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Sheng Wang

Publications and source records attributed to Sheng Wang.

79 records · Page 5Linked to original sources
PubMed2002

Prohibitin requires Brg-1 and Brm for the repression of E2F and cell growth.

E2F transcription factors play a major role in controlling mammalian cell cycle progression. We recently reported that a potential tumor suppressor, prohibitin, which interacts with retinoblastoma protein (Rb), regulates E2F function and this activity correlates with its growth-suppressive activity. We show here that prohibitin recruits Brg-1/Brm to E2F-responsive promoters, and that this recruitment is required for the repression of E2F-mediated transcription by prohibitin. Expression of a dominant-negative Brg-1 or Brm releases prohibitin-mediated repression of E2F and relieves prohibitin-mediated growth suppression. Although prohibitin associates with, and recruits, Brg-1 and Brm independently of Rb, prohibitin/Brg-1/Brm-mediated transcriptional repression requires Rb. A viral oncoprotein, SV40 large T antigen, can reverse prohibitin-mediated suppression of E2F-mediated gene transcription, and targets prohibitin through interruption of the association between prohibitin and Brg-1/Brm without affecting the prohibitin-E2F interaction.

Antigens, Polyomavirus Transforming↗
PubMed2002

Crystal structure of the Bacillus stearothermophilus anti-sigma factor SpoIIAB with the sporulation sigma factor sigmaF.

Cell type-specific transcription during Bacillus sporulation is established by sigmaF. SpoIIAB is an anti-sigma that binds and negatively regulates sigmaF, as well as a serine kinase that phosphorylates and inactivates the anti-anti-sigma SpoIIAA. The crystal structure of sigmaF bound to the SpoIIAB dimer in the low-affinity, ADP form has been determined at 2.9 A resolution. SpoIIAB adopts the GHKL superfamily fold of ATPases and histidine kinases. A domain of sigmaF contacts both SpoIIAB monomers, while 80% of the sigma factor is disordered. The interaction occludes an RNA polymerase binding surface of sigmaF, explaining the SpoIIAB anti-sigma activity. The structure also explains the specificity of SpoIIAB for its target sigma factors and, in combination with genetic and biochemical data, provides insight into the mechanism of SpoIIAA anti-anti-sigma activity.

Adenosine Triphosphate↗
PubMed2002

Effects of intracarotid injection of 17beta-estradiol on electrical activity of rostral ventrolateral medullary neurons in male rats.

The purpose of this study was to determine the effects of 17beta-estradiol (E(2)) on electrical activity of the rostral ventrolateral medulla (RVLM) neurons in rats. Male Sprague-Dawley rats were anesthetized with urethane (1.0 g/kg) and subjected to sino-aortic denervation. Blood pressure, heart rate and spontaneous discharge of RVLM neurons were recorded simultaneously. Intracarotid injection of E(2) (10 ng/kg) decreased the discharge rate from 14.46+/-0.47 to 9.73+/-0.33 spikes/s (P<0.001) in 25 out of 30 RVLM neurons, while blood pressure and heart rate showed no significant change. The inhibitory effect of E(2) on RVLM neuronal activity was rapid at the onset (within 1 min) and long-lasting (>5 min). Prior administration of antiestrogen tamoxifen (TAM) did not affect the effect of E(2). However, pretreatment with N( )-nitro-L-arginine-methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase, significantly attenuated the inhibitory effect of E(2). In addition, NO donor 3-morpholinosydnonimine (SIN-1) potentiated the effect of E(2). These results suggest that E(2) may inhibit spontaneous electrical activity of RVLM neurons, an effect which is mediated by the activation of NOS with the resultant of NO release via nongenomic actions.

Animals↗
PubMed2002

Nerve growth cone guidance mediated by G protein-coupled receptors.

Growing axons navigate by responding to chemical guidance cues. Here we report that growth cones of rat cerebellar axons in culture turned away from a gradient of SDF-1, a chemokine that attracts migrating leukocytes and cerebellar granule cells via a G protein-coupled receptor (GPCR). Similarly, Xenopus spinal growth cones turned away from a gradient of baclofen, an agonist of the GABA(B) receptor. This response was mediated by G(i) and subsequent activation of phospholipase C (PLC), which triggered two pathways: protein kinase C (PKC) led to repulsion, and inositol 1,4,5-triphosphate (IP(3)) receptor activation led to attractive turning. Under normal culture conditions, PKC-dependent repulsion dominated, but the repulsion could be converted to attraction by inhibiting PKC or by elevating cytosolic cGMP. Thus, GPCRs can mediate both repulsive and attractive axon guidance in vitro, and chemokines may serve as guidance cues for axon pathfinding.

Aminocaproic Acid↗
PubMed2002

[A monitoring study of electromyography median frequency on fatigue of erector spinalis in drivers working at high altitude].

OBJECTIVE: To evaluate the role of muscle fatigue in the pathogenesis of high prevalence of low back pain(LBP) in drivers who work at high altitude, in order to seek the effective measures for prevention and treatment of LBP. METHOD: The spectral electromyographic(EMG) changes during isometric contraction of erector spinalis to fatigue in 26 drivers in the field were consecutively recorded after daily driving for 5 days. The relationship between the decline of median frequency and the development of the back extensor fatigue were analyzed. RESULTS: The decline rates of EMG median frequency of the erector spinalis on 1-5 working day [(-0.258 +/- 0.087), (-0.248 +/- 0.070), (-0.256 +/- 0.097), (-0.267 +/- 0.093), (-0.274 +/- 0.081)%/s respectively] were significantly different from that of baseline measured before work [(-0.175 +/- 0.114)%/s, P < 0.05 or P < 0.01]. A positive correlation was also found between the decline rate and the working time(r = -0.809, P < 0.05). CONCLUSION: The high prevalence of LBP in the drivers working at high altitude is due to acumulative fatigue of back extensor resulting from long-distance driving, lack of proper rest, decrease of muscle endurance and increase of liability to fatigue, consequently leading to the muscle dysfunction and finally LBP.

Altitude↗
PubMed2002

[Lower back pain in truck drivers working in plateau areas and its prevention].

OBJECTIVE: To investigate the epidemiological characteristics of lower back pain of truck drivers in plateau areas with an analysis of the causes and evaluated the effects of the protective measures. METHODS: The self-reported lower back symptom was investigated by questionnaire in 1,132 male drivers in plateau areas. Vibration of the driver lumbar back was measured real time with or without wearing corset. Study the effect of the special corset for drivers and the massage on back by self-control design of big sample intervention experiments. RESULTS: The prevalence of lower back pain of drivers in plateau areas was 86.1%. High level of its prevalence is due to many factors. Special corset for drivers and massage on back by themselves can reduce the degree of the pain. CONCLUSION: Driving in plateau areas is a special occupational work with high level of prevalence of lower back pain which can be prevented.

Automobile Driving↗