were dysregulated primarily at the mRNA level, while numerous synaptic genes were mostly dysregulated at the translation level. Translational "buffering", whereby changes in ribosome association with mRNA are compensated by alterations in RNA abundance, was also evident. Knockdown of NECDIN, an FMRP-repressed transcriptional factor, rescued neuronal differentiation. In addition, we discovered that FMRP regulates mitochondrial mRNA expression and energy homeostasis. Thus, FMRP controls diverse transcriptional and posttranscriptional gene expression programs critical for neural differentiation.

72 citations


Cited by
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Journal ArticleDOI
TL;DR: This Review describes special events in the lifetimes of lncRNAs — before, during and after transcription — and discusses how these events ultimately shape the unique characteristics and functional roles of lNCRNAs.
Abstract: Long non-coding RNAs (lncRNAs) are a diverse class of RNAs that engage in numerous biological processes across every branch of life. Although initially discovered as mRNA-like transcripts that do not encode proteins, recent studies have revealed features of lncRNAs that further distinguish them from mRNAs. In this Review, we describe special events in the lifetimes of lncRNAs - before, during and after transcription - and discuss how these events ultimately shape the unique characteristics and functional roles of lncRNAs.

2,568 citations

Journal ArticleDOI
04 Jun 2015-Cell
TL;DR: In a unified mechanism of m(6)A-based regulation in the cytoplasm, YTHDF2-mediated degradation controls the lifetime of target transcripts, whereasYTHDF1-mediated translation promotion increases translation efficiency, ensuring effective protein production from dynamic transcripts that are marked by m( 6)A.

2,179 citations

Journal ArticleDOI
TL;DR: This work presents a census of 1,542 manually curated RBPs that are analysed for their interactions with different classes of RNA, their evolutionary conservation, their abundance and their tissue-specific expression, a critical step towards the comprehensive characterization of proteins involved in human RNA metabolism.
Abstract: Post-transcriptional gene regulation (PTGR) concerns processes involved in the maturation, transport, stability and translation of coding and non-coding RNAs. RNA-binding proteins (RBPs) and ribonucleoproteins coordinate RNA processing and PTGR. The introduction of large-scale quantitative methods, such as next-generation sequencing and modern protein mass spectrometry, has renewed interest in the investigation of PTGR and the protein factors involved at a systems-biology level. Here, we present a census of 1,542 manually curated RBPs that we have analysed for their interactions with different classes of RNA, their evolutionary conservation, their abundance and their tissue-specific expression. Our analysis is a critical step towards the comprehensive characterization of proteins involved in human RNA metabolism.

1,479 citations

Journal ArticleDOI
TL;DR: This study reports that N6-methyladenosine (m6A), the most abundant base modification of RNA, promotes efficient initiation of protein translation from circRNAs in human cells and suggests a role of circRNA-derived proteins in cellular responses to environmental stress.
Abstract: Extensive pre-mRNA back-splicing generates numerous circular RNAs (circRNAs) in human transcriptome. However, the biological functions of these circRNAs remain largely unclear. Here we report that N6-methyladenosine (m6A), the most abundant base modification of RNA, promotes efficient initiation of protein translation from circRNAs in human cells. We discover that consensus m6A motifs are enriched in circRNAs and a single m6A site is sufficient to drive translation initiation. This m6A-driven translation requires initiation factor eIF4G2 and m6A reader YTHDF3, and is enhanced by methyltransferase METTL3/14, inhibited by demethylase FTO, and upregulated upon heat shock. Further analyses through polysome profiling, computational prediction and mass spectrometry reveal that m6A-driven translation of circRNAs is widespread, with hundreds of endogenous circRNAs having translation potential. Our study expands the coding landscape of human transcriptome, and suggests a role of circRNA-derived proteins in cellular responses to environmental stress.

1,244 citations

Journal ArticleDOI
TL;DR: It is found that METTL3 promotes translation of certain mRNAs including epidermal growth factor receptor (EGFR) and the Hippo pathway effector TAZ in human cancer cells.

1,035 citations