A5080687975- Microtubule and mitosis dynamics
- Genomics and Chromatin Dynamics
- Cellular Mechanics and Interactions
- Nuclear Structure and Function
- RNA Research and Splicing
- Micro and Nano Robotics
- Protist diversity and phylogeny
- Axon Guidance and Neuronal Signaling
- 3D Printing in Biomedical Research
- Microfluidic and Bio-sensing Technologies
- Cell Adhesion Molecules Research
- Cell Image Analysis Techniques
- Chromosomal and Genetic Variations
- Innovative Microfluidic and Catalytic Techniques Innovation
- AI in cancer detection
- RNA and protein synthesis mechanisms
- Photosynthetic Processes and Mechanisms
- Angiogenesis and VEGF in Cancer
- Image Processing and 3D Reconstruction
- Extracellular vesicles in disease
- Renal and related cancers
- Reproductive Biology and Fertility
- Genomics and Phylogenetic Studies
- Graph Theory and Algorithms
- Block Copolymer Self-Assembly
University of Wyoming
2015-2024
Wyoming Department of Education
2019-2024
Marine Biological Laboratory
2009-2022
University of North Carolina at Chapel Hill
2008-2010
University of Colorado Denver
2002-2008
University of Colorado Cancer Center
2003-2008
The mitotic spindle must function in cell types that vary greatly size, and its dimensions scale with the rapid, reductive divisions accompany early stages of development. mechanism responsible for this scaling is unclear, because uncoupling size from a developmental or cellular context has proven experimentally challenging. We combined microfluidic technology Xenopus egg extracts to characterize assembly within discrete, geometrically defined volumes cytoplasm. Reductions cytoplasmic...
When chromosomes are aligned and bioriented at metaphase, the elastic stretch of centromeric chromatin opposes pulling forces exerted on sister kinetochores by mitotic spindle. Here we show that condensin ATPase activity is an important regulator centromere stiffness function. Condensin depletion decreases 50% when applied to kinetochores. However, dispensable for normal level compaction (rest length) centromeres, which probably depends other factors control higher-order folding....
Abstract Exosomes are nanoscale vesicles that mediate intercellular communication. Cellular exosome uptake mechanisms not well defined partly due to the lack of specific inhibitors this complex cellular process. Exosome depends on cholesterol-rich membrane microdomains called lipid rafts and can be blocked by non-specific depletion plasma cholesterol. Scavenger receptor type B-1 (SR-B1), found in rafts, is a for high-density lipoproteins (HDL). We hypothesized synthetic nanoparticle mimic...
<title>Abstract</title> The complex dynamics of cytoskeletal meshworks make them a difficult subject study. With the advent fluorescent speckle microscopy (FSM) and other technological advances in techniques, much more is now known about how filamentous actin (F-actin) MT networks work within cells to give rise vast array functions which require them. A current challenge imaging field improve utility accuracy computational approaches required analyze large datasets. Here, we present results...
Several recent models for spindle length regulation propose an elastic pole to matrix that is sufficiently strong bear or antagonize forces generated by microtubules and microtubule motors. We tested this hypothesis using microneedles skewer metaphase spindles in Xenopus laevis egg extracts. Microneedle tips inserted into a just outside the plate resulted movement along interpolar axis at velocity slightly slower than poleward flux, bringing nearest toward needle. Spindle decreased near...
How nuclear size is regulated relative to cell a fundamental biological question. Reductions in both and sizes during
Abstract The development of a fertilized egg to an embryo requires the proper temporal control gene expression. During cell differentiation, timing is often controlled via cascades transcription factors (TFs). However, in early development, inactive, and many TF levels stay constant, suggesting that alternative mechanisms govern observed rapid ordered onset Here, we find embryonic access maternally deposited nuclear proteins genome temporally importin affinities, thereby expression...
Repellents evoke growth cone turning by eliciting asymmetric, localized loss of actin cytoskeleton together with changes in substratum attachment. We have demonstrated that semaphorin-3A (Sema3A)-induced detachment and collapse require eicosanoid-mediated activation protein kinase Cε (PKCε) the major PKCε target is myristoylated, alanine-rich C-kinase substrate (MARCKS). Here, we show PKC necessary for MARCKS, while at membrane, colocalizes α 3 -integrin a peripheral adhesive zone cone....
Detection of a repellent factor, such as semaphorin (Sema), causes localized collapse the growth cone and directs neurite away from repellent. Growth results concomitant cytoskeletal rearrangements detachment adhesion sites extracellular matrix, via mostly unknown signaling mechanisms. In cultures dorsal root ganglion neurons, we found that Sema3A treatment stimulates synthesis eicosanoid, 12(S)-hydroxyeicosatetraenoic acid (HETE), whereas Sema3A-induced is prevented when 12(S)-HETE blocked...
Distinct pathways from centrosomes and chromatin are thought to contribute in parallel microtubule nucleation stabilization during animal cell mitotic spindle assembly, but their full mechanisms not known. We investigated the function of three proposed nucleation/stabilization factors, TPX2, γ-tubulin XMAP215, chromatin-promoted assembly anastral spindles Xenopus laevis egg extract. In addition conventional depletion-add back experiments, we tested whether factors could substitute for each...
In many organisms, early embryonic development is characterized by a series of reductive cell divisions that result in rapid increases number and concomitant decreases size. Intracellular organelles, such as the nucleus mitotic spindle, also become progressively smaller during this developmental window, but molecular mechanistic underpinnings these scaling relationships are not fully understood. For changes cytoplasmic volume sufficient to account for size certain organisms. This observation...
In this work, we demonstrate that microtubule asters are able to center in a variety of cell geometries and can do so over long distances, even when the activity cytoplasmic dynein is inhibited. This observation, along with additional characterizations aster movements, consistent microtubule-based pushing mechanism.
Cell motility necessitates the rapid formation and disassembly of cell adhesions. We have studied adhesions in a highly motile melanoma line using various biochemical approaches microscopic techniques to image close report that WM-1617 cells contain at least two types adhesion: classic focal more extensive, irregularly shaped tend occur along lamellipodial edges. In contrast adhesions, these latter are dynamic can be disassembled rapidly via protein kinase C (PKC) activation (e.g. by...
The inherent experimental advantages of intact amphibian eggs have been exploited for several decades to advance our understanding fundamental developmental processes and the cell cycle. Characterization these at molecular level has greatly advanced by use cell-free extracts, which permit development biochemically tractable approaches. Demembranated Xenopus laevis sperm nuclei used with extracts recapitulate cycle progression control state egg extract. This system become an invaluable widely...
The in situ fabrication of poly(ethylene glycol) diacrylate (PEGDA) hydrogel microstructures within poly(dimethylsiloxane) (PDMS)-based microfluidic networks is a versatile technique that has enabled unique applications biosensing, medical diagnostics, and the fundamental life sciences. Hydrogel structures have previously been patterned by lithographic photopolymerization PEGDA forming solutions, process confounded oxygen-permeable PDMS. Here, we introduce an alternate PEG patterning relies...
1. ABSTRACT The complex dynamics of cytoskeletal meshworks make them a difficult subject study. With the advent fluorescent speckle microscopy (FSM) and other technological advances in techniques, much more is now known about how filamentous actin (F-actin) MT networks work within cells to give rise vast array functions which require them. A current challenge imaging field improve utility accuracy computational approaches required analyze large datasets. Here, we present results method that,...
During nervous system development axons reach their target areas under the influence of numerous guidance cues that affect rate and direction growth. This report addresses unsettled question whether to what extent growth velocity turning responses (attraction, repulsion) are interdependent. We exposed individual cones fetal rat dorsal root ganglion neurons in culture asymmetrically gradients seven different factors recorded rates angles. Growth exhibited divergent patterns responses. For...
Significance Eukaryotic (plant and animal) cells possess a nuclear membrane that separates the two stages of gene expression (transcription translation), whereas prokaryotic (bacteria archaea) lack barrier to colocated transcription translation. However, bacterium Gemmata obscuriglobus extensive intracellular membranes, resulting in superficially eukaryote-like cellular complexity. We have found substantial amount G. translation is uncoupled from transcription, broadening our understanding...