The C-terminal domain of glyceraldehyde 3-phosphate dehydrogenase plays an important role in suppression of tRNALys3 packaging into human immunodeficiency virus type-1 particles

AbstractHuman immunodeficiency virus type-1 (HIV-1) requires the packaging of human tRNALys3 as a primer for effective viral reverse transcription. Previously, we reported that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) suppresses the packaging efficiency of tRNALys3. Although the binding of GAPDH to Pr55gag is important for the suppression mechanism, it remains unclear which domain of GAPDH is responsible for the interaction with Pr55gag. In this study, we show that Asp256, Lys260, Lys263 and Glu267 of GAPDH are important for the suppression of tRNALys3 packaging. Yeast two-hybrid analysis demonstrated that the C-terminal domain of GAPDH (151–335) interacts with both the matrix region (MA; 1–132) and capsid N-terminal domain (CA-NTD; 133–282). The D256R, K263E or E267R mutation of GAPDH led to the loss of the ability to bind to wild-type (WT) MA, and the D256R/K260E double mutation of GAPDH resulted in the loss of detectable binding activity to WT CA-NTD. In contrast, R58E, Q59A or Q63A of MA, and E76R or R82E of CA-NTD abrogated the interaction with the C-terminal domain of GAPDH. Multiple-substituted GAPDH mutant (D256R/K260E/K263E/E267R) retained the oligomeric formation with WT GAPDH in HIV-1 producing cells, but the incorporation level of the hetero-oligomer was decreased in viral particles. Furthermore, the viruses produced from cells expressing the D256R/K260E/K263E/E267R mutant restored tRNALys3 packaging efficiency because the mutant exerted a dominant negative effect by preventing WT GAPDH from binding to MA and CA-NTD and improved the reverse transcription. These findings indicate that the amino acids Asp256, Lys260, Lys263 and Glu267 of GAPDH is essential for the mechanism of tRNALys3-packaging suppression and the D256R/K260E/K263E/E267R mutant of GAPDH acts in a dominant negative manner to suppress tRNALys3 packaging

Median alveolar cleft and palatal mass without a median upper cleft lip

Median cleft is rare among facial clefts, including bilateral and unilateral clefts. Median upper cleft lip and median alveolar cleft correspond to Type 14 and Type 0, respectively, in Tessier's classification system. Some authors have reported surgical procedures for median cleft. In the case of median alveolar cleft, bone grafting to the cleft side and orthodontics are generally applied, similarly to bilateral or unilateral cleft. Median alveolar cleft is usually accompanied by median upper cleft lip, the degree of which differs in each case. The symptoms include, but are not limited to, median lip defect, wide philtrum, and vermilion notch. However, an isolated alveolar cleft is extremely rare. We encountered a patient with an isolated alveolar cleft who did not have a light median upper cleft lip, such as a wide philtrum or vermilion notch. We herein report this case and describe its treatment

Efficacy of the New Double-Layer Stent for Unresectable Distal Malignant Biliary Obstruction: A Single-Center Retrospective Study

Background and Aims. For distal malignant biliary obstruction in cases with short life expectancy, occlusion of plastic stents (PSs) does not usually occur before death, and the application of such a procedure is considered adequate from the viewpoint of cost-effectiveness. Methods and Setting. A new commercially available DLS with side holes, a conventional DLS, and, uncovered self-expanding metal stents (SEMSs) were retrospectively evaluated in patients with jaundice due to unresectable distal malignant biliary obstruction. Results. A total of 64 patients received endoscopic biliary stenting (23 patients with the new DLS, 24 patients with conventional DLS, and 17 patients with uncovered SEMS) from December 2002 to August 2009. Median patency time was found to be 198 days for the new DLS group and 99 days for the conventional DLS group, revealing a significant difference between devices. There was, however, no significant difference in median patency time between the new DLS and the uncovered SEMS (198 days versus 344 days). Conclusion. The new DLS is efficient and safe and may be considered the first choice for unresectable distal malignant obstruction in cases with short life expectancy

Interfacial Element for Finite Element Modal Analysis of Bolted Joints

Multi-material structures are going to be a main scheme to construct automobiles. For the construction of multi-material structures, techniques to join dissimilar materials are required. The major joining techniques are classified into welding, adhesion and mechanical fastening such as bolted joints and riveting. Especially, bolted joints enable joining of metallic materials (steel and aluminium alloy, etc.) and non-metallic materials (CFRP, etc.) with high joint strength. However, the total stiffness of structures with bolted joints is relatively low because interfaces in bolted joints just contact each other, and its interfacial stiffness is lower than elastic modulus of base materials. Moreover, interfacial stiffness of bolted joints depends on clamping force of bolt and nut. This study has proposed an interfacial element for finite element modal analysis of bolted joints. The interfacial element simulates interfacial stiffness of bolted joints. Contact of interfaces is assumed to be the Hertzian contact of elastic asperities whose peak heights obey the Gaussian distribution. Based on this assumption, the stiffness of the interfacial element is derived from the compressive stress and the surface texture of the interfaces. By using the finite element model with the interfacial element, the modal analysis computes the natural frequency and the vibration mode. Finite element simulations and hammering tests have been conducted with several bolted joints. In general, the natural frequency of the bolted joints in the hammering tests increases with the increase in the clamping force, but it is lower than the calculation results in which the stiffness reduction of the jointed interfaces is ignored. The calculation results by using the proposed interfacial element agree with the hammering tests. Therefore, the proposed interfacial element contributes to improvement of modal analysis of bolted joints by mathematically modelling stiffness reduction of jointed interfaces based on tribology