BIOL3006 Lecture Notes - Lecture 3: Troponin, S Phase, Lac Operon
Document Summary
Myofibril = contracting unit: actin filaments and myosin motors. Each skeletal fibre is a long, single cell with multiple nuclei (myotube: these cells develop by the fusion of several myoblasts (precursor cell) Myoblasts proliferate extensively, but no longer divide once differentiated into myotubes. Myoblast differentiation is regulated by genes encoding muscle-specific proteins that are switched on co-ordinately. Muscle cells can be cultured in vitro and differentiation can be detected by using an ab against skeletal muscle (myosin) Differentiation proceeds through 3 distinct stages: proliferation of myoblasts, elongation of myocytes, fusion into myotubules. Myod famiy of tfs includes: myod5, myog, myf5, myf6. Myotubes (terminally (committed cells) (differentiating cells) differentiated cells) Myod expression is one of the earliest markers of myogenic commitment: however, muscle development is not dramatically inhibited in myod -/- knockout mice, suggests functional redundancy from other related factors, eg. Myf5 replaces myod when not present to continue differentiation between cell.
