Differential expression of thymosins beta(4) and beta(10) during rat cerebellum postnatal development

The beta -thymosins are a family of actin monomer-sequestering proteins wid ely distributed among vertebrate classes. The most abundant beta -thymosins in mammalian species are thymosin beta (4), (T beta,) and thymosin beta (1 0) (T beta (10)), two small peptides (43 amino acids) sharing a high degree of sequence homology. In the present work, we have analyzed the distributi on of T beta (4) and T beta (10) in the developing and adult rat cerebellum using in situ hybridization and immunohistochemistry techniques. Our resul ts show that the temporal and cellular patterns of expression of both beta -thymosins are different. In the young (7 and 18 postnatal days) and adult (1 and 4 months old) rat cerebellum, T beta (4) was mainly expressed in the glia (microglia, Golgi epithelial cells and oligodendrocytes), neurons (gr anule cells and Purkinje cells), and in the capillaries. In 14-month-old ra ts, the T beta (4) immunoreactivity was only detected in some microglia cel ls. In young and adult animals, most of the T beta (4) immunoreactivity was localized in several types of neuronal cells including granule cells, Golg i neurons and Purkinje cells. In old animals, a faint T beta (10) signal co uld be detected in a few Purkinje cells. Our results suggest that each beta -thymosin could play a different function in the control of actin dynamics . (C) 2001 Elsevier Science B.V. All rights reserved.