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Guangyu Wang

Publications and source records attributed to Guangyu Wang.

8 recordsLinked to original sources
PubMed2025

Somatic and germinal mosaicism of a canonical splicing variant causing limb-girdle muscular dystrophy type 1B.

Limb-girdle muscular dystrophy type 1B is one of several muscular dystrophies caused by pathogenic variants in the LMNA gene. In this study, we investigated the clinical, pathological, and genetic findings of an LGMD1B family. Genetic sequencing identified the proband and her younger brother both carried the canonical splicing c.513 + 1G > A variant in the LMNA gene. The variant was absent in the proband's mother, and a certain percentage of the LMNA variant was identified in the venous blood, urine, and semen sample of the proband's father by pyrophosphate sequencing. Further cDNA analysis demonstrated that the canonical splicing c.513 + 1G > A variant in intron 2 induced retention of the first 45 bp of intron 2, resulting in an in-frame insertion of 15 amino acids. Our study directly confirmed the presence of somatic and germinal mosaicism in the LGMD1B family and the pathogenicity of the canonical splicing variant in the LMNA gene.

Humans↗
PubMed2006

Voltage-dependent gating rearrangements in the intracellular T1-T1 interface of a K+ channel.

The intracellular tetramerization domain (T1) of most eukaryotic voltage-gated potassium channels (Kv channels) exists as a "hanging gondola" below the transmembrane regions that directly control activation gating via the electromechanical coupling between the S4 voltage sensor and the main S6 gate. However, much less is known about the putative contribution of the T1 domain to Kv channel gating. This possibility is mechanistically intriguing because the T1-S1 linker connects the T1 domain to the voltage-sensing domain. Previously, we demonstrated that thiol-specific reagents inhibit Kv4.1 channels by reacting in a state-dependent manner with native Zn(2+) site thiolate groups in the T1-T1 interface; therefore, we concluded that the T1-T1 interface is functionally active and not protected by Zn(2+) (Wang, G., M. Shahidullah, C.A. Rocha, C. Strang, P.J. Pfaffinger, and M. Covarrubias. 2005. J. Gen. Physiol. 126:55-69). Here, we co-expressed Kv4.1 channels and auxiliary subunits (KChIP-1 and DPPX-S) to investigate the state and voltage dependence of the accessibility of MTSET to the three interfacial cysteines in the T1 domain. The results showed that the average MTSET modification rate constant (k(MTSET)) is dramatically enhanced in the activated state relative to the resting and inactivated states (approximately 260- and approximately 47-fold, respectively). Crucially, under three separate conditions that produce distinct activation profiles, k(MTSET) is steeply voltage dependent in a manner that is precisely correlated with the peak conductance-voltage relations. These observations strongly suggest that Kv4 channel gating is tightly coupled to voltage-dependent accessibility changes of native T1 cysteines in the intersubunit Zn(2+) site. Furthermore, cross-linking of cysteine pairs across the T1-T1 interface induced substantial inhibition of the channel, which supports the functionally dynamic role of T1 in channel gating. Therefore, we conclude that the complex voltage-dependent gating rearrangements of eukaryotic Kv channels are not limited to the membrane-spanning core but must include the intracellular T1-T1 interface. Oxidative stress in excitable tissues may perturb this interface to modulate Kv4 channel function.

Animals↗
PubMed2006

[Study on the pyrolysis behavior of geranyl-beta-D-glucopyranoside by gas chromatography-mass spectrometry].

In order to investigate the pyrolysis behavior of the flavor precursor of geranyl-beta-D-glucopyranoside, the glycoside was pyrolyzed at 200, 300, 400 degrees C in an on-line pyrolyzer under anaerobic conditions and in an off-line mode separately. Gas chromatography-mass spectrometry (GC/MS) was used for the qualitative and quantitative analysis of the pyrolysis products. the results. Little geranyl-beta-D-glucopyranoside was pyrolyzed at 200 degrees C and there were a large amount of geraniol and little by-products produced at 300 degrees C. With the increasing temperature to 400 degrees C, both the pyrolytic products and by-products were significantly increased. Therefore, it indicated that the optimized temperature of pyrolysis was 300 degrees C. The main pyrolysis product of the glycoside was geraniol. It showed the primary decomposition reaction took place with the breaking of glycosidic linkage, the cleavage of O-glycosidic bond as expected. The on-line mode experiment was a rapid and good qualitative method for the pyrolysis, and the off-line mode can be used as a quantitative method based on the qualitative analysis.

Acyclic Monoterpenes↗
PubMed2005

Functionally active t1-t1 interfaces revealed by the accessibility of intracellular thiolate groups in kv4 channels.

Gating of voltage-dependent K(+) channels involves movements of membrane-spanning regions that control the opening of the pore. Much less is known, however, about the contributions of large intracellular channel domains to the conformational changes that underlie gating. Here, we investigated the functional role of intracellular regions in Kv4 channels by probing relevant cysteines with thiol-specific reagents. We find that reagent application to the intracellular side of inside-out patches results in time-dependent irreversible inhibition of Kv4.1 and Kv4.3 currents. In the absence or presence of Kv4-specific auxiliary subunits, mutational and electrophysiological analyses showed that none of the 14 intracellular cysteines is essential for channel gating. C110, C131, and C132 in the intersubunit interface of the tetramerization domain (T1) are targets responsible for the irreversible inhibition by a methanethiosulfonate derivative (MTSET). This result is surprising because structural studies of Kv4-T1 crystals predicted protection of the targeted thiolate groups by constitutive high-affinity Zn(2+) coordination. Also, added Zn(2+) or a potent Zn(2+) chelator (TPEN) does not significantly modulate the accessibility of MTSET to C110, C131, or C132; and furthermore, when the three critical cysteines remained as possible targets, the MTSET modification rate of the activated state is approximately 200-fold faster than that of the resting state. Biochemical experiments confirmed the chemical modification of the intact alpha-subunit and the purified tetrameric T1 domain by MTS reagents. These results conclusively demonstrate that the T1--T1 interface of Kv4 channels is functionally active and dynamic, and that critical reactive thiolate groups in this interface may not be protected by Zn(2+) binding.

Animals↗
PubMed2004

Detection of point mutation and insertion mutations in DNA using a quartz crystal microbalance and MutS, a mismatch binding protein.

MutS protein is a mismatch binding protein that recognizes mispaired and unpaired base(s) in DNA. In this study, we incorporate the MutS protein-based mutation recognition into quartz crystal microbalance (QCM) measurements for DNA single-base substitution mutation and 1-4 base(s) insertion (or deletion) mutation detection. The method involves the immobilization of single-stranded probe DNA on a QCM surface, the hybridization of target DNA to form homoduplex or heteroduplex DNA, and finally the application of MutS protein for the mutation recognition. By measuring the MutS binding signal, DNA containing a T:G mismatch or unpaired base(s) is(are) discriminated against perfectly matched DNA at target concentrations ranging from 1nM to 5 microM. Furthermore, the QCM damping behavior upon MutS-DNA complex formation is studied using a Network Analyzer. The measured motional resistance changes per coupled MutS unit mass (deltaR/deltaf) are found to be indicative of the viscoelastic or structural properties of the bound protein, corresponding to different binding mechanisms. In addition, the deltaR/deltaf values vary remarkably when the MutS protein binds at different distances away from the QCM surface. Thus, these values can be used as a "fingerprint" for MutS mismatch recognition and also used to quantitatively locate the mutation site.

Adenosine Triphosphatases↗