Posted by on July 15, 2020 2:04 am
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Nature:without the CRISPR system,a mitochondrial nucleotide editor

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1, nature: without the CRISPR system, the mitochondrial nucleotide editor

2020 7 on No. 8, from HHMI Joseph Mougous, Harvard University’s David Liu and Massachusetts General Hospital, Vamsi Mootha three laboratories in the journal Nature published a report entitled“A bacterial cytidine deaminase toxin contains CRISPR-free mitochondrial base editing”of the research paper, the discovery of a new non-CRISPR tool for this gene editing the ability to reach the cells of the second, smaller genome-mitochondria, which are mitochondrial DNA of the first accurate gene editor.

Fig. 1 | Non-toxic split-DddAtox halves reconstitute activity when co-localized on DNA in HEK293T cells.

researchers from a bacteria toxin, and the name of the DddA, it can catalyze the double-stranded DNA cytidine deaminase that. Researchers designed a non-toxic split-DddA semi-sub, and its binding to target DNA before there is no activity. split-DddA semi-sub, the transcription activation factor-like effect of the sub-array protein and a uracil glycosylase inhibitor of the Fusion produced no RNA-DddA-derived cytosine bases editor DdCBE, which can catalyze the human mitochondrial DNA in a CG to TA conversion, and has a high target specificity and product purity.

the researchers used DdCBE constructed of human cells and disease associated mitochondrial DNA mutation model, resulting in the rate of respiration and oxidative phosphorylation change. Does not contain the CRISPR of DdCBE can precisely manipulate mitochondrial DNA, rather than the elimination of mitochondrial DNA copy, which for Mitochondrial Disease Research and potential therapies have a broad meaning.

according to the introduction, bacterial toxins is a huge biochemical diversity of the Reserve can be re-used for biomedical applications. Such proteins include a class of deaminase superfamily of bacteria toxins, the members of which have been found in the gene editing technology in the application. Since past reports of cytidine deaminase on single-stranded nucleic acids on the run, so they are in base editing needed to unlock the double-stranded DNA, for example, by the CRISPR–Cas9 system.

to date, mitochondrial DNA bases Editing by guide RNA cannot enter the mitochondria of the obstruction. Therefore, the mitochondrial DNA of the operation is only limited by the designer of the nucleic acid enzyme of the mitochondrial genome of the targeted disruption.

(comments: powerful, without the CRISPR system, the mitochondria can precise gene editing

article source:

Beverly Y. Mok, Marcos H. de Moraes et al. A bacterial cytidine deaminase toxin contains CRISPR-free mitochondrial base editing. DOI: 10.1038/s41586-020-2477-4 Nature. The latest IF: 43.07

2, the Cell: a multifunctional biosensor reveals living cells, the trimeric G protein activity

2020 7 March 6,from the Boston University School of Medicine Mikel Garcia-Marcos research group in the “cell” magazine published entitled“ Revealing the Activity of Trimeric G-proteins in Live Cells with a Versatile Biosensor Design. ”The research papers, the use of multi-functional biosensor reveals living cells, the trimeric G protein activity.< br>

Fig. 2 | CELL screenshots

the researchers describe an optical biosensor, which can be used to detect living cells in Central Asia the second level resolution of the endogenous activity of the G protein. Using modular design principles, and researchThe staff is endogenous Gî ± -GTP and free Gßy(heterotrimeric G protein-the two active substances develop a gene encoding the non-molecular biosensor. Use this design to generate the different heterotrimeric G-protein or other G proteins such as Rho GTPases with specificity of the biosensor.

through the in many cases the application of the biosensor, including from the characterization of the cancer-associated G-protein mutants to the original generation of neurons in neurotransmitter signal transduction, the researchers further validated their versatility. Overall, this is a multifunction biosensor with high fidelity, temporal resolution and convenience, can be used to study living cells in the endogenous G protein activity.

according to the introduction, the heterotrimeric G protein Gαβγ is GPCR signal of the main transduction, which mediates numerous natural stimuli and therapeutic agents. However, there is currently no reliable method to directly measure the cells in the endogenous G protein activity.

(comment: this should be the first detectable probe a

article source:

Marcin Maziarz et al., Jong-Chan Park, Revealing the Activity of Trimeric G-proteins in Live Cells with a Versatile Biosensor Design. DOI: 10.1016/j. cell. 2020. 06. 020 , Cell: latest IF: 36.216

3, The Genome Biology: a new discovery of RNA polymerase with the chromatin three-dimensional structure

2020 7 November 2, from Peking University College of Life Sciences, the Quaternary of the male of the research group in the Genome Biology journal, published online, entitled“ Genome-wide analyses of chromatin interactions after the loss of Pol I, Pol II and Pol III, ”the research paper.< br>

in this study, the authors use the transformation-specific protein ubiquitination instantaneous degradation of the system degron, in conjunction with its laboratory earlier development of efficient chromatin higher-order structure analysis technologies BAT Hi-C ( Bridge linker-Alul-Tn5 Hi-C,the system set forth in RNA polymerase I/II/III (Pol I/II/III)to mammalian cells chromatin higher-order structure of direct and indirect regulation, and show that the chromatin three-dimensional structure is relatively stable.

Pol I/II/III as the whole gene expression process upstream of the core factors that are responsible for rRNA, mRNA, tRNA, etc. of the transcription, a process which requires the Coordination of a large number of transcription factors, which both May and chromatin structural proteins and non-coding RNA interactions to direct the organization of chromatin three-dimensional structure, it is possible through the transcription of the downstream effects of the indirect function. In order to answer these questions, the paper first use of the protein of the instantaneous drop technology, in mouse embryonic stem cells mESCs in the specific degradation of Pol I/II/III.

combined with the BAT to Hi-C technology, the system depicts RNA polymerase degradation before and after the chromatin three-dimensional structure of the pattern, and found that Pol I/II/III degradation of TADs and Compartments and other large-scale chromatin structure advanced structure limited impact. Interestingly, Pol II in the cell cycle of degradation does not prevent chromatin higher-order structure formation, indicating that transcription is not the three-dimensional chromatin structure in the establishment of the necessary.

Fig 3. The protein transient degradation of the system and the BAT Hi-C workflow

combined with more accurate chromatin structure analysis techniques HiChIP, OCEAN-C, the authors found that Pol II-specific degradation of the small-scale chromatin structure affect the more significant, respectively, by analysis of Pol I/II/III degradation before and after the high-enrichment zone of the structural changes found in the Pol I/II/III in the maintenance of the local fine chromatin structure plays a certain role.

then at different time points in the degradation of Pol II processing, the observed long-time Pol II degradation(>6 hr will change the chromatin openness and Cohesin proteins in chromatin binding, thus indicating that Pol II may be indirect regulation of chromatin higher-order structure.

in summary, the present work is a systematic description of the mammalian cells, RNA polymerase I/II/III (Pol I/II/III)for the maintenance of chromatin three-dimensional structure of relatively stable played a direct and indirect regulatory role, for the analysis of gene transcription and���Color quality of three-dimensional structure of the relationship between the two provides a more accurate basis for the study of other factors on the chromatin higher-order structure of the regulation provides a new way of thinking.

Fig 4. Pol I/II/III degradation of the respective high-enriched region of the sperm chromatin structure caused by the impact

(comments: to learn the

article source:

Yongpeng Jiang, Jie Huang et al, Genome-wide analyses of chromatin interactions after the loss of Pol I, Pol II, and Pol III. DOI: 10.1186/s13059-020-02067-3, Genome Biology

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Published at Wed, 15 Jul 2020 06:02:44 +0000