Tubulin microheterogeneity during mouse liver development

Liver tubulin was analyzed and characterized during the development of the mouse, from embryonic stages to adult. Separation and identification of isotubulins were achieved by isoelectric focusing, two-dimensional gel electrophoresis and peptide mapping. Liver tubulin is a heterogeneous population composed of 7 isoforms, 4 α and 3 β. By comparison with the events occurring at the tubulin level during brain development, we observed that 1) tubulin heterogeneity is less important in liver than in brain 2) no appearance of new isotubulins takes place during development 3) the only developmental change detectable in our gels is an accumulation of an α tubulin subunit which is absent from brain isotubulin population. The relationship between this α isotubulin accumulation and liver secretion during development is discussed.