박혜윤 교수

The transcription and transport of messenger RNA (mRNA) are critical steps in regulating the spatial and temporal components of gene expression, but it has not been possible to observe the dynamics of endogenous mRNA in primary mammalian tissues. We have developed a transgenic mouse in which all β-actin mRNA is fluorescently labeled. We found that β-actin mRNA in primary fibroblasts localizes predominantly by diffusion and trapping as single mRNAs. In cultured neurons and acute brain slices, we

We describe a microfluidic mixer that is well-suited for kinetic studies of macromolecular conformational change under a broad range of experimental conditions. The mixer exploits hydrodynamic focusing to create a thin jet containing the macromolecules of interest. Kinetic reactions are triggered by molecular diffusion into the jet from adjacent flow layers. The ultimate time resolution of these devices can be restricted by premature contact between co-flowing solutions during the focusing proce

A microfluidic mixer is applied to study the kinetics of calmodulin conformational changes upon Ca2+ binding. The device facilitates rapid, uniform mixing by decoupling hydrodynamic focusing from diffusive mixing and accesses time scales of tens of microseconds. The mixer is used in conjunction with multiphoton microscopy to examine the fast Ca2+-induced transitions of acrylodan-labeled calmodulin. We find that the kinetic rates of the conformational changes in two homologous globular domains di

Localized translation plays a crucial role in synaptic plasticity and memory consolidation. However, it has not been possible to follow the dynamics of memory-associated mRNAs in living neurons in response to neuronal activity in real time. We have generated a novel mouse model where the endogenous Arc/Arg3.1 gene is tagged in its 3' untranslated region with stem-loops that bind a bacteriophage PP7 coat protein (PCP), allowing visualization of individual mRNAs in real time. The physiological res

Localization of mRNA is a critical mechanism used by a large fraction of transcripts to restrict its translation to specific cellular regions. Although current high-resolution imaging techniques provide ample information, the analysis methods for localization have either been qualitative or employed quantification in nonrandomly selected regions of interest. Here, we describe an analytical method for objective quantification of mRNA localization using a combination of two characteristics of its

As the coronavirus disease 2019 (COVID-19) has rapidly spread worldwide, there are growing concerns about patients' mental health. We investigated psychological problems in COVID-19 patients assessed with self-reported questionnaires including the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7 scale, and Impact of Event Scale- Revised Korean version. Ten patients who recovered from COVID-19 pneumonia without complications underwent self-reported questionnaires about 1 month after

As basic units of neural networks, ensembles of synapses underlie cognitive functions such as learning and memory. These synaptic engrams show elevated synaptic density among engram cells following contextual fear memory formation. Subsequent analysis of the CA3-CA1 engram synapse revealed larger spine sizes, as the synaptic connectivity correlated with the memory strength. Here, we elucidate the synapse dynamics between CA3 and CA1 by tracking identical synapses at multiple time points by adapt

Thyroid hormone (T3) receptors (T3Rs) regulate transcription by binding to T3 response elements (TREs) located within promoter regions of T3-regulated genes. In rat pituitary GH4C1 cells, expression of a reporter containing herpes simplex virus thymidine kinase (TK) gene sequences (-105/+51) linked to the chloramphenicol acetyltransferase gene was stimulated 4- to 5-fold by T3. Linker scanning mutants of the TK promoter revealed that regions around -80 containing a CTF/NF-1 recognition sequence

Local protein synthesis mediates precise spatio-temporal regulation of gene expression for neuronal functions such as long-term plasticity, axon guidance and regeneration. To reveal the underlying mechanisms of local translation, it is crucial to understand mRNA transport, localization and translation in live neurons. Among various techniques for mRNA analysis, fluorescence microscopy has been widely used as the most direct method to study localization of mRNA. Live-cell imaging of single RNA mo

From biogenesis to degradation, mRNA goes through diverse types of regulation and interaction with other biomolecules. Uneven distribution of mRNA transcripts and the diverse isoforms and modifications of mRNA make us wonder how cells manage the complexity and keep the functional integrity for the normal development of cells and organisms. Single-molecule microscopy tools have expanded the scope of RNA research with unprecedented spatiotemporal resolution. In this review, we highlight the recent

Coronavirus disease-19 (COVID-19) caused by a new emerging virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), led to a major public health crisis worldwide, including Korea in 2020. Infected people may experience a wide spectrum of COVID-19-related physical and mental symptoms and psychosocial difficulties, including abrupt isolation, being blamed by others, death of a loved one by COVID-19, and financial loss. Although the data is limited so far, a recently growing number of s

A hallmark of α-synucleinopathies (e.g., Parkinson's disease) is the misfolding and aggregation of α-synuclein in tissues and biological fluids. Protein amplification assays like real-time quaking-induced conversion (RT-QuIC) are sensitive yet currently limited to semi-invasive sample types such as cerebrospinal fluid because more accessible samples, such as blood, contain inhibitors. Here, we show that Nanoparticle-enhanced Quaking-induced Conversion (Nano-QuIC) can double the speed of reaction