MOLECULAR-CLONING AND EXPRESSION STUDIES OF 2 DIVERGENT ALPHA-TUBULINGENES IN NEUROSPORA-CRASSA

Three alpha-tubulin isoforms were previously detected in Neurospora cr assa. We have cloned and analysed two alpha-tubulin cDNAs, Tub alpha A and Tub alpha B that encode polypeptides of 453 and 451 amino acids, respectively, The encoded amino acids exhibit an unusual divergence of 35%. This is the highest divergence ever observed between alpha-tubul ins from the same species. The expression of the two genes is developm entally regulated. We did not detect any transcription of the Tub alph a A gene in dormant macroconidia and during the first 30 min of develo pment even though the alpha-tub A protein is already present in the ea rly stage of germination. In contrast, the Tub alpha B gene is continu ously transcribed during the vegetative cycle and the expression profi le of the protein follows the ones of its mRNA.