STATHMIN EXPRESSION IS A FEATURE OF PROLIFERATING CELLS OF MOST, IF NOT ALL, CELL LINEAGES

BACKGROUND: Stathmin is a phylogenetically conserved protein which was identified initially as a prominent cytosolic protein in hemopoietic cells, endocrine cells, brain, and testis. In these tissues, it has be en suggested that the level of stathmin expression is important in dev elopment and cell proliferation. Furthermore, stathmin phosphorylation appears to be involved in the regulation of cell growth arrest, termi nal differentiation, and hormone secretion. Elevated levels of express ion of stathmin have been described in leukemia and lymphoma cells. Th e aim of this study was to characterize the distribution of cells that express the stathmin protein in a wide variety of normal human and ro dent tissues. EXPERIMENTAL DESIGN: First, antisera against a synthetic stathmin peptide have been raised in rabbits and the specificity of t hese antisera confirmed by their reactivity with stathmin on 1-dimensi onal and 2-dimensional Western blots. Second, the most appropriate mea ns of fixing tissues in order to stain stathmin has been investigated. Finally, using the optimized conditions of tissue fixation, the antis era have been used to immunostain sections taken from a wide variety o f tissues. RESULTS: Immunopositivity was found in cells of all the lin eages studied, with the stained cells present within the proliferating compartment of tissues. Conversely, most nonproliferating mature cell s did not stain with the antisera to stathmin. The only nonproliferati ng cells that appeared to express stathmin were a subpopulation of gli al cells, neurons, and anterior pituitary cells. CONCLUSIONS: It is pr oposed that stathmin is necessary for cell proliferation in most, or a ll, cell lineages and that its primary function relates to some aspect of cell division.