Histone H3.3 sub-variant H3mm7 is required for normal skeletal muscle regeneration

Regulation of gene expression requires selective incorporation of histone H3 variant H3.3 into chromatin. Histone H3.3 has several subsidiary variants but their functions are unclear. Here we characterize the function of histone H3.3 sub-variant, H3mm7, which is expressed in skeletal muscle satellite cells. H3mm7 knockout mice demonstrate an essential role of H3mm7 in skeletal muscle regeneration. Chromatin analysis reveals that H3mm7 facilitates transcription by forming an open chromatin structure around promoter regions including those of myogenic genes. The crystal structure of the nucleosome containing H3mm7 reveals that, unlike the S57 residue of other H3 proteins, the H3mm7-specific A57 residue cannot form a hydrogen bond with the R40 residue of the cognate H4 molecule. Consequently, the H3mm7 nucleosome is unstable in vitro and exhibited higher mobility in vivo compared with the H3.3 nucleosome. We conclude that the unstable H3mm7 nucleosome may be required for proper skeletal muscle differentiation

Creep modelling of microstructurally unstable martensitic steels

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Isothermal, Thermo-Mechanical and Bithermal Fatigue Life of Ni Base Alloy HR6W for Piping in 700°C USC Power Plants

AbstractThree types of high temperature fatigue tests are carried out for HR6W, which is one of the candidate materials for piping in an advanced ultra super critical (A-USC) power boiler operating over 700°C steam condition. The first test is the isothermal fatigue test at 700°C, the second one is the thermo-mechanical fatigue (TMF) test between 100°Cand 700°C under in-phase and out-of-phase conditions, the final one is the bithermal fatigue (BTF) test at 100°C and 700°C. The relations between the partitioned inelastic strain range determined by the strain range partitioning method and the life in those tests show good agreement, while the relations between the total strain range and the life show some differences