CLONING AND CHARACTERIZATION OF A GENE ENCODING AN ACTIN-RELATED PROTEIN IN CHLAMYDOMONAS

The genomic sequence of an actin-related gene in Chlamydomonas reinhar dtii has been determined. The deduced amino acid sequence of this gene shares a 63.9% identity with that of a recently reported conventional actin-encoding gene in C. reinhardtii. Phylogenetic analysis shows th at the product of this actin-related gene does not fit into convention al actin or any major actin-related protein categories. The actin-rela ted gene in C. reinhardtii contains seven introns in the coding region and, as described for the conventional actin gene, it contains severa l sequences similar to the 'tub box' sequence motif in its 5'-upstream region. Southern blot analysis of the gene shows a hybridization patt ern different from that of the conventional actin gene, indicating tha t these genes are distinct from one another. Northern blot analysis of poly(A)(+) RNA shows the messages of the two genes to be very similar in size, yet the message level of the actin-related gene is significa ntly lower than that of the conventional actin gene. (C) 1997 Elsevier Science B.V.