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Abstract
Understanding the functional effects of DNA sequence variants is of critical importance for studies of basic biology, evolution, and medical genetics; however, measuring these effects in a high-throughput manner is a major challenge. One promising avenue is precise editing with the CRISPR-Cas9 system, which allows for generation of DNA double-strand breaks (DSBs) at genomic sites matching the targeting sequence of a guide RNA (gRNA). Recent studies have used CRISPR libraries to generate many frameshift mutations genome wide through faulty repair of CRISPR-directed breaks by nonhomologous end joining (NHEJ) 1 . Here, we developed a CRISPR-library-based approach for highly efficient and precise genome-wide variant engineering. We used our method to examine the functional consequences of premature-termination codons (PTCs) at different locations within all annotated essential genes in yeast. We found that most PTCs were highly deleterious unless they occurred close to the 3' end of the gene and did not affect an annotated protein domain. Unexpectedly, we discovered that some putatively essential genes are dispensable, whereas others have large dispensable regions. This approach can be used to profile the effects of large classes of variants in a high-throughput manner.
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Affiliation(s)
- Meru J Sadhu
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA.
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA, USA.
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Joshua S Bloom
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA.
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA, USA.
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Laura Day
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jake J Siegel
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Sriram Kosuri
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Leonid Kruglyak
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA.
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA, USA.
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, Los Angeles, CA, USA.
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Lee JY, Khaing ZZ, Siegel JJ, Schmidt CE. Surface modification of neural electrodes with pyrrole-hyaluronic acid conjugate to attenuate reactive astrogliosis in vivo. RSC Adv 2015; 5:39228-39231. [PMID: 35528963 PMCID: PMC9075707 DOI: 10.1039/c5ra03294f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023] Open
Abstract
Surface of neural probes were electrochemically modified with a non-cell adhesive and biocompatible conjugate, pyrrole-hyaluronic acid (PyHA), to reduce reactive astrogliosis. Poly(PyHA)-modified wire electrodes were implanted into rat motor cortices for three weeks and were found to markedly reduce the expression of glial fibrillary acidic protein compared to uncoated electrodes.
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Affiliation(s)
- J Y Lee
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
- School of Materials Science and Engineering, Gwangju Institute of Science and Engineering, Gwangju, South Korea
| | - Z Z Khaing
- Department of Biomedical Engineering, The University of Florida at Gainesville, Gainesville, FL, USA
| | - J J Siegel
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX, USA
| | - C E Schmidt
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
- Department of Biomedical Engineering, The University of Florida at Gainesville, Gainesville, FL, USA
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3
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Abstract
Deviation from a balanced genome by either gain or loss of entire chromosomes is generally tolerated poorly in all eukaryotic systems studied to date. Errors in mitotic or meiotic cell division lead to aneuploidy, which places a burden of additional or insufficient gene products from the missegregated chromosomes on the daughter cells. The burden of aneuploidy often manifests itself as impaired fitness of individual cells and whole organisms, in which abnormal development is also characteristic. However, most human cancers, noted for their rapid growth, also display various levels of aneuploidy. Here we discuss the detrimental, potentially beneficial, and sometimes puzzling effects of aneuploidy on cellular and organismal fitness and tissue function as well as its role in diseases such as cancer and neurodegeneration.
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Affiliation(s)
- Jake J Siegel
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Tang YC, Williams BR, Siegel JJ, Amon A. Identification of aneuploidy-selective antiproliferation compounds. Cell 2011; 144:499-512. [PMID: 21315436 PMCID: PMC3532042 DOI: 10.1016/j.cell.2011.01.017] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 11/22/2010] [Accepted: 01/17/2011] [Indexed: 10/18/2022]
Abstract
Aneuploidy, an incorrect chromosome number, is a hallmark of cancer. Compounds that cause lethality in aneuploid, but not euploid, cells could therefore provide new cancer therapies. We have identified the energy stress-inducing agent AICAR, the protein folding inhibitor 17-AAG, and the autophagy inhibitor chloroquine as exhibiting this property. AICAR induces p53-mediated apoptosis in primary mouse embryonic fibroblasts (MEFs) trisomic for chromosome 1, 13, 16, or 19. AICAR and 17-AAG, especially when combined, also show efficacy against aneuploid human cancer cell lines. Our results suggest that compounds that interfere with pathways that are essential for the survival of aneuploid cells could serve as a new treatment strategy against a broad spectrum of human tumors.
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Affiliation(s)
- Yun-Chi Tang
- David H. Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
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Gagliardo A, Ioalè P, Odetti F, Bingman VP, Siegel JJ, Vallortigara G. Hippocampus and homing in pigeons: left and right hemispheric differences in navigational map learning. Eur J Neurosci 2001; 13:1617-24. [PMID: 11328355 DOI: 10.1046/j.0953-816x.2001.01522.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
One-month-old, inexperienced homing pigeons, prior to any opportunity to learn a navigational map, were subjected to either right or left unilateral ablation of the hippocampal formation (HF). These pigeons were then held together with a group of age-matched control birds in an outdoor aviary, where they were kept for about 3 months with the opportunity to learn a navigational map. When subsequently tested for navigational map learning at about 4 months of age posthatching, control and right HF-ablated pigeons were equally good at orienting homeward from distant, unfamiliar locations, indicating successful navigational map learning. By contrast, left HF-ablated pigeons were impaired in orienting homeward, indicating a failure to learn a navigational map. Interestingly, both right and left HF-ablated pigeons displayed impaired homing performance relative to controls. These results suggest that different aspects of homing pigeon navigation may be lateralized to different hemispheres, and in particular, the HF of the different hemispheres. The left HF appears critical for navigational map learning, i.e. determining an approximate direction home from distant, unfamiliar locations. The right HF, and possibly the left HF as well, appear to play an important role in local navigation near the loft, which is likely based on familiar landmarks.
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Affiliation(s)
- A Gagliardo
- Dipartimento di Etologia, Ecologia ed Evoluzione, Università di Pisa, Via Volta 6, I-56126 Pisa, Italy.
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Bingman VP, Able KP, Siegel JJ. Hippocampal lesions do not impair the geomagnetic orientation of migratory savannah sparrows. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1999; 185:577-81. [PMID: 10633558 DOI: 10.1007/s003590050418] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The avian hippocampal formation is known to participate in naturally occurring spatial behavior such as homing in pigeons and cache recovery in food storing passerines, but its participation in the often spectacular migrations of birds remains uncertain. As a first investigation into the possible role of hippocampal formation in migration, the effect of hippocampal formation lesions on the geomagnetic migratory orientation of Savannah sparrows was examined. When tested indoors, hippocampal formation-lesioned sparrows were able to orient in an appropriate migratory direction indicating no necessary role for hippocampal formation in geomagnetic migratory orientation. However, hippocampal formation-lesioned birds displayed significantly less migratory (nocturnal) activity, a result that inspires further study.
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Affiliation(s)
- V P Bingman
- Department of Psychology, Bowling Green State University, OH 43403, USA.
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