scholarly journals Computational correction of off-targeting for CRISPR-Cas9 essentiality screens

2019 ◽  
Author(s):  
Alexendar R. Perez ◽  
Laura Sala ◽  
Richard K. Perez ◽  
Joana A. Vidigal

Off-target cleavage by Cas9 can confound measurements of cell proliferation/viability in CRISPR assays by eliciting a DNA-damage response that includes cell cycle arrest1-3. This gene-independent toxicity has been documented in large scale assays2-4 and shown to be a source of false-positives when libraries are populated by promiscuous guide RNAs (gRNAs)7. To address this, we developed CSC, a computational method to correct for the effect of specificity on gRNA depletion. We applied CSC to screening data from the Cancer Dependency Map and show that it significantly improves the specificity of CRISPR-Cas9 essentiality screens while preserving known gene essentialities even for genes targeted by highly pro-miscuous guides. We packaged CSC in a Python software to allow its seamless integration into current CRISPR analysis pipelines and improve the sensitivity of essentiality screens for repetitive genomic loci.

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Toshinori Ozaki ◽  
Akira Nakagawara ◽  
Hiroki Nagase

A proper DNA damage response (DDR), which monitors and maintains the genomic integrity, has been considered to be a critical barrier against genetic alterations to prevent tumor initiation and progression. The representative tumor suppressor p53 plays an important role in the regulation of DNA damage response. When cells receive DNA damage, p53 is quickly activated and induces cell cycle arrest and/or apoptotic cell death through transactivating its target genes implicated in the promotion of cell cycle arrest and/or apoptotic cell death such asp21WAF1,BAX, andPUMA. Accumulating evidence strongly suggests that DNA damage-mediated activation as well as induction of p53 is regulated by posttranslational modifications and also by protein-protein interaction. Loss of p53 activity confers growth advantage and ensures survival in cancer cells by inhibiting apoptotic response required for tumor suppression. RUNX family, which is composed of RUNX1, RUNX2, and RUNX3, is a sequence-specific transcription factor and is closely involved in a variety of cellular processes including development, differentiation, and/or tumorigenesis. In this review, we describe a background of p53 and a functional collaboration between p53 and RUNX family in response to DNA damage.


2017 ◽  
Author(s):  
Emma Haapaniemi ◽  
Sandeep Botla ◽  
Jenna Persson ◽  
Bernhard Schmierer ◽  
Jussi Taipale

AbstractWe report here that genome editing by CRISPR/Cas9 induces a p53-mediated DNA damage response and cell cycle arrest. Transient inhibition of p53 prevents this response, and increases the rate of homologous recombination more than five-fold. This provides a way to improve precision genome editing of normal cells, but warrants caution in using CRISPR for human therapies until the mechanism of the activation of p53 is elucidated.


Cell ◽  
2014 ◽  
Vol 157 (3) ◽  
pp. 565-579 ◽  
Author(s):  
Bao N. Puente ◽  
Wataru Kimura ◽  
Shalini A. Muralidhar ◽  
Jesung Moon ◽  
James F. Amatruda ◽  
...  

2012 ◽  
Vol 90 (6) ◽  
pp. 675-682 ◽  
Author(s):  
Xiaoming Yang ◽  
Xuezhong He ◽  
Zhengguan Yang ◽  
Esmaiel Jabbari

PER2 is a key mammalian circadian clock protein. It also has a tumor suppressive function. Down regulation of PER2 in the cultured cancer cells accelerates cell proliferation, while overexpression of PER2 inhibits cell growth and induces apoptosis. The Per2 mutant mice have a cancer prone phenotype and an altered DNA damage response. Here we report that PER2 regulates AKT activity. Cells with down-regulated PER2 expression have prolonged high levels of AKT T308 phosphorylation after growth factor stimulation or DNA damage. PER2 down-regulation delays DNA damage induced Chk2 activation and overrides DNA damage induced apoptosis and cell cycle arrest.


Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 845
Author(s):  
Liem Minh Phan ◽  
Abdol-Hossein Rezaeian

ATM is among of the most critical initiators and coordinators of the DNA-damage response. ATM canonical and non-canonical signaling pathways involve hundreds of downstream targets that control many important cellular processes such as DNA damage repair, apoptosis, cell cycle arrest, metabolism, proliferation, oxidative sensing, among others. Of note, ATM is often considered a major tumor suppressor because of its ability to induce apoptosis and cell cycle arrest. However, in some advanced stage tumor cells, ATM signaling is increased and confers remarkable advantages for cancer cell survival, resistance to radiation and chemotherapy, biosynthesis, proliferation, and metastasis. This review focuses on addressing major characteristics, signaling pathways and especially the diverse roles of ATM in cellular homeostasis and cancer development.


2021 ◽  
Vol 245 ◽  
pp. 03051
Author(s):  
Hanyi Jia

A mitotic cell that rests in permanent cell cycle arrest without the ability to divide is considered as a senescent cell. Cellular senescence is essential to limit the function of cells with heavy DNA damages. The lack of senescence is in favour of tumorigenesis, whereas the accumulation of senescent cells in tissues is likely to induce ageing and age-related pathologies on the organismal level. Understanding of cellular senescence is thus critical to both cancer and ageing studies. Senescence, essentially permanent cell cycle arrest, is one of the results of DNA damage response, such as the ataxia telangiectasia mutated and the ataxia telangiectasia and Rad3-related signaling pathways. In other cases, mild DNA damages can usually be repaired after DNA damage response, while the cells with heavy damages on DNA end in apoptosis. The damage to the special structure of telomere, however, prone to result in permanent cell cycle arrest after activation of DNA damage response. In fact, a few previous pieces of research on ageing have largely focused on telomere and considered it a primary contributor to different types of senescence. For instance, its reduction in length after each replication turns on a timer for replicative senescence, and its tandem repeats specific to binding proteins makes it susceptible to DNA damage from oxidative stress, and thus stress-induced premature senescence. In most of the senescent cells, the accumulation of biomarkers is found around the telomere which has either its tail structure disassembled or damage foci exposed on the tandem repeats. In this review, among several types of senescence, I will investigate two of the most common and widely discussed types in eukaryotic cells -replicative senescence and stress-induced premature senescence - in terms of their mechanism, relationship with telomere, and implication to organismal ageing.


Blood ◽  
2015 ◽  
Vol 126 (12) ◽  
pp. 1473-1482 ◽  
Author(s):  
Diamantis G. Konstantinidis ◽  
Katie M. Giger ◽  
Mary Risinger ◽  
Suvarnamala Pushkaran ◽  
Ping Zhou ◽  
...  

Key Points RhoA GTPase activates pMRLC and localizes to the site of midbody formation to regulate erythroblast cytokinesis. Cytokinesis failure in erythroblasts caused by RhoA deficiency triggers p53-mediated DNA-damage response, cell-cycle arrest, and apoptosis.


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