scholarly journals Structural Contributions to Hydrodynamic Diameter for Quantum Dots Optimized for Live-Cell Single-Molecule Tracking

2018 ◽  
Vol 122 (30) ◽  
pp. 17406-17412 ◽  
Author(s):  
Janet Y. Sheung ◽  
Pinghua Ge ◽  
Sung Jun Lim ◽  
Sang Hak Lee ◽  
Andrew M. Smith ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Single Molecule ◽  
Live Cell ◽  
Hydrodynamic Diameter ◽  
Single Molecule Tracking

scholarly journals Live-cell single-molecule tracking reveals co-recognition of H3K27me3 and DNA targets polycomb Cbx7-PRC1 to chromatin

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Chao Yu Zhen ◽  
Roubina Tatavosian ◽  
Thao Ngoc Huynh ◽  
Huy Nguyen Duc ◽  
Raibatak Das ◽  
...  
Keyword(s):  
Single Molecule ◽  
Molecular Mechanisms ◽  
Histone H3 ◽  
Live Cell ◽  
Disease Pathogenesis ◽  
Single Molecule Tracking ◽  
Cooperation Mechanism ◽  
Functional Dna ◽  
Biochemical Analyses ◽  
Prevailing View

The Polycomb PRC1 plays essential roles in development and disease pathogenesis. Targeting of PRC1 to chromatin is thought to be mediated by the Cbx family proteins (Cbx2/4/6/7/8) binding to histone H3 with a K27me3 modification (H3K27me3). Despite this prevailing view, the molecular mechanisms of targeting remain poorly understood. Here, by combining live-cell single-molecule tracking (SMT) and genetic engineering, we reveal that H3K27me3 contributes significantly to the targeting of Cbx7 and Cbx8 to chromatin, but less to Cbx2, Cbx4, and Cbx6. Genetic disruption of the complex formation of PRC1 facilitates the targeting of Cbx7 to chromatin. Biochemical analyses uncover that the CD and AT-hook-like (ATL) motif of Cbx7 constitute a functional DNA-binding unit. Live-cell SMT of Cbx7 mutants demonstrates that Cbx7 is targeted to chromatin by co-recognizing of H3K27me3 and DNA. Our data suggest a novel hierarchical cooperation mechanism by which histone modifications and DNA coordinate to target chromatin regulatory complexes.

scholarly journals Lipid-Specific Labeling of Enveloped Viruses with Quantum Dots for Single-Virus Tracking

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Li-Juan Zhang ◽  
Shaobo Wang ◽  
Li Xia ◽  
Cheng Lv ◽  
Hong-Wu Tang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Virus Infection ◽  
Quantum Dot ◽  
Single Molecule ◽  
Host Cells ◽  
Single Molecule Tracking ◽  
Enveloped Viruses ◽  
Single Virus Tracking ◽  
Labeling Method

ABSTRACT Quantum dots (QDs) possess optical properties of superbright fluorescence, excellent photostability, narrow emission spectra, and optional colors. Labeled with QDs, single molecules/viruses can be rapidly and continuously imaged for a long time, providing more detailed information than when labeled with other fluorophores. While they are widely used to label proteins in single-molecule-tracking studies, QDs have rarely been used to study virus infection, mainly due to a lack of accepted labeling strategies. Here, we report a general method to mildly and readily label enveloped viruses with QDs. Lipid-biotin conjugates were used to recognize and mark viral lipid membranes, and streptavidin-QD conjugates were used to light them up. Such a method allowed enveloped viruses to be labeled in 2 h with specificity and efficiency up to 99% and 98%, respectively. The intact morphology and the native infectivity of viruses were preserved. With the aid of this QD labeling method, we lit wild-type and mutant Japanese encephalitis viruses up, tracked their infection in living Vero cells, and found that H144A and Q258A substitutions in the envelope protein did not affect the virus intracellular trafficking. The lipid-specific QD labeling method described in this study provides a handy and practical tool to readily “see” the viruses and follow their infection, facilitating the widespread use of single-virus tracking and the uncovering of complex infection mechanisms. IMPORTANCE Virus infection in host cells is a complex process comprising a large number of dynamic molecular events. Single-virus tracking is a versatile technique to study these events. To perform this technique, viruses must be fluorescently labeled to be visible to fluorescence microscopes. The quantum dot is a kind of fluorescent tag that has many unique optical properties. It has been widely used to label proteins in single-molecule-tracking studies but rarely used to study virus infection, mainly due to the lack of an accepted labeling method. In this study, we developed a lipid-specific method to readily, mildly, specifically, and efficiently label enveloped viruses with quantum dots by recognizing viral envelope lipids with lipid-biotin conjugates and recognizing these lipid-biotin conjugates with streptavidin-quantum dot conjugates. It is not only applicable to normal viruses, but also competent to label the key protein-mutated viruses and the inactivated highly virulent viruses, providing a powerful tool for single-virus tracking.

scholarly journals Structural Contributions to Hydrodynamic Size of Quantum Dots for In-Vivo Single Molecule Tracking

2019 ◽  
Vol 116 (3) ◽  
pp. 175a
Author(s):  
Janet Y. Sheung ◽  
Pinghua Ge ◽  
Sung Jun Lim ◽  
Sang Hak Lee ◽  
Andrew Smith ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Single Molecule ◽  
Hydrodynamic Size ◽  
Single Molecule Tracking

scholarly journals Correction: Live cell single molecule tracking and localization microscopy of bioorthogonally labeled plasma membrane proteins

Nanoscale ◽  
2020 ◽  
Vol 12 (35) ◽  
pp. 18476-18477
Author(s):  
Andres I. König ◽  
Raya Sorkin ◽  
Ariel Alon ◽  
Dikla Nachmias ◽  
Kalyan Dhara ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Single Molecule ◽  
Live Cell ◽  
Plasma Membrane Proteins ◽  
Single Molecule Tracking ◽  
Localization Microscopy

Correction for ‘Live cell single molecule tracking and localization microscopy of bioorthogonally labeled plasma membrane proteins’ by Andres I. König et al., Nanoscale, 2020, 12, 3236–3248, DOI: 10.1039/C9NR08594G.

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