CRISPR/Cas9-mediated homology-directed repair (HDR) is used for error-free targeted knock-in of foreign donor DNA. However, the low efficiency of HDR-mediated knock-in hinders establishment of ...knock-in clones. Double-strand breaks (DSBs) induced by CRISPR/Cas9 are preferentially repaired by non-homologous end joining (NHEJ) or microhomology-mediated end joining (MMEJ) before HDR can occur, thereby preventing HDR-mediated knock-in. NHEJ/MMEJ also cause random integrations, which give rise to false-positive knock-in events, or silently disrupt the genome. In this study, we optimized an HDR-mediated knock-in method for mouse embryonic stem cells (mESCs). We succeeded in improving efficiency of HDR-mediated knock-in of a plasmid donor while almost completely suppressing NHEJ/MMEJ-based integration by combining in vivo-linearization of the donor plasmid, transient knockdown of DNA polymerase θ, and chemical inhibition of DNA-dependent protein kinase (DNA-PK) by M3814. This method also dramatically improved the efficiency of biallelic knock-in; at the Rosa26a locus, 95% of HDR-mediated knock-in clones were biallelic. We designate this method BiPoD (Biallelic knock-in assisted by Pol θ and DNA-PK inhibition). BiPoD achieved simultaneous efficient biallelic knock-in into two loci. BiPoD, therefore, enables rapid and easy establishment of biallelic knock-in mESC lines.
Marine organisms are a rich source of bioactive secondary metabolites. Although many marine natural products with bioactivities have been isolated, successful elucidation of their mechanisms of ...action remains limited. In this study, we prepared a probe molecule based on the marine cyclic peptide kapakahine A (
) by introducing a linker with an azide terminal group, which enables the introduction of fluorescent groups for the effective monitoring of subcellular localization, or coupling to affinity beads for the pull-down of target proteins. The results of LC/MS/MS measurements, ProteinPilot analysis, and Western blotting suggest that kapakahine A interacts with the mitochondrial inner membrane proteins PHB1, PHB2, and ANT2, which is consistent with the results of the subcellular localization analysis using a fluorescent probe.
A number of bioactive marine natural products have been isolated so far, but it is still difficult to disclose their modes of action. In this study, we prepared fluorescently labeled chemical probes ...from the cytotoxic marine cyclic peptides kapakahines A (
) and F (
) to visualize their localization as the first step of the study of their modes of action. We used fluorescent dyes
or
(a 1:1 mixture of
and
) whose terminal
-hydroxysuccinimide (NHS) group can react with the free amino groups of kapakahines. The fluorescently labeled kapakahine A (Kap A-5-FL,
) stained P388 murine leukemia cells and HeLa human cervical cancer cells, while cells treated with fluorescently labeled kapakahine F (Kap F-5-FL,
) only weakly stained them. Further analysis of the confocal images of the stained cells with higher magnification (×100) indicated the localization of Kap A-5-FL (
) in the cells. In this paper, we report the small-scale preparation and a new delivery method of fluorescent probes, as well as the application of these procedures to cell staining.
Two previously unreported onnamide analogs, 2
- and 6
-onnamides A (
and
), were isolated from the marine sponge
collected at Amami-Oshima Is., Kagoshima Prefecture, Japan. Structures of compounds
...and
were elucidated by spectral analysis. Structure-activity relationships (SARs) for effects on histone modifications and cytotoxicity against HeLa and P388 cells were characterized. The geometry in the polyene systems of onnamides affected the histone modification levels and cytotoxicity.
In Vivo Gold Complex Catalysis within Live Mice Tsubokura, Kazuki; Vong, Kenward K. H.; Pradipta, Ambara R. ...
Angewandte Chemie International Edition,
March 20, 2017, Letnik:
56, Številka:
13
Journal Article
Recenzirano
Metal complex catalysis within biological systems is largely limited to cell and bacterial systems. In this work, a glycoalbumin–AuIII complex was designed and developed that enables organ‐specific, ...localized propargyl ester amidation with nearby proteins within live mice. The targeted reactivity can be imaged through the use of Cy7.5‐ and TAMRA‐linked propargyl ester based fluorescent probes. This targeting system could enable the exploitation of other metal catalysis strategies for biomedical and clinical applications.
The first metal‐catalyzed reaction that proceeds within live mice is based on a targeting approach with glycans. Glycoalbumin–AuIII complexes can be accumulated in specific organs where they catalyze amide bond formation between a propargyl ester probe and amine groups on nearby proteins. The selective targeting was confirmed by whole body fluorescence imaging and analysis of dissected tissues.
Marine sponges are the most prolific marine sources for discovery of novel bioactive compounds. Sponge secondary metabolites are sought-after for their potential in pharmaceutical applications, and ...in the past, they were also used as taxonomic markers alongside the difficult and homoplasy-prone sponge morphology for species delineation (chemotaxonomy). The understanding of phylogenetic distribution and distinctiveness of metabolites to sponge lineages is pivotal to reveal pathways and evolution of compound production in sponges. This benefits the discovery rate and yield of bioprospecting for novel marine natural products by identifying lineages with high potential of being new sources of valuable sponge compounds. In this review, we summarize the current biochemical data on sponges and compare the metabolite distribution against a sponge phylogeny. We assess compound specificity to lineages, potential convergences, and suitability as diagnostic phylogenetic markers. Our study finds compound distribution corroborating current (molecular) phylogenetic hypotheses, which include yet unaccepted polyphyly of several demosponge orders and families. Likewise, several compounds and compound groups display a high degree of lineage specificity, which suggests homologous biosynthetic pathways among their taxa, which identifies yet unstudied species of this lineage as promising bioprospecting targets.
EGR2 is a zinc finger transcription factor that regulates myelination in the peripheral nervous system and T cell anergy. The transcriptional activity of EGR2 is known to be regulated by its ...co-activators and/or co-repressors. Although the activity of transcription factors is generally regulated not only by interactions with co-regulators but also posttranslational modifications including acetylation, little is known about posttranslational modifications of EGR2. Here we show that EGR2 is a novel acetylated protein. Through immunoblotting analyses using an antibody that specifically recognizes the acetylated form of EGR2, CBP and p300 were identified as acetyltransferases, while HDAC6, 10 and SIRT1 were identified as deacetylases of EGR2. Although the NuRD complex containing HDAC1 and HDAC2 is known to associate with EGR2, the present study suggests that acetylation of EGR2 is regulated independently of NuRD.
•EGR2 is a novel acetylated protein.•p300 and CBP act as acetyltransferases of EGR2.•HDAC6, HDAC10, and SIRT1 act as deacetylases of EGR2.
Chemical-induced dysregulation of DNA methylation during the fetal period is known to contribute to developmental disorders or increase the risk of certain diseases later in life. In this study, we ...developed an iGEM (iPS cell-based global epigenetic modulation) detection assay using human induced pluripotent stem (hiPS) cells that express a fluorescently labeled methyl-CpG-binding domain (MBD), which enables a high-throughput screening of epigenetic teratogens/mutagens. 135 chemicals with known cardiotoxicity and carcinogenicity were categorized according to the MBD signal intensity, which reflects the degree of nuclear spatial distribution/concentration of DNA methylation. Further biological characterization through machine-learning analysis that integrated genome-wide DNA methylation, gene expression profiling, and knowledge-based pathway analysis revealed that chemicals with hyperactive MBD signals strongly associated their effects on DNA methylation and expression of genes involved in cell cycle and development. These results demonstrated that our MBD-based integrated analytical system is a powerful framework for detecting epigenetic compounds and providing mechanism insights of pharmaceutical development for sustainable human health.
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