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Lyons EF, Devanneaux LC, Muller RY, Freitas AV, Meacham ZA, McSharry MV, Trinh VN, Rogers AJ, Ingolia NT, Lareau LF. Codon optimality modulates protein output by tuning translation initiation. bioRxiv 2023:2023.11.27.568910. [PMID: 38076849 PMCID: PMC10705293 DOI: 10.1101/2023.11.27.568910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The impact of synonymous codon choice on protein output has important implications for understanding endogenous gene expression and design of synthetic mRNAs. Previously, we used a neural network model to design a series of synonymous fluorescent reporters whose protein output in yeast spanned a seven-fold range corresponding to their predicted translation speed. Here, we show that this effect is not due primarily to the established impact of slow elongation on mRNA stability, but rather, that an active mechanism further decreases the number of proteins made per mRNA. We combine simulations and careful experiments on fluorescent reporters to argue that translation initiation is limited on non-optimally encoded transcripts. Using a genome-wide CRISPRi screen to discover factors modulating the output from non-optimal transcripts, we identify a set of translation initiation factors including multiple subunits of eIF3 whose depletion restored protein output of a non-optimal reporter. Our results show that codon usage can directly limit protein production, across the full range of endogenous variability in codon usage, by limiting translation initiation.
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Affiliation(s)
| | | | | | | | | | | | - Van N Trinh
- Department of Bioengineering, University of California, Berkeley
| | | | | | - Liana F Lareau
- Department of Molecular and Cell Biology
- California Institute for Quantitative Biosciences
- Department of Bioengineering, University of California, Berkeley
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2
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Thomas JD, Polaski JT, Feng Q, De Neef EJ, Hoppe ER, McSharry MV, Pangallo J, Gabel AM, Belleville AE, Watson J, Nkinsi NT, Berger AH, Bradley RK. RNA isoform screens uncover the essentiality and tumor-suppressor activity of ultraconserved poison exons. Nat Genet 2020; 52:84-94. [PMID: 31911676 PMCID: PMC6962552 DOI: 10.1038/s41588-019-0555-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 11/21/2019] [Indexed: 12/30/2022]
Abstract
While RNA-seq has enabled comprehensive quantification of alternative splicing, no correspondingly high-throughput assay exists for functionally interrogating individual isoforms. We describe pgFARM (paired guide RNAs for alternative exon removal), a CRISPR-Cas9-based method to manipulate isoforms independent of gene inactivation. This approach enabled rapid suppression of exon recognition in polyclonal settings to identify functional roles for individual exons, such as an SMNDC1 cassette exon that regulates pan-cancer intron retention. We generalized this method to a pooled screen to measure the functional relevance of 'poison' cassette exons, which disrupt their host genes' reading frames yet are frequently ultraconserved. Many poison exons were essential for the growth of both cultured cells and lung adenocarcinoma xenografts, while a subset had clinically relevant tumor-suppressor activity. The essentiality and cancer relevance of poison exons are likely to contribute to their unusually high conservation and contrast with the dispensability of other ultraconserved elements for viability.
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Affiliation(s)
- James D Thomas
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Jacob T Polaski
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Qing Feng
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Emma J De Neef
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Emma R Hoppe
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Maria V McSharry
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Joseph Pangallo
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Austin M Gabel
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Andrea E Belleville
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Jacqueline Watson
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Naomi T Nkinsi
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Alice H Berger
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
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Kwak JW, Laskowski J, Li HY, McSharry MV, Sippel TR, Bullock BL, Johnson AM, Poczobutt JM, Neuwelt AJ, Malkoski SP, Weiser-Evans MC, Lambris JD, Clambey ET, Thurman JM, Nemenoff RA. Complement Activation via a C3a Receptor Pathway Alters CD4 + T Lymphocytes and Mediates Lung Cancer Progression. Cancer Res 2017; 78:143-156. [PMID: 29118090 DOI: 10.1158/0008-5472.can-17-0240] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 06/12/2017] [Accepted: 11/01/2017] [Indexed: 11/16/2022]
Abstract
The complement cascade is a part of the innate immune system that acts primarily to remove pathogens and injured cells. However, complement activation is also peculiarly associated with tumor progression. Here we report mechanistic insights into this association in multiple immunocompetent orthotopic models of lung cancer. After tumor engraftment, we observed systemic activation of the complement cascade as reflected by elevated levels of the key regulator C3a. Notably, growth of primary tumors and metastases was both strongly inhibited in C3-deficient mice (C3-/- mice), with tumors undetectable in many subjects. Growth inhibition was associated with increased numbers of IFNγ+/TNFα+/IL10+ CD4+ and CD8+ T cells. Immunodepletion of CD4+ but not CD8+ T cells in tumor-bearing subjects reversed the inhibitory effects of C3 deletion. Similarly, antagonists of the C3a or C5a receptors inhibited tumor growth. Investigations using multiple tumor cell lines in the orthotopic model suggested the involvement of a C3/C3 receptor autocrine signaling loop in regulating tumor growth. Overall, our findings offer functional evidence that complement activation serves as a critical immunomodulator in lung cancer progression, acting to drive immune escape via a C3/C5-dependent pathway.Significance: This provocative study suggests that inhibiting complement activation may heighten immunotherapeutic responses in lung cancer, offering findings with immediate implications, given the existing clinical availability of complement antagonists. Cancer Res; 78(1); 143-56. ©2017 AACR.
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Affiliation(s)
- Jeff W Kwak
- Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | | | - Howard Y Li
- Department of Medicine, University of Colorado Denver, Aurora, Colorado.,Veterans Affairs Medical Center, Denver, Colorado
| | - Maria V McSharry
- Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Trisha R Sippel
- Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Bonnie L Bullock
- Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Amber M Johnson
- Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | | | | | | | - Mary C Weiser-Evans
- Department of Medicine, University of Colorado Denver, Aurora, Colorado.,Department of Pharmacology, University of Colorado Denver, Aurora, Colorado
| | - John D Lambris
- Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
| | - Eric T Clambey
- Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
| | - Joshua M Thurman
- Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Raphael A Nemenoff
- Department of Medicine, University of Colorado Denver, Aurora, Colorado. .,Department of Pharmacology, University of Colorado Denver, Aurora, Colorado
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