Tubulin Isotypes and the Multigene Tubulin Families

Abstract

Publisher Summary This chapter describes tubulin gene structure, evolution, and expression. Microtubules are long filamentous structures that are found ubiquitously in eukaryotic cells and are intimately associated with many cellular functions. The major structural component of microtubules is tubulin, a dimer of α- and β-chains each of about 55,000 daltons. In spite of the remarkable diversity of microtubule functions, many independent lines of evidence point to a close evolutionary conservation among tubulin proteins. Indeed, hybrid microtubules may be formed in vitro by the copolymerization of α- and β-tubulins from different species. The evolutionary conservation of tubulin genes is dramatically shown at the nucleic acid level by the ability of cDNA probes constructed from chicken α- and β-tubulin mRNAs to cross-hybridize with genomic DNAs from a wide variety of eukaryotes under stringent conditions. Given that all cells express tubulin genes and that the proteins they encode are highly evolutionarily conserved, the extent of structural diversity among tubulin gene families from various species is rather remarkable.