Worm Breeder's Gazette 11(2): 63
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
Tubulin isotypes in C. elegans are coded by a small family of alpha and beta tubulin genes identified by using heterologous probes from chicken tubulin genes (Don Cleveland). These have been named as alpha- 1 and alpha-2, and -1, -2, -3 and -4.(Linda Gremke, Ph.D. thesis, 1987). We have obtained the alpha-2 gene genomic DNA clone from J. Culotti and L. Gremke, and subcloned it into a pUC119 vector. The 4. 5 kb insert has been cut by SalI, appropriate deletions made, and its nucleotide sequence has been partially determined. The restriction map of the alpha-2 tubulin gene is given below. Amino acid sequence deduced from the nucleotide sequence of this gene shows a 94% amino acid sequence homology with the alpha-1 tubulin gene from C. elegans, cloned by direct screening of a cDNA expression library using anti- tubulin monoclonal antibody 3A5 (Kindly provided by M. Fuller). Other sequence homologies with alpha tubulin amino acid sequences are: Human, 89%; pig brain, 88%; Drosophila A3, 86%; Drosophila A1, 87%; S. pombe A2, 77%, and S. pombe A1, 76%. [See Figure 1] One remarkable observation in the amino acid sequence of the alpha-2 tubulin gene from C. elegans is that a stretch of nine amino acids ( #280-288) i.e. 27 nucleotides are missing from the coding region of the sequence, shown here by the dashes in the sequence. A simple explanation is that an internal deletion may have spontaneously arisen in the sequencing vector, eliminating these 27 bases. We are now reisolating this region of the sequence from another cDNA library and double checking our observation. If the nine amino acids are indeed missing, this will be a novel alpha tubulin in metazoans with a truncated tubulin sequence at this position. [See Figure 2] We thank the support provided by Dr. Johji Miwa of NEC, Tsukuba Lab, in nucleotide sequencing of this gene, and the discussions with Mr. Hachiro Yasuda, Drs. Y. Tabuse, K. Nishiwaki, and T. Sanno.
