Isolation of a cDNA encoding a homologue of actin from Porphyra yezoensis (Rhodophyta)

We report the nucleotide sequence of a cDNA encoding an actin from a marine red alga, Porphyra yezoensis Ueda. A cDNA clone was isolated from a leafy gametophyte cDNA library and analyzed for the sequence. The clone contained an open reading frame for a protein of 373 amino acids which exhibits sequence similarity to known actins. The GC content of the third position (83.9%) was much higher than that at the first (56.3%) and second (42.4%) positions. The actin forms a gene family in the P. yezoensis genome. Comparison of the deduced amino acid sequence showed higher similarity to the Florideophycidae Chondrus crispus (85%) than to the Protoflorideophycidae Cyanidioschyzon merolae (70%). The mRNA was detected in both the leafy gametophytes and filamentous sporophytes. The nucleotide sequence data reported in this paper will appear in the DDBJ/EMBL/ GenBank databases under accession number AB039831.