BACKGROUND: CRISPR-Cas9 gene-editing technology has facilitated the generation of knockout mice, providing an alternative to cumbersome and time-consuming traditional embryonic stem cell-based methods. An earlier study reported up to 16% efficiency in generating conditional knockout (cKO or floxed) alleles by microinjection of 2 single guide RNAs (sgRNA) and 2 single-stranded oligonucleotides as donors (referred herein as "two-donor floxing" method). RESULTS: We re-evaluate the two-donor method from a consortium of 20 laboratories across the world. The dataset constitutes 56 genetic loci, 17,887 zygotes, and 1718 live-born mice, of which only 15 (0.87%) mice contain cKO alleles. We subject the dataset to statistical analyses and a machine learning algorithm, which reveals that none of the factors analyzed was predictive for the success of this method. We test some of the newer methods that use one-donor DNA on 18 loci for which the two-donor approach failed to produce cKO alleles. We find that the one-donor methods are 10- to 20-fold more efficient than the two-donor approach. CONCLUSION: We propose that the two-donor method lacks efficiency because it relies on two simultaneous recombination events in cis, an outcome that is dwarfed by pervasive accompanying undesired editing events. The methods that use one-donor DNA are fairly efficient as they rely on only one recombination event, and the probability of correct insertion of the donor cassette without unanticipated mutational events is much higher. Therefore, one-donor methods offer higher efficiencies for the routine generation of cKO animal models.

• Klíčová slova
• CRISPR-Cas9, Conditional knockout mouse, Floxed allele, Homology-directed repair, Long single-stranded DNA, Machine learning, Mouse, Oligonucleotide, Reproducibility, Transgenesis,
• MeSH
• alely * MeSH
• blastocysta metabolismus   MeSH
• CRISPR-Cas systémy genetika   MeSH
• faktorová analýza statistická MeSH
• mikroinjekce MeSH
• myši knockoutované MeSH
• protein 2 vázající methyl-CpG genetika   metabolismus   MeSH
• protein Cas9 metabolismus   MeSH
• regresní analýza MeSH
• reprodukovatelnost výsledků MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• Mecp2 protein, mouse MeSH Prohlížeč
• protein 2 vázající methyl-CpG MeSH
• protein Cas9 MeSH

Knowledge on acute myeloid leukemia pathogenesis and treatment has progressed recently, but not enough to provide ideal management. Improving the prognosis of acute myeloid leukemia patients depends on advances in molecular biology for the detection of new therapeutic targets and the production of effective drugs. The CRISPR/Cas9 technology allows gene insertions and deletions and it is the first step in investigating the function of their encoded proteins. Thus, new experimental models have been developed and progress has been made in understanding protein metabolism, antitumor activity, leukemic cell maintenance, differentiation, growth, apoptosis, and self-renewal, the combined pathogenetic mechanisms involved in leukemogenesis. The CRISPR/Cas9 system is used to understand drug resistance and find solutions to overcome it. The therapeutic progress achieved using the CRISPR/Cas9 system is remarkable. FST gene removal inhibited acute myeloid leukemia cell growth. Lysine acetyltransferase gene deletion contributed to decreased proliferation rate, increased apoptosis, and favored differentiation of acute myelid leukemia cells carrying MLL-X gene fusions. The removal of CD38 gene from NK cells decreased NK fratricidal cells contributing to increased efficacy of new CD38 CAR-NK cells to target leukemic blasts. BCL2 knockout has synergistic effects with FLT3 inhibitors. Exportin 1 knockout is synergistic with midostaurin treatment in acute myeloid leukemia with FLT3-ITD mutation. Using the results of CRISPR/Cas9 libraries and technology application will allow us to get closer to achieving the goal of curing acute myeloid leukemia in the coming decades.

• Klíčová slova
• BCL2, CD38, CRISPR/Cas9, FLT3 inhibitors, IDH2, acute myeloid leukemia,
• MeSH
• akutní myeloidní leukemie * genetika   terapie   MeSH
• CRISPR-Cas systémy * genetika   MeSH
• inhibitory proteinkinas MeSH
• lidé MeSH
• mutace MeSH
• proliferace buněk MeSH
• technologie MeSH
• tyrosinkinasa 3 podobná fms MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• inhibitory proteinkinas MeSH
• tyrosinkinasa 3 podobná fms MeSH

BACKGROUND: Genome editing using CRISPR-Cas9 has become one of the basic methods of biological research over a short period of time. This recently discovered system of adaptive immunity of bacteria has been adapted to the needs of science and has become a valuable tool for DNA manipulation. Its simplicity and reliability have contributed to widespread use of the method. Genome editing refers to targeted modifications of genomic DNA with single base pair accuracy. CRISPR-Cas9 differs significantly from previous technologies in the simplicity of directing the enzyme to the target sequence. In the field of cancer research, CRISPR-Cas9 has enabled the development of a number of models for the study of carcinogenesis and drug testing. From a therapeutic point of view, CRISPR-Cas9 has been applied in the field of immunotherapy, especially in ex vivo genetic modifications of the T-cells of patients. AIM: Currently, several clinical trials are trying to verify the therapeutic potential of CRISPR-Cas9. Based on these studies, we have summarised the strategies used in the preparation of therapeutic tools useful in cancer therapy. CONCLUSION: CRISPR-Cas9 appears to be crucial in basic research, particularly in the study of the function of individual genes involved in carcinogenesis. However, it will still be necessary to optimise the efficacy, safety and specificity of CRISPR-Cas9 before it is used in clinical practice.

• Klíčová slova
• CRISPR-Cas9, clinical trial, immunother­apy,
• MeSH
• cílená molekulární terapie * MeSH
• CRISPR-Cas systémy * MeSH
• editace genu metody   MeSH
• genetická terapie metody   MeSH
• lidé MeSH
• nádory genetika   imunologie   terapie   MeSH
• prognóza MeSH
• T-lymfocyty imunologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The advent of CRISPR/Cas technology has revolutionized genome editing, offering simplicity, precision, and cost-effectiveness. While its application in biological control fungi has been limited, including the cosmopolitan fungus Metarhizium anisopliae, recent advancements show promise. However, integrating cas9 and selection-marker genes into fungal genomes poses challenges, including reduced efficiency, toxicity, and off-target effects. Besides, marker-free genetic engineering through a CRISPR recyclable system presents a viable solution, enabling efficient mutant generation without compromising fitness and virulence. This study pioneers the construction of marker-free strains of M. anisopliae using a CRISPR/Cas9 recyclable system. Precise deletion of albA and ku70, alongside gfp cassette insertion, confirms the system efficiency. This innovative approach holds significant potential for facilitating in-depth molecular studies, understanding their ecological roles in agricultural systems, and enhancing biocontrol efficacy against insect pests through genetic improvement.

• Klíčová slova
• AMA1 vector, Biological control, Entomopathogenic, Gene edition, Marker free,
• Publikační typ
• časopisecké články MeSH

Even though chemotherapy and immunotherapy emerged to limit continual and unregulated proliferation of cancer cells, currently available therapeutic agents are associated with high toxicity levels and low success rates. Additionally, ongoing multi-targeted therapies are limited only for few carcinogenesis pathways, due to continually emerging and evolving mutations of proto-oncogenes and tumor-suppressive genes. CRISPR/Cas9, as a specific gene-editing tool, is used to correct causative mutations with minimal toxicity, but is also employed as an adjuvant to immunotherapy to achieve a more robust immunological response. Some of the most critical limitations of the CRISPR/Cas9 technology include off-target mutations, resulting in nonspecific restrictions of DNA upstream of the Protospacer Adjacent Motifs (PAM), ethical agreements, and the lack of a scientific consensus aiming at risk evaluation. Currently, CRISPR/Cas9 is tested on animal models to enhance genome editing specificity and induce a stronger anti-tumor response. Moreover, ongoing clinical trials use the CRISPR/Cas9 system in immune cells to modify genomes in a target-specific manner. Recently, error-free in vitro systems have been engineered to overcome limitations of this gene-editing system. The aim of the article is to present the knowledge concerning the use of CRISPR Cas9 technique in targeting treatment-resistant cancers. Additionally, the use of CRISPR/Cas9 is aided as an emerging supplementation of immunotherapy, currently used in experimental oncology. Demonstrating further, applications and advances of the CRISPR/Cas9 technique are presented in animal models and human clinical trials. Concluding, an overview of the limitations of the gene-editing tool is proffered.

• Klíčová slova
• animal models, cancer, experimental oncology, genome editing,
• MeSH
• CRISPR-Cas systémy * MeSH
• editace genu * MeSH
• genetická terapie * MeSH
• imunoterapie adoptivní MeSH
• imunoterapie * MeSH
• individualizovaná medicína metody   MeSH
• klinické zkoušky jako téma MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• nádory etiologie   terapie   MeSH
• nemoc MeSH
• preklinické hodnocení léčiv MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Sturgeons also known as living fossils are facing threats to their survival due to overfishing and interference in natural habitats. Sterlet (Acipenser ruthenus) due to its rapid reproductive cycle and small body size can be used as a sterile host for surrogate production for late maturing and large sturgeon species. Dead end protein (dnd1) is essential for migration of Primordial Germ Cells (PGCs), the origin of all germ cells in developing embryos. Knockout or knockdown of dnd1 can be done in order to mismigrate PGCs. Previously we have used MO and UV for the aforementioned purpose, and in our present study we have used CRISPR/Cas9 technology to knockout dnd1. No or a smaller number of PGCs were detected in crispants, and we also observed malformations in some CRISPR/Cas9 injected embryos. Furthermore, we compared three established methods to achieve sterility in sterlet, and we found higher embryo survival and hatching rates in CRISPR/Cas9, UV and MO, respectively.

• Klíčová slova
• Acipenser, PGCs, caviar, conservation, genome editing, morpholino oligonucleotide,
• Publikační typ
• časopisecké články MeSH

Cereal crops, including triticeae species (barley, wheat, rye), as well as edible cereals (wheat, corn, rice, oat, rye, sorghum), are significant suppliers for human consumption, livestock feed, and breweries. Over the past half-century, modern varieties of cereal crops with increased yields have contributed to global food security. However, presently cultivated elite crop varieties were developed mainly for optimal environmental conditions. Thus, it has become evident that taking into account the ongoing climate changes, currently a priority should be given to developing new stress-tolerant cereal cultivars. It is necessary to enhance the accuracy of methods and time required to generate new cereal cultivars with the desired features to adapt to climate change and keep up with the world population expansion. The CRISPR/Cas9 system has been developed as a powerful and versatile genome editing tool to achieve desirable traits, such as developing high-yielding, stress-tolerant, and disease-resistant transgene-free lines in major cereals. Despite recent advances, the CRISPR/Cas9 application in cereals faces several challenges, including a significant amount of time required to develop transgene-free lines, laboriousness, and a limited number of genotypes that may be used for the transformation and in vitro regeneration. Additionally, developing elite lines through genome editing has been restricted in many countries, especially Europe and New Zealand, due to a lack of flexibility in GMO regulations. This review provides a comprehensive update to researchers interested in improving cereals using gene-editing technologies, such as CRISPR/Cas9. We will review some critical and recent studies on crop improvements and their contributing factors to superior cereals through gene-editing technologies.

• Klíčová slova
• CRISPR/Cas, Cereals, Genome editing, Morphogenic genes, Speed breeding,
• MeSH
• CRISPR-Cas systémy genetika   MeSH
• editace genu * metody   MeSH
• geneticky modifikované rostliny genetika   MeSH
• genom rostlinný genetika   MeSH
• jedlá semena * genetika   MeSH
• lidé MeSH
• šlechtění rostlin metody   MeSH
• zemědělské plodiny genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Although microalgae have only recently been recognized as part of the plant and soil microbiome, their application as biofertilizers has a tradition in sustainable crop production. Under consideration of their ability to produce the plant growth-stimulating hormone cytokinin (CK), known to also induce pathogen resistance, we have assessed the biocontrol ability of CK-producing microalgae. All pro- and eukaryotic CK-producing microalgae tested were able to enhance the tolerance of tobacco against Pseudomonas syringae pv. tabaci (PsT) infection. Since Chlamydomonas reinhardtii (Cre) proved to be the most efficient, we functionally characterized its biocontrol ability. We employed the CRISPR-Cas9 system to generate the first knockouts of CK biosynthetic genes in microalgae. Specifically, we targeted Cre Lonely Guy (LOG) and isopentenyltransferase (IPT) genes, the key genes of CK biosynthesis. While Cre wild-type exhibits a strong protection, the CK-deficient mutants have a reduced ability to induce plant defence. The degree of protection correlates with the CK levels, with the IPT mutants showing less protection than the LOG mutants. Gene expression analyses showed that Cre strongly stimulates tobacco resistance through defence gene priming. This study functionally verifies that Cre primes defence responses with CK, which contributes to the robustness of the effect. This work contributes to elucidate microalgae-mediated plant defence priming and identifies the role of CKs. In addition, these results underscore the potential of CK-producing microalgae as biologicals in agriculture by combining biofertilizer and biocontrol ability for sustainable and environment-friendly crop management.

• MeSH
• Chlamydomonas reinhardtii * genetika   metabolismus   MeSH
• CRISPR-Cas systémy * MeSH
• cytokininy * metabolismus   MeSH
• mutace MeSH
• nemoci rostlin * mikrobiologie   imunologie   genetika   MeSH
• odolnost vůči nemocem * genetika   MeSH
• Pseudomonas syringae patogenita   fyziologie   MeSH
• tabák * genetika   mikrobiologie   imunologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytokininy * MeSH

Although different genome editing tools have been around for decades, the recent emergence of cheap, quick, and accessible CRISPR/Cas9 technology has led to a revolution in this field. The technique has the potential to transform medicine from curative into preventive using a gene therapy. An application of genome editing has proven to be effective for both genetic and non-genetic (e.g. infectious) diseases. However, cancer and rare diseases treatment is at the forefront of interest. Concurrently, the legal and ethical frameworks should be discussed, especially as the technology moves towards a modification of the germ cells or embryos. In addition to a precise molecular genetic diagnosis and choosing the best gene therapy approach for a particular individual, an attention should also be paid to the impacts on the entire human population and the next generations. In this review, we summarize the most important applications of CRISPR/Cas9 technology in the field of medicine. Some interesting results from recent years are presented in the context of used approaches and importance for the future developments in medicine. Finally, ethical and legal conditions in relation to different gene editing applications are discussed.

• Klíčová slova
• gene drive, gene therapy CRISPR/Cas9., genome editing,
• MeSH
• CRISPR-Cas systémy * MeSH
• editace genu * MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Agrobacterium-mediated transformation is one of the most commonly used genetic transformation method that involves transfer of foreign genes into target plants. Agroinfiltration, an Agrobacterium-based transient approach and the breakthrough discovery of CRISPR/Cas9 holds trending stature to perform targeted and efficient genome editing (GE). The predominant feature of agroinfiltration is the abolishment of Transfer-DNA (T-DNA) integration event to ensure fewer biosafety and regulatory issues besides showcasing the capability to perform transcription and translation efficiently, hence providing a large picture through pilot-scale experiment via transient approach. The direct delivery of recombinant agrobacteria through this approach carrying CRISPR/Cas cassette to knockout the expression of the target gene in the intercellular tissue spaces by physical or vacuum infiltration can simplify the targeted site modification. This review aims to provide information on Agrobacterium-mediated transformation and implementation of agroinfiltration with GE to widen the horizon of targeted genome editing before a stable genome editing approach. This will ease the screening of numerous functions of genes in different plant species with wider applicability in future.

• Klíčová slova
• Agrobacterium, CRISPR/Cas9, genome editing, targeted site modification, transfer-DNA, transgene-free,
• MeSH
• Agrobacterium genetika   MeSH
• CRISPR-Cas systémy * MeSH
• editace genu metody   MeSH
• genom rostlinný * MeSH
• mutageneze MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné proteiny genetika   MeSH
• rostliny genetika   metabolismus   MeSH
• transformace genetická MeSH
• zemědělské plodiny genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• rostlinné proteiny MeSH