Plant tubulin genes : regulatory and evolutionary aspects

Once transcribed at its own DNA locus, a tubulin monomer knows that it will be eventually incorporated within microtubules (MTs). What it does not know, though, is how it will ultimately reach its final destination, how complex the path will be, and at which regulatory step it will have to stop. In fact, this will depend upon the status of the cell, the genetic background and the external stimuli. In this article, we will try to guide the reader through the many places of this fascinating journey. In the post-genomic era it may appear anachronistic to keep studying plant tubulin genes. We all know what they do: they encode tubulin, one of the major cytoskeletal proteins, the building block of microtubules (MTs). However, accumulation of the transcripts of the various tubulin genes of plants, tubulin synthesis and post-translational modification, tubulin folding and assembly into MTs, and control of MT dynamics and positioning remain as fascinating, vast and still unresolved fields of investigation, full of novelties and peculiarities. We may as well call this arena of research microTUBULOMICS, recognizing the very many aspects that impinge on tubulin expression and subunit turn-over, accumulation, and interaction with proteins and drugs.