• BMB Reports
• /
• v.51 no.4
• /
• pp.163-164
• /
• 2018

CONSTANS (CO) induces the expression of FLOWERING LOCUS T (FT) in the photoperiodic pathway, and thereby regulates the seasonal timing of flowering. CO expression is induced and CO protein is stabilized by FLAVIN-BINDING KELCH REPEAT F-BOX PROTEIN 1 (FKF1) in the late afternoon, while CO is degraded by CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) during the night. These regulatory cascades were thought to act independently. In our study, we investigated the relationship between FKF1 and COP1 in the regulation of CO stability in response to ambient light conditions. A genetic analysis revealed that FKF1 acts as a direct upstream negative regulator of COP1, in which cop1 mutation is epistatic to fkf1 mutation in the photoperiodic regulation of flowering. COP1 activity requires the formation of a hetero-tetramer with SUPPRESSOR OF PHYA-105 (SPA1), [$(COP1)_2(SPA1)_2$]. Light-activated FKF1 has an increased binding capacity for COP1, forming a FKF1-COP1 hetero-dimer, and inhibiting COP1 homo-dimerization at its coiled-coil (CC) domain. Mutations in the CC domain result in poor COP1 dimerization and misregulation of photoperiodic floral induction. We propose that FKF1 represses COP1 activity by inhibiting COP1 dimerization in the late afternoon under long-day conditions, resulting in early flowering.

• Journal of Life Science
• /
• v.30 no.1
• /
• pp.10-17
• /
• 2020

Kinesin-1 is microtubule-dependent plus-end direct molecular motor protein essential for intracellular transport. It is a member of the kinesin superfamily proteins (KIFs) which transport cargo, including organelles, vesicles, neurotransmitter receptors, cell-signaling molecules, and protein complexes through interaction between its light chain subunit and the cargo. Kinesin light chain 1 (KLC1) is a non-motor subunit that associates with the kinesin heavy chain (KHC). Although KLC1 interacts with many different adaptor proteins and scaffolding proteins, its binding proteins have not yet been fully identified. We used the yeast two-hybrid assay to identify proteins that interact with the tetratricopeptide repeat (TPR) domain of KLC1, and found an interaction between KLC1 and EH domain-binding protein 1 like 1 (EHBP1L1). EHBP1L1 bound to the region containing all six TPR repeats of KLC1 and did not interact with KIF5B (a motor protein of kinesin 1) or KIF3A (a motor protein of kinesin 2) in the yeast two-hybrid assay. The carboxyl-terminus of the coiled-coil domain of EHBP1L1 is essential for interaction with KLC1. However, another EHBP1L1 isoform, EHBP1, did not interact with KLC1 in the yeast two-hybrid assay. KLC1 interacted with GST-EHBP1L1 and its coiled-coil domain but not with GST only. When co-expressed in HEK-293T cells, EHBP1L1 co-localized with KLC1 and co-immunoprecipitated with KLC1 and KIF5B but not KIF3A. These results suggest that kinesin 1 motor protein may transport EHBP1L1-associated cargo in cells.

• Journal of Magnetics
• /
• v.21 no.3
• /
• pp.330-339
• /
• 2016

A magnetic field sensing system with a single primary sensor and multiple reference sensors deployed locally and orthogonally, was proposed for downlink signal reception and interference cancelling for Through-the-Earth Communication (TEC). This paper mathematically analyzes a design optimization process for a search coil magnetometer (SCM), and applies that process to minimize the bandwidth of the primary SCM for TEC signal reception and the volume of reference SCMs for multiple distributions. The primary SCM achieves a 3-dB bandwidth of 7 Hz, a sensitivity threshold of 120 fT/${\surd}$Hz, and a volume of $2.32{\times}10^{-4}m^3$. The entire sensing system volume is as small as $10^{-2}m^3$. Experiments with interference from industrial frequency harmonics demonstrated an average of 36 dB and 18 dB improvements in signal-to-interference ratio and signal-to-interference plus noise ratio, respectively, using multichannel recursive-least-squares algorithm. Thus, the proposed sensing system can reduce the interference effectively and allows reliable downlink signal reception.

• Korean Journal of Biological Psychiatry
• /
• v.12 no.1
• /
• pp.68-72
• /
• 2005

Object:Nicotine dependence is the most common substance abuse disorder. One of the characteristics of nicotine dependence is craving. Regional activation of the brain induced by craving for nicotine was evaluated by using functional magnetic resonance imaging to investigate neuroanatomical site of smoking craving. Method:A smoker who satisfied DSM-IV criteria for nicotine dependence and a non smoker was studied. MRI data were acquired on a 1.5T Magnetom Vision Plus with a head volume coil. Two sets of visual stimuli were presented to subjects in a random manner. One was the film scenes of inducing smoking craving and the other was neutral stimuli not related to smoking. There were two fMRI sessions before and after smoking or sham smoking. Data were analyzed using SPM99. Results:fMRI showed significant activated area in anterior cingulate and medial frontal lobes in the smoker during smoking craving. Right dorsolateral prefrontal cortex and parietal lobes were activated in the control during visual stimulation before smoking. After smoking, there was no brain activation during visual stimulation in both of smoker and non smoker. Conclusion:Metabolic activity of the anterior cingulate and medial frontal lobes increased during craving for smoking. This result suggests that fMRI may be a valuable tool in the identification of neurobiological process of craving.

• Journal of Korean Neurosurgical Society
• /
• v.38 no.4
• /
• pp.269-272
• /
• 2005

Objective : The object of this study is to present the treatment experience of the 6cases of scalp arteriovenous malformations[AVMs] focus on treatment strategy. Methods : Six patients with scalp AVM were treated during past 12years. We analysis the clinical characteristics of the lesions, treatment methods and management outcomes. Results : The lesions were located on temporal in 2patients, parietal in 2patients, frontal and occipital area in each one. Four of six patients had a trauma history on scalp. The presenting symptoms were progressive enlarged pulsating mass with or without bruit. Four of the six lesions had the large fistula in the lesion. Two patients were treated with surgical resection alone, three patients with proximal feeding artery balloon[s] occlusion followed by surgical resection, and one patient with coil embolization through trans-venous route alone. We obtained good results in all patients. Conclusion : Most of scalp AVM can be completely cured by Judicious selection and a combination of treatment modalities, i.e., surgery only, or embolization only, or embolization plus surgical therapy. Although embolization became a primary therapy for this sort of scalp AVM recently, the selection of treatment modality should be chose based on the size, angioarchitecture, and clinical presentations of the lesion.

• Investigative Magnetic Resonance Imaging
• /
• v.8 no.2
• /
• pp.79-85
• /
• 2004

Purpose : To evaluate the usefulness and reproducibility of $^1H$ MRS in different 1.5 T MR machines with different coils to compare the SNR, scan time and the spectral patterns in different brain regions in normal volunteers. Materials and Methods : Localized $^1H$ MR spectroscopy ($^1H$ MRS) was performed in a total of 10 normal volunteers (age; 20-45 years) with spectral parameters adjusted by the autoprescan routine (PROBE package). In all volunteers, MRS was performed in a three times using conventional MRS (Signa Horizon) with 1 channel coil and upgraded MRS (Echospeed plus with EXCITE) with both 1 channel and 8 channel coil. Using these three different machines and coils, SNRs of the spectra in both phantom and volunteers and (pre)scan time of MRS were compared. Two regions of the human brain (basal ganglia and deep white matter) were examined and relative metabolite ratios (NAA/Cr, Cho/Cr, and mI/Cr ratios) were measured in all volunteers. For all spectra, a STEAM localization sequence with three-pulse CHESS $H_2O$ suppression was used, with the following acquisition parameters: TR=3.0/2.0 sec, TE=30 msec, TM=13.7 msec, SW=2500 Hz, SI=2048 pts, AVG : 64/128, and NEX=2/8 (Signa/Echospeed). Results : The SNR was about over $30\%$ higher in Echospeed machine and time for prescan and scan was almost same in different machines and coils. Reliable spectra were obtained on both MRS systems and there were no significant differences in spectral patterns and relative metabolite ratios in two brain regions (p>0.05). Conclusion : Both conventional and new MRI systems are highly reliable and reproducible for $^1H$ MR spectroscopic examinations in human brains and there are no significant differences in applications for $^1H$ MRS between two different MRI systems.

• Journal of Korean Neurosurgical Society
• /
• v.44 no.4
• /
• pp.228-233
• /
• 2008

Objective : The standard treatment strategy of intracranial aneurysms includes either endovascular coiling or microsurgical clipping. In certain situations such as in giant or dissecting aneurysms, bypass surgery followed by proximal occlusion or trapping of parent artery is required. Methods : The authors assessed the result of extracranial-intracranial (EC-IC) bypass surgery in the treatment of complex intracranial aneurysms in one institute between 2003 and 2007 retrospectively to propose its role as treatment modality. The outcomes of 15 patients with complex aneurysms treated during the last 5 years were reviewed. Six male and 9 female patients, aged 14 to 76 years, presented with symptoms related to hemorrhage in 6 cases, transient ischemic attack (TIA) in 2 un ruptured cases, and permanent infarction in one, and compressive symptoms in 3 cases. Aneurysms were mainly in the internal carotid artery (ICA) in 11 cases, middle cerebral artery (MCA) in 2, posterior cerebral artery (PCA) in one and posterior inferior cerebellar artery (PICA) in one case. Results : The types of aneurysms were 8 cases of large to giant size aneurysms, 5 cases of ICA blood blister-like aneurysms, one dissecting aneurysm, and one pseudoaneurysm related to trauma. High-flow bypass surgery was done in 6 cases with radial artery graft (RAG) in five and saphenous vein graft (SVG) in one. Low-flow bypass was done in nine cases using superficial temporal artery (STA) in eight and occipital artery (OA) in one case. Parent artery occlusion was performed with clipping in 9 patients, with coiling in 4, and with balloon plus coil in 1. Direct aneurysm clip was done in one case. The follow up period ranged from 2 to 48 months (mean 15.0 months). There was no mortality case. The long-term clinical outcome measured by Glasgow outcome scale (GOS) showed good or excellent outcome in 13/15. The overall surgery related morbidity was 20% (3/15) including 2 emergency bypass surgeries due to unexpected parent artery occlusion during direct clipping procedure. The short-term postoperative bypass graft patency rates were 100% but the long-term bypass patency rates were 86.7% (13/15). Nonetheless, there was no bypass surgery related morbidity due to occlusion of the graft. Conclusion : Revascularization technique is a pivotal armament in managing complex aneurysms and scrupulous prior planning is essential to successful outcomes.